diff --git a/bin/jam/args.test.ts b/bin/jam/args.test.ts
index 22bd1e7cb..44e754379 100644
--- a/bin/jam/args.test.ts
+++ b/bin/jam/args.test.ts
@@ -1,6 +1,6 @@
 import assert from "node:assert";
 import { describe, it } from "node:test";
-
+import { PvmBackend, PvmBackendNames } from "@typeberry/config";
 import { NODE_DEFAULTS } from "@typeberry/config-node";
 import { tryAsU16 } from "@typeberry/numbers";
 import { deepEqual } from "@typeberry/utils";
@@ -11,6 +11,7 @@ describe("CLI", () => {
   const defaultOptions: SharedOptions = {
     nodeName: NODE_DEFAULTS.name,
     configPath: NODE_DEFAULTS.config,
+    pvm: NODE_DEFAULTS.pvm,
   };
 
   it("should start with default arguments", () => {
@@ -82,6 +83,30 @@ describe("CLI", () => {
     });
   });
 
+  it("should parse pvm option", () => {
+    const args = parse(["--pvm=ananas"]);
+
+    deepEqual(args, {
+      command: Command.Run,
+      args: {
+        ...defaultOptions,
+        pvm: PvmBackend.Ananas,
+      },
+    });
+  });
+
+  it("should throw on invalid pvm option", () => {
+    const pvms = PvmBackendNames.join(", ");
+    assert.throws(
+      () => {
+        const _args = parse(["--pvm=unimplemented"]);
+      },
+      {
+        message: `Invalid value 'unimplemented' for option 'pvm': Error: Use one of ${pvms}`,
+      },
+    );
+  });
+
   it("should throw on missing output path", () => {
     assert.throws(
       () => {
diff --git a/bin/jam/args.ts b/bin/jam/args.ts
index 2d6423306..1eef39b93 100644
--- a/bin/jam/args.ts
+++ b/bin/jam/args.ts
@@ -1,3 +1,4 @@
+import { type PvmBackend, PvmBackendNames } from "@typeberry/config";
 import { DEFAULT_CONFIG, DEV_CONFIG, NODE_DEFAULTS } from "@typeberry/config-node";
 import { isU16, type U16 } from "@typeberry/numbers";
 import minimist from "minimist";
@@ -18,6 +19,8 @@ Options:
                         [default: ${NODE_DEFAULTS.name}]
   --config              Path to a config file or one of: ['${DEV_CONFIG}', '${DEFAULT_CONFIG}'].
                         [default: ${NODE_DEFAULTS.config}]
+  --pvm                 PVM Backend, one of: [${PvmBackendNames.join(", ")}].
+                        [default: ${PvmBackendNames[NODE_DEFAULTS.pvm]}]
 `;
 
 /** Command to execute. */
@@ -37,6 +40,7 @@ export enum Command {
 export type SharedOptions = {
   nodeName: string;
   configPath: string;
+  pvm: PvmBackend;
 };
 
 export type Arguments =
@@ -79,10 +83,23 @@ function parseSharedOptions(
     (v) => (v === DEV_CONFIG || v === DEFAULT_CONFIG ? v : withRelPath(v)),
     defaultConfig,
   );
+  const { pvm } = parseStringOption(
+    args,
+    "pvm",
+    (v) => {
+      const pvm = PvmBackendNames.indexOf(v);
+      if (pvm >= 0) {
+        return pvm as PvmBackend;
+      }
+      throw Error(`Use one of ${PvmBackendNames.join(", ")}`);
+    },
+    NODE_DEFAULTS.pvm,
+  );
 
   return {
     nodeName: name,
     configPath: config,
+    pvm,
   };
 }
 
diff --git a/bin/jam/build-for-npm.sh b/bin/jam/build-for-npm.sh
index 1fe6f49ad..add9d7b48 100755
--- a/bin/jam/build-for-npm.sh
+++ b/bin/jam/build-for-npm.sh
@@ -16,9 +16,10 @@ DIST_FOLDER=./dist/jam
 mkdir $DIST_FOLDER || true
 rm -rf $DIST_FOLDER/*
 
-
+# TODO [ToDr] Temporary require anan-as before https://github.com/tomusdrw/anan-as/issues/99
+# is resolved.
 # Build the main binary
-BUILD="npx @vercel/ncc build -a -s -e lmdb -e @matrixai/quic -e tsx/esm/api"
+BUILD="npx @vercel/ncc build -a -s -e lmdb -e @matrixai/quic -e @fluffylabs/anan-as -e tsx/esm/api"
 $BUILD ./bin/jam/index.ts -o $DIST_FOLDER
 
 # Fix un-compiled worker files to point to the ones we will compile manually.
@@ -80,7 +81,8 @@ cat > ./package.json << EOF
   },
   "dependencies": {
     "lmdb": "3.1.3",
-    "@matrixai/quic": "2.0.9"
+    "@matrixai/quic": "2.0.9",
+    "@fluffylabs/anan-as": "1.0.0-a9b8141"
   },
   "homepage": "https://typeberry.dev",
   "author": "Fluffy Labs <hello@fluffylabs.dev>",
diff --git a/bin/jam/index.ts b/bin/jam/index.ts
index 309b4e0ca..6f5b2eb9e 100755
--- a/bin/jam/index.ts
+++ b/bin/jam/index.ts
@@ -63,6 +63,7 @@ async function prepareConfigFile(args: Arguments, blake2b: Blake2b): Promise<Jam
     isAuthoring: args.command === Command.Dev,
     nodeName,
     nodeConfig,
+    pvmBackend: args.args.pvm,
     networkConfig: {
       key: devNetworkingSeed(blake2b, nodeName),
       host: "127.0.0.1",
diff --git a/bin/pvm/index.ts b/bin/pvm/index.ts
index 24808d882..3edb5f358 100644
--- a/bin/pvm/index.ts
+++ b/bin/pvm/index.ts
@@ -1,29 +1,48 @@
 // biome-ignore-all lint/suspicious/noConsole: bin file
 
-import { Interpreter, tryAsGas } from "@typeberry/pvm-interpreter";
-import { Status } from "@typeberry/pvm-interpreter/status.js";
-
-const pvm = new Interpreter();
+import { Status, tryAsGas } from "@typeberry/pvm-interface";
+import { Interpreter } from "@typeberry/pvm-interpreter";
+import { AnanasInterpreter } from "@typeberry/pvm-interpreter-ananas";
 
 const program = new Uint8Array([
   0, 0, 35, 173, 101, 126, 173, 255, 239, 101, 101, 101, 101, 101, 194, 101, 101, 101, 174, 120, 44, 0, 0, 0, 0, 178,
   230, 174, 73, 44, 0, 0, 0, 0, 178, 230, 174, 120, 73, 85, 65, 2, 4,
 ]);
-pvm.reset(program, 0, tryAsGas(200n));
-const instructions = pvm.printProgram();
+
+const pvmTb = new Interpreter({ useSbrkGas: true });
+const pvmAnanas = await AnanasInterpreter.new();
+
+pvmTb.resetGeneric(program, 0, tryAsGas(200n));
+pvmAnanas.resetGeneric(program, 0, tryAsGas(200n));
+
+const instructions = pvmTb.printProgram();
 
 let i = 0;
-while (pvm.nextStep() === Status.OK) {
+let ananas = pvmAnanas.nextStep();
+let tb = Status.OK;
+
+while (ananas || tb === Status.OK) {
   console.info(`Instruction ${i}: ${instructions[i]}`);
-  console.info(`Registers: ${pvm.getRegisters().getAllU64()}`);
-  console.info(`Status: ${pvm.getStatus()}`);
-  console.info(`Gas: ${pvm.getGas()}`);
-  console.info(`Gas: ${pvm.getPC()}`);
+  console.info(`🫐 Registers: ${pvmTb.registers.getAllU64()}`);
+  console.info(`🍍 Registers: ${pvmAnanas.registers.getAllU64()}`);
+  console.info(`Status: 🫐 ${pvmTb.getStatus()} | 🍍 ${pvmAnanas.getStatus()}`);
+  console.info(`Gas: 🫐 ${pvmTb.gas.get()}| 🍍 ${pvmAnanas.gas.get()}`);
+  console.info(`PC: 🫐 ${pvmTb.getPC()} | 🍍 ${pvmAnanas.getPC()}`);
   console.info();
   i++;
+  if (tb === Status.OK) {
+    tb = pvmTb.nextStep();
+  }
+  if (ananas) {
+    ananas = pvmAnanas.nextStep();
+  }
 }
+
 console.info(`Instruction ${i}: ${instructions[i]}`);
-console.info(`Registers: ${pvm.getRegisters().getAllU64()}`);
-console.info(`Status: ${pvm.getStatus()}`);
-console.info(`Gas: ${pvm.getGas()}`);
-console.info(`Gas: ${pvm.getPC()}`);
+console.info(`🫐 Registers: ${pvmTb.registers.getAllU64()}`);
+console.info(`🍍 Registers: ${pvmAnanas.registers.getAllU64()}`);
+console.info(`Status: 🫐 ${pvmTb.getStatus()} | 🍍 ${pvmAnanas.getStatus()}`);
+// TODO [MaSo] Check why they not finished with same gas.
+console.info(`Gas: 🫐 ${pvmTb.gas.get()}| 🍍 ${pvmAnanas.gas.get()}`);
+console.info(`PC: 🫐 ${pvmTb.getPC()} | 🍍 ${pvmAnanas.getPC()}`);
+console.info();
diff --git a/bin/pvm/package.json b/bin/pvm/package.json
index 48bdf2e0a..5eb200d6a 100644
--- a/bin/pvm/package.json
+++ b/bin/pvm/package.json
@@ -4,7 +4,9 @@
   "description": "PVM program runner.",
   "main": "index.ts",
   "dependencies": {
-    "@typeberry/pvm-interpreter": "*"
+    "@typeberry/pvm-interface": "*",
+    "@typeberry/pvm-interpreter": "*",
+    "@typeberry/pvm-interpreter-ananas": "*"
   },
   "scripts": {
     "start": "tsx ./index.ts",
diff --git a/bin/rpc/test/e2e-setup.ts b/bin/rpc/test/e2e-setup.ts
index ecfe93ac3..924b32f58 100644
--- a/bin/rpc/test/e2e-setup.ts
+++ b/bin/rpc/test/e2e-setup.ts
@@ -11,7 +11,7 @@ const withRelPath = workspacePathFix(`${import.meta.dirname}/../../..`);
 
 async function main() {
   const nodeConfig = loadConfig(`${import.meta.dirname}/e2e.config.json`);
-  const jamConfig = JamConfig.new({ nodeName: NODE_DEFAULTS.name, nodeConfig });
+  const jamConfig = JamConfig.new({ nodeName: NODE_DEFAULTS.name, nodeConfig, pvmBackend: NODE_DEFAULTS.pvm });
   try {
     const api = await node(jamConfig, withRelPath);
     await importBlocks(api, blocksToImport);
diff --git a/bin/tci/index.test.ts b/bin/tci/index.test.ts
index bc7772e6d..00760f43b 100644
--- a/bin/tci/index.test.ts
+++ b/bin/tci/index.test.ts
@@ -13,6 +13,7 @@ describe("Typeberry Common Interface: Config", () => {
     nodeName: NODE_DEFAULTS.name,
     nodeConfig: loadConfig(NODE_DEFAULTS.config),
     devConfig: DEFAULT_DEV_CONFIG,
+    pvmBackend: NODE_DEFAULTS.pvm,
   });
   const key = Bytes.fill(SEED_SIZE, 1).asOpaque<PublicKeySeed>();
 
diff --git a/bin/tci/index.ts b/bin/tci/index.ts
index a7170eb9a..5d939124e 100755
--- a/bin/tci/index.ts
+++ b/bin/tci/index.ts
@@ -80,7 +80,12 @@ export function createJamConfig(argv: CommonArguments): node.JamConfig {
     };
   }
 
-  return node.JamConfig.new({ nodeName: NODE_DEFAULTS.name, nodeConfig, devConfig });
+  return node.JamConfig.new({
+    nodeName: NODE_DEFAULTS.name,
+    nodeConfig,
+    devConfig,
+    pvmBackend: NODE_DEFAULTS.pvm,
+  });
 }
 
 if (import.meta.url === pathToFileURL(process.argv[1]).href) {
diff --git a/bin/test-runner/package.json b/bin/test-runner/package.json
index 407cbe911..53522b6da 100644
--- a/bin/test-runner/package.json
+++ b/bin/test-runner/package.json
@@ -10,6 +10,7 @@
     "@typeberry/codec": "*",
     "@typeberry/collections": "*",
     "@typeberry/config": "*",
+    "@typeberry/config-node": "*",
     "@typeberry/crypto": "*",
     "@typeberry/database": "*",
     "@typeberry/disputes": "*",
@@ -18,6 +19,7 @@
     "@typeberry/json-parser": "*",
     "@typeberry/logger": "*",
     "@typeberry/numbers": "*",
+    "@typeberry/pvm-interface": "*",
     "@typeberry/pvm-interpreter": "*",
     "@typeberry/safrole": "*",
     "@typeberry/shuffling": "*",
diff --git a/bin/test-runner/w3f/accumulate.ts b/bin/test-runner/w3f/accumulate.ts
index f216732c3..9297f8638 100644
--- a/bin/test-runner/w3f/accumulate.ts
+++ b/bin/test-runner/w3f/accumulate.ts
@@ -12,7 +12,7 @@ import type { WorkPackageHash } from "@typeberry/block/refine-context.js";
 import type { WorkReport } from "@typeberry/block/work-report.js";
 import { fromJson, workReportFromJson } from "@typeberry/block-json";
 import { asKnownSize, HashSet } from "@typeberry/collections";
-import type { ChainSpec } from "@typeberry/config";
+import { type ChainSpec, PvmBackend, PvmBackendNames } from "@typeberry/config";
 import { Blake2b } from "@typeberry/hash";
 import { type FromJson, json } from "@typeberry/json-parser";
 import type { InMemoryService } from "@typeberry/state";
@@ -142,8 +142,15 @@ export class AccumulateTest {
 }
 
 export async function runAccumulateTest(test: AccumulateTest, path: string) {
-  const chainSpec = getChainSpec(path);
+  await runAccumulateInternal(test, path, PvmBackend.BuiltIn);
+}
 
+export async function runAccumulateTestAnanas(test: AccumulateTest, path: string) {
+  await runAccumulateInternal(test, path, PvmBackend.Ananas);
+}
+
+async function runAccumulateInternal(test: AccumulateTest, path: string, pvm: PvmBackend) {
+  const chainSpec = getChainSpec(path);
   /**
    * entropy has to be moved to input because state is incompatibile -
    * in test state we have: `entropy: EntropyHash;`
@@ -152,19 +159,19 @@ export async function runAccumulateTest(test: AccumulateTest, path: string) {
    */
   const entropy = test.pre_state.entropy;
 
-  const state = TestState.toAccumulateState(test.pre_state as TestState, chainSpec);
-  const accumulate = new Accumulate(chainSpec, await Blake2b.createHasher(), state);
+  const post_state = TestState.toAccumulateState(test.post_state, chainSpec);
+
+  const state = TestState.toAccumulateState(test.pre_state, chainSpec);
+  const accumulate = new Accumulate(chainSpec, await Blake2b.createHasher(), state, pvm);
   const accumulateOutput = new AccumulateOutput();
   const result = await accumulate.transition({ ...test.input, entropy });
-
   if (result.isError) {
-    assert.fail(`Expected successfull accumulation, got: ${result}`);
+    assert.fail(`Expected successfull accumulation for ${PvmBackendNames[pvm]}, got: ${result}`);
   }
-  const accumulateRoot = await accumulateOutput.transition({ accumulationOutputLog: result.ok.accumulationOutputLog });
+  const accumulateRoot = await accumulateOutput.transition({
+    accumulationOutputLog: result.ok.accumulationOutputLog,
+  });
   state.applyUpdate(result.ok.stateUpdate);
-
-  const post_state = TestState.toAccumulateState(test.post_state as TestState, chainSpec);
-
   deepEqual(state, post_state);
   deepEqual(accumulateRoot, test.output.ok);
 }
diff --git a/bin/test-runner/w3f/pvm-gas-cost.ts b/bin/test-runner/w3f/pvm-gas-cost.ts
index 2ab18784e..e2afcf9b5 100644
--- a/bin/test-runner/w3f/pvm-gas-cost.ts
+++ b/bin/test-runner/w3f/pvm-gas-cost.ts
@@ -1,7 +1,8 @@
 import assert from "node:assert";
 import { fromJson } from "@typeberry/block-json";
 import { type FromJson, json } from "@typeberry/json-parser";
-import { Interpreter, tryAsGas } from "@typeberry/pvm-interpreter";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { Interpreter } from "@typeberry/pvm-interpreter";
 
 export class PvmGasCostTest {
   static fromJson: FromJson<PvmGasCostTest> = {
@@ -15,7 +16,7 @@ export class PvmGasCostTest {
 
 export async function runPvmGasCostTest(testContent: PvmGasCostTest) {
   const pvm = new Interpreter();
-  pvm.reset(testContent.program, 0, tryAsGas(1000));
+  pvm.resetGeneric(testContent.program, 0, tryAsGas(1000));
 
   const blockGasCosts = pvm.calculateBlockGasCost();
 
diff --git a/bin/test-runner/w3f/pvm.ts b/bin/test-runner/w3f/pvm.ts
index 235c94b51..cd51d7983 100644
--- a/bin/test-runner/w3f/pvm.ts
+++ b/bin/test-runner/w3f/pvm.ts
@@ -1,14 +1,14 @@
 import assert from "node:assert";
 import { fromJson } from "@typeberry/block-json";
 import { type FromJson, json } from "@typeberry/json-parser";
-import { Interpreter, tryAsGas } from "@typeberry/pvm-interpreter";
+import { MAX_MEMORY_INDEX, Status, tryAsGas } from "@typeberry/pvm-interface";
+import { Interpreter } from "@typeberry/pvm-interpreter";
 import { MemoryBuilder } from "@typeberry/pvm-interpreter/memory/index.js";
-import { MAX_MEMORY_INDEX, PAGE_SIZE } from "@typeberry/pvm-interpreter/memory/memory-consts.js";
+import { PAGE_SIZE } from "@typeberry/pvm-interpreter/memory/memory-consts.js";
 import { tryAsMemoryIndex, tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
 import { getPageNumber } from "@typeberry/pvm-interpreter/memory/memory-utils.js";
 import { type PageNumber, tryAsPageNumber } from "@typeberry/pvm-interpreter/memory/pages/page-utils.js";
 import { Registers } from "@typeberry/pvm-interpreter/registers.js";
-import { Status } from "@typeberry/pvm-interpreter/status.js";
 import { safeAllocUint8Array } from "@typeberry/utils";
 
 class MemoryChunkItem {
@@ -113,12 +113,12 @@ export async function runPvmTest(testContent: PvmTest) {
     return "halt";
   };
 
-  pvm.reset(testContent.program, testContent["initial-pc"], tryAsGas(testContent["initial-gas"]), regs, memory);
+  pvm.resetGeneric(testContent.program, testContent["initial-pc"], tryAsGas(testContent["initial-gas"]), regs, memory);
   pvm.runProgram();
 
-  assert.strictEqual(pvm.getGas(), BigInt(testContent["expected-gas"]));
+  assert.strictEqual(pvm.gas.get(), BigInt(testContent["expected-gas"]));
   assert.strictEqual(pvm.getPC(), testContent["expected-pc"]);
-  assert.deepStrictEqual(pvm.getRegisters().getAllU64(), testContent["expected-regs"]);
+  assert.deepStrictEqual(pvm.registers.getAllU64(), testContent["expected-regs"]);
 
   const testStatus = mapPvmStatus(pvm.getStatus());
   const exitParam = pvm.getExitParam();
diff --git a/bin/test-runner/w3f/runners.ts b/bin/test-runner/w3f/runners.ts
index befd1046e..b214e3c51 100644
--- a/bin/test-runner/w3f/runners.ts
+++ b/bin/test-runner/w3f/runners.ts
@@ -14,7 +14,7 @@ import {
 import { fullChainSpec, tinyChainSpec } from "@typeberry/config";
 import { runner } from "../common.js";
 import { runStateTransition, StateTransition } from "../state-transition/state-transition.js";
-import { AccumulateTest, runAccumulateTest } from "./accumulate.js";
+import { AccumulateTest, runAccumulateTest, runAccumulateTestAnanas } from "./accumulate.js";
 import { AssurancesTestFull, AssurancesTestTiny, runAssurancesTestFull, runAssurancesTestTiny } from "./assurances.js";
 import { AuthorizationsTest, runAuthorizationsTest } from "./authorizations.js";
 import {
@@ -50,6 +50,7 @@ import { runTrieTest, trieTestSuiteFromJson } from "./trie.js";
 
 export const runners = [
   runner("accumulate", AccumulateTest.fromJson, runAccumulateTest),
+  runner("accumulate_ananas", AccumulateTest.fromJson, runAccumulateTestAnanas),
   runner("assurances/tiny", AssurancesTestTiny.fromJson, runAssurancesTestTiny),
   runner("assurances/full", AssurancesTestFull.fromJson, runAssurancesTestFull),
   runner("authorizations", AuthorizationsTest.fromJson, runAuthorizationsTest),
diff --git a/package-lock.json b/package-lock.json
index f30062c20..4848fd75d 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -35,7 +35,9 @@
         "packages/core/ordering",
         "packages/core/pvm-debugger-adapter",
         "packages/core/pvm-host-calls",
+        "packages/core/pvm-interface",
         "packages/core/pvm-interpreter",
+        "packages/core/pvm-interpreter-ananas",
         "packages/core/pvm-program",
         "packages/core/pvm-spi-decoder",
         "packages/core/shuffling",
@@ -236,7 +238,9 @@
       "version": "0.2.0",
       "license": "MPL-2.0",
       "dependencies": {
-        "@typeberry/pvm-interpreter": "*"
+        "@typeberry/pvm-interface": "*",
+        "@typeberry/pvm-interpreter": "*",
+        "@typeberry/pvm-interpreter-ananas": "*"
       }
     },
     "bin/rpc": {
@@ -299,6 +303,7 @@
         "@typeberry/codec": "*",
         "@typeberry/collections": "*",
         "@typeberry/config": "*",
+        "@typeberry/config-node": "*",
         "@typeberry/crypto": "*",
         "@typeberry/database": "*",
         "@typeberry/disputes": "*",
@@ -307,6 +312,7 @@
         "@typeberry/json-parser": "*",
         "@typeberry/logger": "*",
         "@typeberry/numbers": "*",
+        "@typeberry/pvm-interface": "*",
         "@typeberry/pvm-interpreter": "*",
         "@typeberry/safrole": "*",
         "@typeberry/shuffling": "*",
@@ -2425,10 +2431,18 @@
       "resolved": "packages/core/pvm-host-calls",
       "link": true
     },
+    "node_modules/@typeberry/pvm-interface": {
+      "resolved": "packages/core/pvm-interface",
+      "link": true
+    },
     "node_modules/@typeberry/pvm-interpreter": {
       "resolved": "packages/core/pvm-interpreter",
       "link": true
     },
+    "node_modules/@typeberry/pvm-interpreter-ananas": {
+      "resolved": "packages/core/pvm-interpreter-ananas",
+      "link": true
+    },
     "node_modules/@typeberry/pvm-program": {
       "resolved": "packages/core/pvm-program",
       "link": true
@@ -2536,6 +2550,12 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/@types/long": {
+      "version": "3.0.32",
+      "resolved": "https://registry.npmjs.org/@types/long/-/long-3.0.32.tgz",
+      "integrity": "sha512-ZXyOOm83p7X8p3s0IYM3VeueNmHpkk/yMlP8CLeOnEcu6hIwPH7YjZBvhQkR0ZFS2DqZAxKtJ/M5fcuv3OU5BA==",
+      "license": "MIT"
+    },
     "node_modules/@types/minimist": {
       "version": "1.2.5",
       "resolved": "https://registry.npmjs.org/@types/minimist/-/minimist-1.2.5.tgz",
@@ -2558,6 +2578,12 @@
       "integrity": "sha512-60BCwRFOZCQhDncwQdxxeOEEkbc5dIMccYLwbxsS4TUNeVECQ/pBJ0j09mrHOl/JJvpRPGwO9SvE4nR2Nb/a4Q==",
       "license": "MIT"
     },
+    "node_modules/@types/webassembly-js-api": {
+      "version": "0.0.1",
+      "resolved": "https://registry.npmjs.org/@types/webassembly-js-api/-/webassembly-js-api-0.0.1.tgz",
+      "integrity": "sha512-QPUg0o1GcGl035Z+lhje3uMapJh4/MqYQPLo/5wB4XwJbRQXkYMPVlDWZwFxy3CatnBIzaK7eFHpRn7tS83xzg==",
+      "license": "MIT"
+    },
     "node_modules/@types/ws": {
       "version": "8.18.1",
       "resolved": "https://registry.npmjs.org/@types/ws/-/ws-8.18.1.tgz",
@@ -3016,6 +3042,17 @@
         "node": ">=12.0.0"
       }
     },
+    "node_modules/assemblyscript-loader": {
+      "version": "0.3.0",
+      "resolved": "https://registry.npmjs.org/assemblyscript-loader/-/assemblyscript-loader-0.3.0.tgz",
+      "integrity": "sha512-Z4320V+ImJqtCHO9M1ZsZY931YQ+Dq3/KmwgB49DEHrdr8AD+pF+9VSiQio5Wa8YmMOPP8kLjZ1rqTTvSlylYQ==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "@types/long": "^3.0.32",
+        "@types/webassembly-js-api": "0.0.1",
+        "long": "^3.2.0"
+      }
+    },
     "node_modules/astral-regex": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/astral-regex/-/astral-regex-2.0.0.tgz",
@@ -5004,6 +5041,15 @@
         "node": ">=8"
       }
     },
+    "node_modules/long": {
+      "version": "3.2.0",
+      "resolved": "https://registry.npmjs.org/long/-/long-3.2.0.tgz",
+      "integrity": "sha512-ZYvPPOMqUwPoDsbJaR10iQJYnMuZhRTvHYl62ErLIEX7RgFlziSBUUvrt3OVfc47QlHHpzPZYP17g3Fv7oeJkg==",
+      "license": "Apache-2.0",
+      "engines": {
+        "node": ">=0.6"
+      }
+    },
     "node_modules/magic-string": {
       "version": "0.30.17",
       "resolved": "https://registry.npmjs.org/magic-string/-/magic-string-0.30.17.tgz",
@@ -6552,6 +6598,7 @@
         "@typeberry/jam-host-calls": "*",
         "@typeberry/numbers": "*",
         "@typeberry/pvm-host-calls": "*",
+        "@typeberry/pvm-interface": "*",
         "@typeberry/pvm-interpreter": "*",
         "@typeberry/pvm-program": "*",
         "@typeberry/pvm-spi-decoder": "*",
@@ -6563,14 +6610,26 @@
       "version": "0.2.0",
       "license": "MPL-2.0",
       "dependencies": {
+        "@typeberry/config": "^0.2.0",
         "@typeberry/logger": "*",
         "@typeberry/numbers": "*",
+        "@typeberry/pvm-interface": "*",
         "@typeberry/pvm-interpreter": "*",
+        "@typeberry/pvm-interpreter-ananas": "*",
         "@typeberry/pvm-program": "*",
         "@typeberry/pvm-spi-decoder": "*",
         "@typeberry/utils": "*"
       }
     },
+    "packages/core/pvm-interface": {
+      "name": "@typeberry/pvm-interface",
+      "version": "0.1.3",
+      "license": "MPL-2.0",
+      "dependencies": {
+        "@typeberry/numbers": "*",
+        "@typeberry/utils": "*"
+      }
+    },
     "packages/core/pvm-interpreter": {
       "name": "@typeberry/pvm-interpreter",
       "version": "0.2.0",
@@ -6580,9 +6639,34 @@
         "@typeberry/codec": "*",
         "@typeberry/logger": "*",
         "@typeberry/numbers": "*",
+        "@typeberry/pvm-interface": "*",
+        "@typeberry/pvm-program": "*",
         "@typeberry/utils": "*"
       }
     },
+    "packages/core/pvm-interpreter-ananas": {
+      "name": "@typeberry/pvm-interpreter-ananas",
+      "version": "0.1.3",
+      "license": "MPL-2.0",
+      "dependencies": {
+        "@fluffylabs/anan-as": "^1.0.0-a9b8141",
+        "@typeberry/codec": "*",
+        "@typeberry/numbers": "*",
+        "@typeberry/pvm-interface": "*",
+        "@typeberry/utils": "*",
+        "assemblyscript-loader": "^0.3.0"
+      }
+    },
+    "packages/core/pvm-interpreter-ananas/node_modules/@fluffylabs/anan-as": {
+      "version": "1.0.0-a9b8141",
+      "resolved": "https://registry.npmjs.org/@fluffylabs/anan-as/-/anan-as-1.0.0-a9b8141.tgz",
+      "integrity": "sha512-B6hC5I1jCWpen2Cze2GEMs9sZiNZ+0EgowIHKenj2Cjvq75FyUGpVJYktAeEYlLa/GgCaFAC0fP0bVWY/NZ26g==",
+      "license": "MPL-2.0",
+      "dependencies": {
+        "@typeberry/lib": "^0.2.0",
+        "json-bigint-patch": "^0.0.8"
+      }
+    },
     "packages/core/pvm-program": {
       "name": "@typeberry/pvm-program",
       "version": "0.2.0",
@@ -6918,6 +7002,7 @@
         "@typeberry/logger": "*",
         "@typeberry/numbers": "*",
         "@typeberry/pvm-host-calls": "*",
+        "@typeberry/pvm-interface": "*",
         "@typeberry/pvm-interpreter": "*",
         "@typeberry/state": "*",
         "@typeberry/utils": "*"
@@ -7108,6 +7193,7 @@
         "@typeberry/mmr": "*",
         "@typeberry/numbers": "*",
         "@typeberry/pvm-host-calls": "*",
+        "@typeberry/pvm-interface": "*",
         "@typeberry/pvm-interpreter": "*",
         "@typeberry/pvm-program": "*",
         "@typeberry/safrole": "*",
@@ -7471,6 +7557,7 @@
         "@typeberry/codec": "*",
         "@typeberry/collections": "*",
         "@typeberry/config": "*",
+        "@typeberry/config-node": "*",
         "@typeberry/crypto": "*",
         "@typeberry/database": "*",
         "@typeberry/hash": "*",
diff --git a/package.json b/package.json
index 274fa346e..a9797ff90 100644
--- a/package.json
+++ b/package.json
@@ -30,7 +30,9 @@
     "packages/core/ordering",
     "packages/core/pvm-debugger-adapter",
     "packages/core/pvm-host-calls",
+    "packages/core/pvm-interface",
     "packages/core/pvm-interpreter",
+    "packages/core/pvm-interpreter-ananas",
     "packages/core/pvm-program",
     "packages/core/pvm-spi-decoder",
     "packages/core/shuffling",
diff --git a/packages/README.md b/packages/README.md
index 937de2ac6..c5232b2de 100644
--- a/packages/README.md
+++ b/packages/README.md
@@ -23,7 +23,9 @@ Contains fundamental packages that provide low-level functionality and utilities
 - **ordering** - Ordering and sorting utilities
 - **pvm-debugger-adapter** - PVM debugger adapter
 - **pvm-host-calls** - PVM host call implementations
+- **pvm-interface** - PVM interface definitions
 - **pvm-interpreter** - PVM interpreter functionality
+- **pvm-interpreter-ananas** - Ananas PVM interpreter implementation
 - **pvm-program** - PVM program utilities
 - **pvm-spi-decoder** - PVM SPI decoder
 - **shuffling** - Shuffling algorithms
@@ -41,6 +43,7 @@ Contains JAM (Join-Accumulate Machine) specific packages:
 - **database-lmdb** - LMDB database implementation
 - **fuzz-proto** - Fuzzing protocol implementation
 - **jam-host-calls** - JAM-specific host calls
+- **jamnp-protocol** - JAM network protocol definitions
 - **jamnp-s** - JAM network protocol implementation
 - **node** - JAM node implementation
 - **safrole** - Safrole consensus mechanism
diff --git a/packages/core/pvm-debugger-adapter/debugger-adapter.ts b/packages/core/pvm-debugger-adapter/debugger-adapter.ts
index 601238207..22f6c6eb1 100644
--- a/packages/core/pvm-debugger-adapter/debugger-adapter.ts
+++ b/packages/core/pvm-debugger-adapter/debugger-adapter.ts
@@ -1,8 +1,7 @@
+import { Status, tryAsGas } from "@typeberry/pvm-interface";
 import { Interpreter, type Memory, tryAsMemoryIndex } from "@typeberry/pvm-interpreter";
-import { tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
 import { PAGE_SIZE } from "@typeberry/pvm-interpreter/memory/memory-consts.js";
 import { Registers } from "@typeberry/pvm-interpreter/registers.js";
-import { Status } from "@typeberry/pvm-interpreter/status.js";
 import { check, safeAllocUint8Array } from "@typeberry/utils";
 
 export class DebuggerAdapter {
@@ -18,11 +17,11 @@ export class DebuggerAdapter {
   }
 
   resetGeneric(rawProgram: Uint8Array, flatRegisters: Uint8Array, initialGas: bigint) {
-    this.pvm.reset(rawProgram, 0, tryAsGas(initialGas), new Registers(flatRegisters));
+    this.pvm.resetGeneric(rawProgram, 0, tryAsGas(initialGas), new Registers(flatRegisters));
   }
 
   reset(rawProgram: Uint8Array, pc: number, gas: bigint, maybeRegisters?: Registers, maybeMemory?: Memory) {
-    this.pvm.reset(rawProgram, pc, tryAsGas(gas), maybeRegisters, maybeMemory);
+    this.pvm.resetGeneric(rawProgram, pc, tryAsGas(gas), maybeRegisters, maybeMemory);
   }
 
   getPageDump(pageNumber: number): null | Uint8Array {
@@ -45,7 +44,7 @@ export class DebuggerAdapter {
   }
 
   setMemory(address: number, value: Uint8Array) {
-    this.pvm.getMemory().storeFrom(tryAsMemoryIndex(address), value);
+    this.pvm.memory.storeFrom(tryAsMemoryIndex(address), value);
   }
 
   getExitArg(): number {
@@ -72,11 +71,11 @@ export class DebuggerAdapter {
   }
 
   getRegisters(): BigUint64Array {
-    return this.pvm.getRegisters().getAllU64();
+    return this.pvm.registers.getAllU64();
   }
 
   setRegisters(registers: Uint8Array) {
-    this.pvm.getRegisters().copyFrom(new Registers(registers));
+    this.pvm.registers.copyFrom(new Registers(registers));
   }
 
   getProgramCounter(): number {
@@ -88,10 +87,10 @@ export class DebuggerAdapter {
   }
 
   getGasLeft(): bigint {
-    return BigInt(this.pvm.getGas());
+    return BigInt(this.pvm.gas.get());
   }
 
   setGasLeft(gas: bigint) {
-    this.pvm.getGasCounter().set(tryAsGas(gas));
+    this.pvm.gas.set(tryAsGas(gas));
   }
 }
diff --git a/packages/core/pvm-debugger-adapter/index.ts b/packages/core/pvm-debugger-adapter/index.ts
index 7c2bffcbb..bc4f317b9 100644
--- a/packages/core/pvm-debugger-adapter/index.ts
+++ b/packages/core/pvm-debugger-adapter/index.ts
@@ -3,7 +3,8 @@ export * as bytes from "@typeberry/bytes";
 export * as hash from "@typeberry/hash";
 export * from "@typeberry/jam-host-calls";
 export * as numbers from "@typeberry/numbers";
-export { HostCallMemory, HostCallRegisters, IHostCallMemory, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+export { HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
+export { NO_OF_REGISTERS } from "@typeberry/pvm-interface/registers.js";
 export * as interpreter from "@typeberry/pvm-interpreter";
 export { Args, ArgsDecoder } from "@typeberry/pvm-interpreter/args-decoder/args-decoder.js";
 export { createResults } from "@typeberry/pvm-interpreter/args-decoder/args-decoding-results.js";
@@ -15,7 +16,7 @@ export { instructionArgumentTypeMap } from "@typeberry/pvm-interpreter/args-deco
 export { BasicBlocks } from "@typeberry/pvm-interpreter/basic-blocks/index.js";
 export { Mask } from "@typeberry/pvm-interpreter/program-decoder/mask.js";
 export { ProgramDecoder } from "@typeberry/pvm-interpreter/program-decoder/program-decoder.js";
-export { NO_OF_REGISTERS, Registers } from "@typeberry/pvm-interpreter/registers.js";
+export { Registers } from "@typeberry/pvm-interpreter/registers.js";
 export { extractCodeAndMetadata, Program } from "@typeberry/pvm-program";
 export { decodeStandardProgram, MemorySegment, SpiMemory, SpiProgram } from "@typeberry/pvm-spi-decoder";
 export * from "@typeberry/utils/debug.js";
diff --git a/packages/core/pvm-debugger-adapter/package.json b/packages/core/pvm-debugger-adapter/package.json
index 32b96f03e..f243af5f8 100644
--- a/packages/core/pvm-debugger-adapter/package.json
+++ b/packages/core/pvm-debugger-adapter/package.json
@@ -10,6 +10,7 @@
     "@typeberry/jam-host-calls": "*",
     "@typeberry/numbers": "*",
     "@typeberry/pvm-host-calls": "*",
+    "@typeberry/pvm-interface": "*",
     "@typeberry/pvm-interpreter": "*",
     "@typeberry/pvm-program": "*",
     "@typeberry/pvm-spi-decoder": "*",
diff --git a/packages/core/pvm-host-calls/bin.ts b/packages/core/pvm-host-calls/bin.ts
index 3debefec2..c8d834ace 100644
--- a/packages/core/pvm-host-calls/bin.ts
+++ b/packages/core/pvm-host-calls/bin.ts
@@ -1,31 +1,30 @@
-import { tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
-import { Program } from "@typeberry/pvm-program";
+import { PvmBackend } from "@typeberry/config";
+import { tryAsGas } from "@typeberry/pvm-interface";
 import { HostCalls } from "./host-calls.js";
 import { HostCallsManager, NoopMissing } from "./host-calls-manager.js";
 import { InterpreterInstanceManager } from "./interpreter-instance-manager.js";
 
 const hostCalls = new HostCallsManager({ missing: new NoopMissing(), handlers: [] });
-const pvmInstanceManager = new InterpreterInstanceManager(1);
+const pvmInstanceManager = await InterpreterInstanceManager.new(PvmBackend.BuiltIn);
 const pvmHostCallExtension = new HostCalls(pvmInstanceManager, hostCalls);
 
 const program = new Uint8Array([
-  0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x10, 0x1, 0x0, 0x0, 0xf9, 0x0, 0x0, 0x0, 0x0, 0x0, 0x80, 0xd9, 0x5, 0x12, 0x0,
-  0x0, 0x0, 0x5, 0x11, 0x0, 0x0, 0x0, 0x5, 0xa3, 0x0, 0x0, 0x0, 0x5, 0xc6, 0x0, 0x4, 0x7, 0x13, 0x0, 0x2, 0x11, 0xa4,
-  0x3, 0x10, 0x58, 0x3, 0x15, 0x54, 0x3, 0x16, 0x50, 0xd, 0x11, 0x1c, 0xd, 0x11, 0x18, 0xd, 0x11, 0x14, 0xd, 0x11, 0x10,
-  0xd, 0x11, 0xc, 0xd, 0x11, 0x8, 0xd, 0x11, 0x4, 0xd, 0x1, 0xd, 0x11, 0x3c, 0xd, 0x11, 0x38, 0xd, 0x11, 0x34, 0xd,
-  0x11, 0x30, 0xd, 0x11, 0x2c, 0xd, 0x11, 0x28, 0xd, 0x11, 0x24, 0xd, 0x11, 0x20, 0xd, 0x11, 0x40, 0x52, 0x18, 0x4, 0x9,
-  0x20, 0x2, 0x1a, 0x40, 0x4, 0xb, 0x4, 0x4, 0x7, 0x4e, 0x2, 0x1, 0x15, 0x40, 0xd, 0x11, 0x44, 0x2, 0x18, 0x20, 0x4,
-  0x9, 0x20, 0x2, 0x1a, 0x44, 0x4, 0xb, 0x4, 0x4, 0x7, 0x4e, 0x2, 0x1, 0x16, 0x44, 0x3, 0x15, 0x48, 0x52, 0x17, 0x4,
-  0x8, 0x20, 0x2, 0x19, 0x48, 0x4, 0xa, 0x4, 0x4e, 0x3, 0x3, 0x16, 0x4c, 0x2, 0x17, 0x20, 0x4, 0x8, 0x20, 0x2, 0x19,
-  0x4c, 0x4, 0xa, 0x4, 0x4e, 0x3, 0x4, 0x7, 0x1, 0x10, 0x58, 0x1, 0x15, 0x54, 0x1, 0x16, 0x50, 0x2, 0x11, 0x5c, 0x13,
-  0x0, 0x2, 0x11, 0xec, 0x3, 0x10, 0x10, 0xd, 0x11, 0x8, 0xd, 0x11, 0x4, 0xd, 0x1, 0x1a, 0x11, 0xf, 0x2, 0x17, 0xf, 0x4,
-  0x8, 0x1, 0x52, 0x19, 0x4, 0xa, 0xc, 0x4e, 0x3, 0x4, 0x7, 0x1, 0x10, 0x10, 0x2, 0x11, 0x14, 0x13, 0x0, 0x4, 0x7, 0x13,
-  0x0, 0x21, 0x84, 0x54, 0x92, 0x24, 0x49, 0x92, 0x92, 0x24, 0x49, 0x52, 0x92, 0x4a, 0x92, 0xa4, 0x92, 0x92, 0x94, 0x24,
-  0xa9, 0x24, 0x29, 0x49, 0x4a, 0x52, 0x2a, 0xa9, 0x0,
+  0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x10, 0x1, 0x0, 0x0, 0xf9, 0x0, 0x0, 0x0, 0x0, 0x0, 0x80, 0xd9, 0x5, 0x12,
+  0x0, 0x0, 0x0, 0x5, 0x11, 0x0, 0x0, 0x0, 0x5, 0xa3, 0x0, 0x0, 0x0, 0x5, 0xc6, 0x0, 0x4, 0x7, 0x13, 0x0, 0x2, 0x11,
+  0xa4, 0x3, 0x10, 0x58, 0x3, 0x15, 0x54, 0x3, 0x16, 0x50, 0xd, 0x11, 0x1c, 0xd, 0x11, 0x18, 0xd, 0x11, 0x14, 0xd, 0x11,
+  0x10, 0xd, 0x11, 0xc, 0xd, 0x11, 0x8, 0xd, 0x11, 0x4, 0xd, 0x1, 0xd, 0x11, 0x3c, 0xd, 0x11, 0x38, 0xd, 0x11, 0x34,
+  0xd, 0x11, 0x30, 0xd, 0x11, 0x2c, 0xd, 0x11, 0x28, 0xd, 0x11, 0x24, 0xd, 0x11, 0x20, 0xd, 0x11, 0x40, 0x52, 0x18, 0x4,
+  0x9, 0x20, 0x2, 0x1a, 0x40, 0x4, 0xb, 0x4, 0x4, 0x7, 0x4e, 0x2, 0x1, 0x15, 0x40, 0xd, 0x11, 0x44, 0x2, 0x18, 0x20,
+  0x4, 0x9, 0x20, 0x2, 0x1a, 0x44, 0x4, 0xb, 0x4, 0x4, 0x7, 0x4e, 0x2, 0x1, 0x16, 0x44, 0x3, 0x15, 0x48, 0x52, 0x17,
+  0x4, 0x8, 0x20, 0x2, 0x19, 0x48, 0x4, 0xa, 0x4, 0x4e, 0x3, 0x3, 0x16, 0x4c, 0x2, 0x17, 0x20, 0x4, 0x8, 0x20, 0x2,
+  0x19, 0x4c, 0x4, 0xa, 0x4, 0x4e, 0x3, 0x4, 0x7, 0x1, 0x10, 0x58, 0x1, 0x15, 0x54, 0x1, 0x16, 0x50, 0x2, 0x11, 0x5c,
+  0x13, 0x0, 0x2, 0x11, 0xec, 0x3, 0x10, 0x10, 0xd, 0x11, 0x8, 0xd, 0x11, 0x4, 0xd, 0x1, 0x1a, 0x11, 0xf, 0x2, 0x17,
+  0xf, 0x4, 0x8, 0x1, 0x52, 0x19, 0x4, 0xa, 0xc, 0x4e, 0x3, 0x4, 0x7, 0x1, 0x10, 0x10, 0x2, 0x11, 0x14, 0x13, 0x0, 0x4,
+  0x7, 0x13, 0x0, 0x21, 0x84, 0x54, 0x92, 0x24, 0x49, 0x92, 0x92, 0x24, 0x49, 0x52, 0x92, 0x4a, 0x92, 0xa4, 0x92, 0x92,
+  0x94, 0x24, 0xa9, 0x24, 0x29, 0x49, 0x4a, 0x52, 0x2a, 0xa9, 0x0,
 ]);
 const args = new Uint8Array();
-const { code, memory, registers } = Program.fromSpi(program, args, false);
 
 (async () => {
-  await pvmHostCallExtension.runProgram(code, 5, tryAsGas(1000), registers, memory);
+  await pvmHostCallExtension.runProgram(program, args, 5, tryAsGas(1000));
 })();
diff --git a/packages/core/pvm-host-calls/host-call-handler.ts b/packages/core/pvm-host-calls/host-call-handler.ts
index 0bf1d91ef..ba0202d6b 100644
--- a/packages/core/pvm-host-calls/host-call-handler.ts
+++ b/packages/core/pvm-host-calls/host-call-handler.ts
@@ -1,9 +1,9 @@
 import { tryAsU32, type U32 } from "@typeberry/numbers";
-import type { Gas, GasCounter, SmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import type { Gas, IGasCounter, SmallGas } from "@typeberry/pvm-interface";
 import { type RegisterIndex, tryAsRegisterIndex } from "@typeberry/pvm-interpreter/registers.js";
 import { asOpaqueType, type Opaque } from "@typeberry/utils";
-import type { IHostCallMemory } from "./host-call-memory.js";
-import type { IHostCallRegisters } from "./host-call-registers.js";
+import type { HostCallMemory } from "./host-call-memory.js";
+import type { HostCallRegisters } from "./host-call-registers.js";
 
 /** Strictly-typed host call index. */
 export type HostCallIndex = Opaque<U32, "HostCallIndex[U32]">;
@@ -34,9 +34,9 @@ export interface HostCallHandler {
   /**
    * The gas cost of invocation of that host call.
    *
-   * NOTE: `((reg: IHostCallRegisters) => Gas)` function is for compatibility reasons: pre GP 0.7.2
+   * NOTE: `((reg: HostCallRegisters) => Gas)` function is for compatibility reasons: pre GP 0.7.2
    */
-  readonly basicGasCost: SmallGas | ((reg: IHostCallRegisters) => Gas);
+  readonly basicGasCost: SmallGas | ((reg: HostCallRegisters) => Gas);
 
   /** Currently executing service id. */
   readonly currentServiceId: U32;
@@ -49,5 +49,5 @@ export interface HostCallHandler {
    *
    * NOTE the call is ALLOWED and expected to modify registers and memory.
    */
-  execute(gas: GasCounter, regs: IHostCallRegisters, memory: IHostCallMemory): Promise<undefined | PvmExecution>;
+  execute(gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<undefined | PvmExecution>;
 }
diff --git a/packages/core/pvm-host-calls/host-call-memory.test.ts b/packages/core/pvm-host-calls/host-call-memory.test.ts
index 55803c70b..d906dbe14 100644
--- a/packages/core/pvm-host-calls/host-call-memory.test.ts
+++ b/packages/core/pvm-host-calls/host-call-memory.test.ts
@@ -1,17 +1,39 @@
 import { beforeEach, describe, it } from "node:test";
-import { tryAsU64 } from "@typeberry/numbers";
-import { Memory } from "@typeberry/pvm-interpreter";
-import { OutOfBounds, PageFault } from "@typeberry/pvm-interpreter/memory/errors.js";
-import { MEMORY_SIZE } from "@typeberry/pvm-interpreter/memory/memory-consts.js";
+import { tryAsU32, tryAsU64, type U32 } from "@typeberry/numbers";
+import {
+  getPageStartAddress,
+  type IMemory,
+  MAX_MEMORY_INDEX,
+  MEMORY_SIZE,
+  type PageFault,
+} from "@typeberry/pvm-interface";
 import { deepEqual, OK, Result } from "@typeberry/utils";
 import { HostCallMemory } from "./host-call-memory.js";
 
+class FakeMemory implements IMemory {
+  store(address: U32, bytes: Uint8Array): Result<OK, PageFault> {
+    const pageStart = getPageStartAddress(tryAsU32((address + bytes.length) % 2 ** 32));
+    return Result.error(
+      { address: tryAsU32(pageStart) },
+      () => `Page fault: attempted to access reserved page ${pageStart}`,
+    );
+  }
+
+  read(address: U32, result: Uint8Array): Result<OK, PageFault> {
+    const pageStart = getPageStartAddress(tryAsU32((address + result.length) % 2 ** 32));
+    return Result.error(
+      { address: tryAsU32(pageStart) },
+      () => `Page fault: attempted to access reserved page ${pageStart}`,
+    );
+  }
+}
+
 describe("HostCallMemory", () => {
-  let memory: Memory;
+  let memory: FakeMemory;
   let hostCallMemory: HostCallMemory;
 
   beforeEach(() => {
-    memory = new Memory();
+    memory = new FakeMemory();
     hostCallMemory = new HostCallMemory(memory);
   });
 
@@ -33,7 +55,7 @@ describe("HostCallMemory", () => {
 
       deepEqual(
         result,
-        Result.error(PageFault.fromPageNumber(0, true), () => "Page fault: attempted to access reserved page 0"),
+        Result.error({ address: tryAsU32(0) }, () => "Page fault: attempted to access reserved page 0"),
       );
     });
 
@@ -45,25 +67,19 @@ describe("HostCallMemory", () => {
 
       deepEqual(
         result,
-        Result.error(
-          new OutOfBounds(),
-          () => "Memory access out of bounds: address 4294967294 + length 3 exceeds memory size",
-        ),
+        Result.error({ address: tryAsU32(0) }, () => "Page fault: attempted to access reserved page 0"),
       );
     });
 
-    it("should throw when address exceeds MAX_MEMORY_INDEX", () => {
-      const address = tryAsU64(MEMORY_SIZE);
+    it("should wrap address when exceeds MAX_MEMORY_INDEX and throw", () => {
+      const address = tryAsU64(MAX_MEMORY_INDEX + 1);
       const bytes = new Uint8Array([1, 2, 3]);
 
       const res = hostCallMemory.storeFrom(address, bytes);
 
       deepEqual(
         res,
-        Result.error(
-          new OutOfBounds(),
-          () => "Memory access out of bounds: address 4294967296 + length 3 exceeds memory size",
-        ),
+        Result.error({ address: tryAsU32(0) }, () => "Page fault: attempted to access reserved page 0"),
       );
     });
   });
@@ -86,7 +102,7 @@ describe("HostCallMemory", () => {
 
       deepEqual(
         result,
-        Result.error(PageFault.fromPageNumber(0, true), () => "Page fault: attempted to access reserved page 0"),
+        Result.error({ address: tryAsU32(0) }, () => "Page fault: attempted to access reserved page 0"),
       );
     });
 
@@ -98,25 +114,19 @@ describe("HostCallMemory", () => {
 
       deepEqual(
         res,
-        Result.error(
-          new OutOfBounds(),
-          () => "Memory access out of bounds: address 4294967294 + length 3 exceeds memory size",
-        ),
+        Result.error({ address: tryAsU32(0) }, () => "Page fault: attempted to access reserved page 0"),
       );
     });
 
-    it("should throw when address exceeds MAX_MEMORY_INDEX", () => {
-      const address = tryAsU64(MEMORY_SIZE);
+    it("should wrap address when exceeds MAX_MEMORY_INDEX and throw", () => {
+      const address = tryAsU64(MAX_MEMORY_INDEX + 1);
       const result = new Uint8Array([1, 2, 3]);
 
       const res = hostCallMemory.loadInto(result, address);
 
       deepEqual(
         res,
-        Result.error(
-          new OutOfBounds(),
-          () => "Memory access out of bounds: address 4294967296 + length 3 exceeds memory size",
-        ),
+        Result.error({ address: tryAsU32(0) }, () => "Page fault: attempted to access reserved page 0"),
       );
     });
   });
diff --git a/packages/core/pvm-host-calls/host-call-memory.ts b/packages/core/pvm-host-calls/host-call-memory.ts
index 50dbde622..cf7e54e97 100644
--- a/packages/core/pvm-host-calls/host-call-memory.ts
+++ b/packages/core/pvm-host-calls/host-call-memory.ts
@@ -1,44 +1,43 @@
-import { tryAsU64, type U64 } from "@typeberry/numbers";
-import { type Memory, tryAsMemoryIndex } from "@typeberry/pvm-interpreter";
-import { OutOfBounds, type PageFault } from "@typeberry/pvm-interpreter/memory/errors.js";
-import { MEMORY_SIZE } from "@typeberry/pvm-interpreter/memory/memory-consts.js";
+import { tryAsU32, type U64 } from "@typeberry/numbers";
+import type { IMemory, PageFault } from "@typeberry/pvm-interface";
 import { OK, Result } from "@typeberry/utils";
 
-export interface IHostCallMemory {
-  storeFrom(address: U64, bytes: Uint8Array): Result<OK, PageFault | OutOfBounds>;
-  loadInto(result: Uint8Array, startAddress: U64): Result<OK, PageFault | OutOfBounds>;
-}
-
-export class HostCallMemory implements IHostCallMemory {
-  constructor(private readonly memory: Memory) {}
+export class HostCallMemory {
+  constructor(private readonly memory: IMemory) {}
 
-  storeFrom(address: U64, bytes: Uint8Array): Result<OK, PageFault | OutOfBounds> {
+  /**
+   * Save some bytes into memory under given address.
+   *
+   * NOTE: Given address is U64 (pure register value),
+   * but we use only lower 32-bits.
+   */
+  storeFrom(regAddress: U64, bytes: Uint8Array): Result<OK, PageFault> {
     if (bytes.length === 0) {
       return Result.ok(OK);
     }
 
-    if (address + tryAsU64(bytes.length) > MEMORY_SIZE) {
-      return Result.error(
-        new OutOfBounds(),
-        () => `Memory access out of bounds: address ${address} + length ${bytes.length} exceeds memory size`,
-      );
-    }
-
-    return this.memory.storeFrom(tryAsMemoryIndex(Number(address)), bytes);
+    // NOTE: We always take lower 32 bits from register value.
+    //
+    // https://graypaper.fluffylabs.dev/#/ab2cdbd/25ed0025ed00?v=0.7.2
+    const address = tryAsU32(Number(regAddress & 0xffff_ffffn));
+    return this.memory.store(address, bytes);
   }
 
-  loadInto(result: Uint8Array, startAddress: U64): Result<OK, PageFault | OutOfBounds> {
-    if (result.length === 0) {
+  /**
+   * Read some bytes from memory under given address.
+   *
+   * NOTE: Given address is U64 (pure register value),
+   * but we use only lower 32-bits.
+   */
+  loadInto(output: Uint8Array, regAddress: U64): Result<OK, PageFault> {
+    if (output.length === 0) {
       return Result.ok(OK);
     }
 
-    if (startAddress + tryAsU64(result.length) > MEMORY_SIZE) {
-      return Result.error(
-        new OutOfBounds(),
-        () => `Memory access out of bounds: address ${startAddress} + length ${result.length} exceeds memory size`,
-      );
-    }
-
-    return this.memory.loadInto(result, tryAsMemoryIndex(Number(startAddress)));
+    // https://graypaper.fluffylabs.dev/#/ab2cdbd/25ed0025ed00?v=0.7.2
+    //
+    // NOTE we are taking the the lower U32 part of the register, hence it's safe.
+    const address = tryAsU32(Number(regAddress & 0xffff_ffffn));
+    return this.memory.read(address, output);
   }
 }
diff --git a/packages/core/pvm-host-calls/host-call-registers.test.ts b/packages/core/pvm-host-calls/host-call-registers.test.ts
index 8bf79dce0..7b0ae56ce 100644
--- a/packages/core/pvm-host-calls/host-call-registers.test.ts
+++ b/packages/core/pvm-host-calls/host-call-registers.test.ts
@@ -2,25 +2,26 @@ import assert from "node:assert";
 import { describe, it } from "node:test";
 
 import { tryAsU64 } from "@typeberry/numbers";
-import { Registers } from "@typeberry/pvm-interpreter";
 import { HostCallRegisters } from "./host-call-registers.js";
 
 describe("HostCallRegisters", () => {
-  describe("get", () => {
+  describe("getAllEncoded", () => {
     it("reads a u64 value from the underlying registers", () => {
-      const registers = new Registers();
-      registers.setU64(0, tryAsU64(0xffff_ffff_ffff_fffdn));
-      const hostCallRegisters = new HostCallRegisters(registers);
+      const regs = new BigUint64Array(13);
+      regs[0] = 0xffff_ffff_ffff_fffdn;
+      const hostCallRegisters = new HostCallRegisters(new Uint8Array(regs.buffer));
       assert.strictEqual(hostCallRegisters.get(0), tryAsU64(0xffff_ffff_ffff_fffdn));
     });
   });
 
-  describe("set", () => {
+  describe("setAllEncoded", () => {
     it("writes a u64 value to the underlying registers", () => {
-      const registers = new Registers();
-      const hostCallRegisters = new HostCallRegisters(registers);
+      const regs = new BigUint64Array(13);
+      const hostCallRegisters = new HostCallRegisters(new Uint8Array(regs.buffer));
       hostCallRegisters.set(0, tryAsU64(0xffff_ffff_ffff_fffdn));
-      assert.strictEqual(registers.getU64(0), tryAsU64(0xffff_ffff_ffff_fffdn));
+      const view = new DataView(hostCallRegisters.getEncoded().buffer);
+      assert.strictEqual(view.getBigUint64(0, true), tryAsU64(0xffff_ffff_ffff_fffdn));
+      assert.strictEqual(regs[0], tryAsU64(0xffff_ffff_ffff_fffdn));
     });
   });
 });
diff --git a/packages/core/pvm-host-calls/host-call-registers.ts b/packages/core/pvm-host-calls/host-call-registers.ts
index d56cbf1b5..579973eb8 100644
--- a/packages/core/pvm-host-calls/host-call-registers.ts
+++ b/packages/core/pvm-host-calls/host-call-registers.ts
@@ -1,19 +1,25 @@
 import { tryAsU64, type U64 } from "@typeberry/numbers";
-import type { Registers } from "@typeberry/pvm-interpreter";
+import { REGISTER_BYTE_SIZE } from "@typeberry/pvm-interface";
 
-export interface IHostCallRegisters {
-  get(registerIndex: number): U64;
-  set(registerIndex: number, value: U64): void;
-}
+export class HostCallRegisters {
+  private readonly registers: DataView;
 
-export class HostCallRegisters implements IHostCallRegisters {
-  constructor(private readonly registers: Registers) {}
+  constructor(private readonly bytes: Uint8Array) {
+    this.registers = new DataView(bytes.buffer, bytes.byteOffset, bytes.byteLength);
+  }
 
+  /** Get U64 register value. */
   get(registerIndex: number): U64 {
-    return tryAsU64(this.registers.getU64(registerIndex));
+    return tryAsU64(this.registers.getBigUint64(registerIndex * REGISTER_BYTE_SIZE, true));
   }
 
+  /** Set U64 register value. */
   set(registerIndex: number, value: U64) {
-    this.registers.setU64(registerIndex, value);
+    this.registers.setBigUint64(registerIndex * REGISTER_BYTE_SIZE, value, true);
+  }
+
+  /** Get all registers encoded into little-endian bytes. */
+  getEncoded(): Uint8Array {
+    return this.bytes;
   }
 }
diff --git a/packages/core/pvm-host-calls/host-calls-manager.ts b/packages/core/pvm-host-calls/host-calls-manager.ts
index 8eb211a17..f2a6cef75 100644
--- a/packages/core/pvm-host-calls/host-calls-manager.ts
+++ b/packages/core/pvm-host-calls/host-calls-manager.ts
@@ -1,6 +1,6 @@
 import { Logger } from "@typeberry/logger";
 import { tryAsU32 } from "@typeberry/numbers";
-import { type Gas, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type Gas, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { check } from "@typeberry/utils";
 import {
   type HostCallHandler,
@@ -8,7 +8,7 @@ import {
   type PvmExecution,
   tryAsHostCallIndex,
 } from "./host-call-handler.js";
-import type { IHostCallRegisters } from "./host-call-registers.js";
+import type { HostCallRegisters } from "./host-call-registers.js";
 
 const logger = Logger.new(import.meta.filename, "host-calls-pvm");
 
@@ -41,7 +41,7 @@ export class HostCallsManager {
     context: string,
     hostCallIndex: HostCallIndex,
     hostCallHandler: HostCallHandler,
-    registers: IHostCallRegisters,
+    registers: HostCallRegisters,
     gas: Gas,
   ) {
     const { currentServiceId } = hostCallHandler;
diff --git a/packages/core/pvm-host-calls/host-calls.ts b/packages/core/pvm-host-calls/host-calls.ts
index 863a210a0..1317941f0 100644
--- a/packages/core/pvm-host-calls/host-calls.ts
+++ b/packages/core/pvm-host-calls/host-calls.ts
@@ -1,8 +1,4 @@
-import type { Interpreter, Memory } from "@typeberry/pvm-interpreter";
-import type { Gas } from "@typeberry/pvm-interpreter/gas.js";
-import { tryAsMemoryIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
-import type { Registers } from "@typeberry/pvm-interpreter/registers.js";
-import { Status } from "@typeberry/pvm-interpreter/status.js";
+import { type Gas, type IPvmInterpreter, Status } from "@typeberry/pvm-interface";
 import { assertNever, check, safeAllocUint8Array } from "@typeberry/utils";
 import { PvmExecution, tryAsHostCallIndex } from "./host-call-handler.js";
 import { HostCallMemory } from "./host-call-memory.js";
@@ -44,21 +40,22 @@ export class HostCalls {
     private hostCalls: HostCallsManager,
   ) {}
 
-  private getReturnValue(status: Status, pvmInstance: Interpreter): ReturnValue {
-    const gasConsumed = pvmInstance.getGasConsumed();
+  private getReturnValue(status: Status, pvmInstance: IPvmInterpreter): ReturnValue {
+    const gasConsumed = pvmInstance.gas.used();
     if (status === Status.OOG) {
       return ReturnValue.fromStatus(gasConsumed, status);
     }
 
     if (status === Status.HALT) {
-      const memory = pvmInstance.getMemory();
-      const regs = pvmInstance.getRegisters();
-      const maybeAddress = regs.getLowerU32(7);
-      const maybeLength = regs.getLowerU32(8);
+      const regs = new HostCallRegisters(pvmInstance.registers.getAllEncoded());
+      const memory = new HostCallMemory(pvmInstance.memory);
+      const address = regs.get(7);
+      // NOTE we are taking the the lower U32 part of the register, hence it's safe.
+      const length = Number(regs.get(8) & 0xffff_ffffn);
 
-      const result = safeAllocUint8Array(maybeLength);
-      const startAddress = tryAsMemoryIndex(maybeAddress);
-      const loadResult = memory.loadInto(result, startAddress);
+      const result = safeAllocUint8Array(length);
+
+      const loadResult = memory.loadInto(result, address);
 
       if (loadResult.isError) {
         return ReturnValue.fromMemorySlice(gasConsumed, new Uint8Array());
@@ -70,7 +67,7 @@ export class HostCalls {
     return ReturnValue.fromStatus(gasConsumed, Status.PANIC);
   }
 
-  private async execute(pvmInstance: Interpreter) {
+  private async execute(pvmInstance: IPvmInterpreter) {
     pvmInstance.runProgram();
     for (;;) {
       let status = pvmInstance.getStatus();
@@ -82,9 +79,9 @@ export class HostCalls {
         "We know that the exit param is not null, because the status is 'Status.HOST'
       `;
       const hostCallIndex = pvmInstance.getExitParam() ?? -1;
-      const gas = pvmInstance.getGasCounter();
-      const regs = new HostCallRegisters(pvmInstance.getRegisters());
-      const memory = new HostCallMemory(pvmInstance.getMemory());
+      const gas = pvmInstance.gas;
+      const regs = new HostCallRegisters(pvmInstance.registers.getAllEncoded());
+      const memory = new HostCallMemory(pvmInstance.memory);
       const index = tryAsHostCallIndex(hostCallIndex);
 
       const hostCall = this.hostCalls.get(index);
@@ -97,7 +94,7 @@ export class HostCalls {
       const pcLog = `[PC: ${pvmInstance.getPC()}]`;
       if (underflow) {
         this.hostCalls.traceHostCall(`${pcLog} OOG`, index, hostCall, regs, gas.get());
-        return ReturnValue.fromStatus(pvmInstance.getGasConsumed(), Status.OOG);
+        return ReturnValue.fromStatus(gas.used(), Status.OOG);
       }
       this.hostCalls.traceHostCall(`${pcLog} Invoking`, index, hostCall, regs, gasBefore);
       const result = await hostCall.execute(gas, regs, memory);
@@ -108,6 +105,7 @@ export class HostCalls {
         regs,
         gas.get(),
       );
+      pvmInstance.registers.setAllEncoded(regs.getEncoded());
 
       if (result === PvmExecution.Halt) {
         status = Status.HALT;
@@ -134,15 +132,9 @@ export class HostCalls {
     }
   }
 
-  async runProgram(
-    rawProgram: Uint8Array,
-    initialPc: number,
-    initialGas: Gas,
-    maybeRegisters?: Registers,
-    maybeMemory?: Memory,
-  ): Promise<ReturnValue> {
+  async runProgram(program: Uint8Array, args: Uint8Array, initialPc: number, initialGas: Gas): Promise<ReturnValue> {
     const pvmInstance = await this.pvmInstanceManager.getInstance();
-    pvmInstance.reset(rawProgram, initialPc, initialGas, maybeRegisters, maybeMemory);
+    pvmInstance.resetJam(program, args, initialPc, initialGas);
     try {
       return await this.execute(pvmInstance);
     } finally {
diff --git a/packages/core/pvm-host-calls/index.ts b/packages/core/pvm-host-calls/index.ts
index 564a83493..ea208a1da 100644
--- a/packages/core/pvm-host-calls/index.ts
+++ b/packages/core/pvm-host-calls/index.ts
@@ -1,6 +1,6 @@
 export { type HostCallHandler, PvmExecution, traceRegisters, tryAsHostCallIndex } from "./host-call-handler.js";
-export { HostCallMemory, type IHostCallMemory } from "./host-call-memory.js";
-export { HostCallRegisters, type IHostCallRegisters } from "./host-call-registers.js";
+export { HostCallMemory } from "./host-call-memory.js";
+export { HostCallRegisters } from "./host-call-registers.js";
 export { HostCalls as PvmHostCallExtension } from "./host-calls.js";
 export { HostCallsManager as HostCalls } from "./host-calls-manager.js";
 export { InterpreterInstanceManager as PvmInstanceManager } from "./interpreter-instance-manager.js";
diff --git a/packages/core/pvm-host-calls/interpreter-instance-manager.ts b/packages/core/pvm-host-calls/interpreter-instance-manager.ts
index 852dc3e62..b55b73a69 100644
--- a/packages/core/pvm-host-calls/interpreter-instance-manager.ts
+++ b/packages/core/pvm-host-calls/interpreter-instance-manager.ts
@@ -1,22 +1,37 @@
+import { PvmBackend } from "@typeberry/config";
+import type { IPvmInterpreter } from "@typeberry/pvm-interface";
 import { Interpreter } from "@typeberry/pvm-interpreter";
+import { AnanasInterpreter } from "@typeberry/pvm-interpreter-ananas";
+import { assertNever } from "@typeberry/utils";
 
-type ResolveFn = (pvm: Interpreter) => void;
+type ResolveFn = (pvm: IPvmInterpreter) => void;
 
+// TODO [MaSo] Delete this & also make host calls independent from intepreters.
 export class InterpreterInstanceManager {
-  private instances: Interpreter[] = [];
   private waitingQueue: ResolveFn[] = [];
 
-  constructor(noOfPvmInstances: number) {
-    for (let i = 0; i < noOfPvmInstances; i++) {
-      this.instances.push(
-        new Interpreter({
-          useSbrkGas: false,
-        }),
-      );
+  private constructor(private readonly instances: IPvmInterpreter[]) {}
+
+  static async new(interpreter: PvmBackend): Promise<InterpreterInstanceManager> {
+    const instances: IPvmInterpreter[] = [];
+    switch (interpreter) {
+      case PvmBackend.BuiltIn:
+        instances.push(
+          new Interpreter({
+            useSbrkGas: false,
+          }),
+        );
+        break;
+      case PvmBackend.Ananas:
+        instances.push(await AnanasInterpreter.new());
+        break;
+      default:
+        assertNever(interpreter);
     }
+    return new InterpreterInstanceManager(instances);
   }
 
-  async getInstance(): Promise<Interpreter> {
+  async getInstance(): Promise<IPvmInterpreter> {
     const instance = this.instances.pop();
     if (instance !== undefined) {
       return Promise.resolve(instance);
@@ -26,7 +41,7 @@ export class InterpreterInstanceManager {
     });
   }
 
-  releaseInstance(pvm: Interpreter) {
+  releaseInstance(pvm: IPvmInterpreter) {
     const waiting = this.waitingQueue.shift();
     if (waiting !== undefined) {
       return waiting(pvm);
diff --git a/packages/core/pvm-host-calls/package.json b/packages/core/pvm-host-calls/package.json
index 06d11f25e..d45f5ce34 100644
--- a/packages/core/pvm-host-calls/package.json
+++ b/packages/core/pvm-host-calls/package.json
@@ -4,9 +4,12 @@
   "description": "PVM host calls",
   "main": "index.ts",
   "dependencies": {
+    "@typeberry/config": "^0.2.0",
     "@typeberry/logger": "*",
     "@typeberry/numbers": "*",
+    "@typeberry/pvm-interface": "*",
     "@typeberry/pvm-interpreter": "*",
+    "@typeberry/pvm-interpreter-ananas": "*",
     "@typeberry/pvm-program": "*",
     "@typeberry/pvm-spi-decoder": "*",
     "@typeberry/utils": "*"
diff --git a/packages/core/pvm-interface/gas.ts b/packages/core/pvm-interface/gas.ts
new file mode 100644
index 000000000..8da1fb467
--- /dev/null
+++ b/packages/core/pvm-interface/gas.ts
@@ -0,0 +1,57 @@
+import { tryAsU32, tryAsU64, type U32, type U64 } from "@typeberry/numbers";
+import { asOpaqueType, type Opaque } from "@typeberry/utils";
+
+/** A U64 version of `Gas`. */
+export type BigGas = Opaque<U64, "BigGas[U64]">;
+/** A U32 version of `Gas`. */
+export type SmallGas = Opaque<U32, "SmallGas[U32]">;
+/** Gas measuring type. Can be either U64 or U32 for performance reasons. */
+export type Gas = BigGas | SmallGas;
+
+/** Attempt to convert given number into U32 gas representation. */
+export const tryAsSmallGas = (v: number): SmallGas => asOpaqueType(tryAsU32(v));
+
+/** Attempt to convert given number into U64 gas representation. */
+export const tryAsBigGas = (v: number | bigint): BigGas => asOpaqueType(tryAsU64(v));
+
+/** Attempt to convert given number into gas. */
+export const tryAsGas = (v: number | bigint): Gas =>
+  typeof v === "number" && v < 2 ** 32 ? tryAsSmallGas(v) : tryAsBigGas(v);
+
+/** An abstraction over gas counter.
+ *
+ * It can be optimized to use numbers instead of bigint in case of small gas.
+ */
+export interface IGasCounter {
+  /**
+   * Set during initialization of GasCounter.
+   *
+   * NOTE: Needed to calculate `used()` gas.
+   */
+  initialGas: Gas;
+
+  /** Return remaining gas. */
+  get(): Gas;
+
+  /**
+   * Overwrite remaining gas.
+   *
+   * NOTE: Could cause `used()` gas calculation to be incorrect.
+   *
+   * @see
+   * Prefer sub method instead.
+   */
+  set(g: Gas): void;
+
+  /** Returns true if there was an underflow. */
+  sub(g: Gas): boolean;
+
+  /**
+   * Calculates used gas since creation of GasCounter.
+   *
+   * The interface does not handle negative or more than `initialGas` values.
+   *
+   * NOTE: We can use at most `initialGas` and as little as `0`.
+   */
+  used(): Gas;
+}
diff --git a/packages/core/pvm-interface/index.ts b/packages/core/pvm-interface/index.ts
new file mode 100644
index 000000000..91870781e
--- /dev/null
+++ b/packages/core/pvm-interface/index.ts
@@ -0,0 +1,5 @@
+export * from "./gas.js";
+export * from "./memory.js";
+export * from "./pvm.js";
+export * from "./registers.js";
+export * from "./status.js";
diff --git a/packages/core/pvm-interface/memory.ts b/packages/core/pvm-interface/memory.ts
new file mode 100644
index 000000000..c978c2f32
--- /dev/null
+++ b/packages/core/pvm-interface/memory.ts
@@ -0,0 +1,24 @@
+import { tryAsU32, type U32 } from "@typeberry/numbers";
+import type { OK, Result } from "@typeberry/utils";
+
+export const MAX_MEMORY_INDEX = 0xffff_ffff;
+export const MEMORY_SIZE = MAX_MEMORY_INDEX + 1;
+
+const PAGE_SIZE_SHIFT = 12;
+
+export type PageFault = {
+  address: U32;
+};
+
+export function getPageStartAddress(address: U32): U32 {
+  return tryAsU32(((address >>> PAGE_SIZE_SHIFT) << PAGE_SIZE_SHIFT) >>> 0);
+}
+
+/** Allows store and read segments of memory. */
+export interface IMemory {
+  /** Store bytes into memory at given address. */
+  store(address: U32, bytes: Uint8Array): Result<OK, PageFault>;
+
+  /** Load bytes from memory from given address into given buffer. */
+  read(address: U32, result: Uint8Array): Result<OK, PageFault>;
+}
diff --git a/packages/core/pvm-interface/package.json b/packages/core/pvm-interface/package.json
new file mode 100644
index 000000000..45fc54414
--- /dev/null
+++ b/packages/core/pvm-interface/package.json
@@ -0,0 +1,17 @@
+{
+  "name": "@typeberry/pvm-interface",
+  "version": "0.1.3",
+  "description": "A PVM interface for external implementations.",
+  "main": "index.ts",
+  "dependencies": {
+    "@typeberry/numbers": "*",
+    "@typeberry/utils": "*"
+  },
+  "scripts": {
+    "start": "tsx ./bin.ts",
+    "test": "tsx --test $(find . -type f -name '*.test.ts' | tr '\\n' ' ')"
+  },
+  "author": "Fluffy Labs",
+  "license": "MPL-2.0",
+  "type": "module"
+}
diff --git a/packages/core/pvm-interface/pvm.ts b/packages/core/pvm-interface/pvm.ts
new file mode 100644
index 000000000..1d86ad2cb
--- /dev/null
+++ b/packages/core/pvm-interface/pvm.ts
@@ -0,0 +1,31 @@
+import type { U32 } from "@typeberry/numbers";
+import type { Gas, IGasCounter } from "./gas.js";
+import type { IMemory } from "./memory.js";
+import type { IRegisters } from "./registers.js";
+import type { Status } from "./status.js";
+
+export interface IPvmInterpreter {
+  /** Manipulate gas. */
+  readonly gas: IGasCounter;
+
+  /** Manipulate registers. */
+  readonly registers: IRegisters;
+
+  /** Manipulate memory. */
+  readonly memory: IMemory;
+
+  /** Prepare SPI program to be executed. */
+  resetJam(program: Uint8Array, args: Uint8Array, pc: number, gas: Gas): void;
+
+  /** Execute loaded program. */
+  runProgram(): void;
+
+  /** Get current Status. */
+  getStatus(): Status;
+
+  /** Get current Program Counter. */
+  getPC(): number;
+
+  /** Get exit args. Needed in case of HOST or FAULT. */
+  getExitParam(): U32 | null;
+}
diff --git a/packages/core/pvm-interface/registers.ts b/packages/core/pvm-interface/registers.ts
new file mode 100644
index 000000000..0e14cfc4d
--- /dev/null
+++ b/packages/core/pvm-interface/registers.ts
@@ -0,0 +1,18 @@
+export const NO_OF_REGISTERS = 13;
+export const REGISTER_BYTE_SIZE = 8;
+
+/** Allow to set and get all registers encoded into little-endian bytes. */
+export interface IRegisters {
+  /**
+   * Get all registers encoded into little-endian bytes.
+   *
+   * NOTE: Total length of bytes must be NO_OF_REGISTERS * REGISTER_BYTE_SIZE.
+   */
+  getAllEncoded(): Uint8Array;
+  /**
+   * Set all registers from little-endian encoded bytes.
+   *
+   * NOTE: Total length of bytes must be NO_OF_REGISTERS * REGISTER_BYTE_SIZE.
+   */
+  setAllEncoded(bytes: Uint8Array): void;
+}
diff --git a/packages/core/pvm-interface/status.ts b/packages/core/pvm-interface/status.ts
new file mode 100644
index 000000000..b04862cfd
--- /dev/null
+++ b/packages/core/pvm-interface/status.ts
@@ -0,0 +1,19 @@
+/**
+ * Result codes for the PVM execution.
+ *
+ * https://graypaper.fluffylabs.dev/#/ab2cdbd/2e43002e4300?v=0.7.2
+ */
+export enum Status {
+  /** Continue */
+  OK = 255,
+  /** Finished */
+  HALT = 0,
+  /** Panic */
+  PANIC = 1,
+  /** Page-fault */
+  FAULT = 2,
+  /** Host-call */
+  HOST = 3,
+  /** Out of gas */
+  OOG = 4,
+}
diff --git a/packages/core/pvm-interpreter-ananas/index.ts b/packages/core/pvm-interpreter-ananas/index.ts
new file mode 100644
index 000000000..d54467730
--- /dev/null
+++ b/packages/core/pvm-interpreter-ananas/index.ts
@@ -0,0 +1,181 @@
+import { readFileSync } from "node:fs";
+import { fileURLToPath } from "node:url";
+import { instantiate } from "@fluffylabs/anan-as/raw";
+import { tryAsU32, type U32 } from "@typeberry/numbers";
+import {
+  type Gas,
+  getPageStartAddress,
+  type IGasCounter,
+  type IMemory,
+  type IPvmInterpreter,
+  type IRegisters,
+  NO_OF_REGISTERS,
+  type PageFault,
+  REGISTER_BYTE_SIZE,
+  Status,
+  tryAsBigGas,
+  tryAsGas,
+} from "@typeberry/pvm-interface";
+import { check, OK, Result } from "@typeberry/utils";
+
+type Ananas = Awaited<ReturnType<typeof instantiate>>;
+
+// TODO [ToDr] Temporary solution. We need to inline WASM files for the final build.
+const wasmPath = fileURLToPath(new URL(import.meta.resolve("@fluffylabs/anan-as/release-mini.wasm"), import.meta.url));
+const wasmBuffer = readFileSync(wasmPath);
+
+// Max u32 value
+const INF_STEPS = 2 ** 32 - 1;
+
+class AnanasRegisters implements IRegisters {
+  constructor(private readonly instance: Ananas) {}
+
+  getAllEncoded(): Uint8Array {
+    return this.instance.getRegisters();
+  }
+
+  setAllEncoded(bytes: Uint8Array): void {
+    check`${bytes.length === NO_OF_REGISTERS * REGISTER_BYTE_SIZE}
+          Incorrect size of input registers. Got: ${bytes.length},
+          need: ${NO_OF_REGISTERS * REGISTER_BYTE_SIZE}`;
+    this.instance.setRegisters(lowerBytes(bytes));
+  }
+
+  getAllU64(): BigUint64Array {
+    const bytes = this.getAllEncoded();
+    return new BigUint64Array(bytes.buffer, bytes.byteOffset);
+  }
+}
+
+class AnanasMemory implements IMemory {
+  constructor(private readonly instance: Ananas) {}
+
+  store(address: U32, bytes: Uint8Array): Result<OK, PageFault> {
+    if (this.instance.setMemory(address, bytes)) {
+      return Result.ok(OK);
+    }
+    return Result.error({ address: getPageStartAddress(address) }, () => "Memory is unwritable!");
+  }
+
+  read(address: U32, result: Uint8Array): Result<OK, PageFault> {
+    if (result.length === 0) {
+      return Result.ok(OK);
+    }
+    const newResult = this.instance.getMemory(address, result.length);
+    if (newResult === null) {
+      return Result.error({ address: getPageStartAddress(address) }, () => "Memory is inaccessible!");
+    }
+    result.set(newResult, 0);
+    return Result.ok(OK);
+  }
+}
+
+class AnanasGasCounter implements IGasCounter {
+  initialGas: Gas = tryAsGas(0n);
+
+  constructor(private readonly instance: Ananas) {}
+
+  get(): Gas {
+    return tryAsGas(this.instance.getGasLeft());
+  }
+
+  set(g: Gas): void {
+    this.instance.setGasLeft(BigInt(g));
+  }
+
+  sub(g: Gas): boolean {
+    const result = this.instance.getGasLeft() - BigInt(g);
+    if (result >= 0n) {
+      this.instance.setGasLeft(result);
+      return false;
+    }
+    this.instance.setGasLeft(0n);
+    return true;
+  }
+
+  used(): Gas {
+    const gasConsumed = BigInt(this.initialGas) - BigInt(this.get());
+
+    if (gasConsumed < 0) {
+      return this.initialGas;
+    }
+
+    return tryAsBigGas(gasConsumed);
+  }
+}
+
+export class AnanasInterpreter implements IPvmInterpreter {
+  readonly registers: AnanasRegisters;
+  readonly memory: AnanasMemory;
+  readonly gas: AnanasGasCounter;
+
+  private constructor(private readonly instance: Ananas) {
+    this.registers = new AnanasRegisters(instance);
+    this.memory = new AnanasMemory(instance);
+    this.gas = new AnanasGasCounter(instance);
+  }
+
+  static async new() {
+    const wasmModule = await WebAssembly.compile(wasmBuffer);
+    const instance = await instantiate(wasmModule, {
+      env: {
+        abort: () => {
+          throw new Error("Abort called from WASM");
+        },
+      },
+    });
+    return new AnanasInterpreter(instance);
+  }
+
+  resetJam(program: Uint8Array, args: Uint8Array, pc: number, gas: Gas): void {
+    const programArr = lowerBytes(program);
+    const argsArr = lowerBytes(args);
+    this.gas.initialGas = gas;
+    this.instance.resetJAM(programArr, pc, BigInt(gas), argsArr, true);
+  }
+
+  resetGeneric(program: Uint8Array, _pc: number, gas: Gas): void {
+    const programArr = lowerBytes(program);
+    const emptyRegisters = Array(13 * 8).fill(0);
+    const pageMap = new Uint8Array();
+    const chunks = new Uint8Array();
+    this.gas.initialGas = gas;
+    this.instance.resetGenericWithMemory(programArr, emptyRegisters, pageMap, chunks, BigInt(gas), false);
+  }
+
+  nextStep(): boolean {
+    return this.instance.nextStep();
+  }
+
+  runProgram(): void {
+    // NOTE Setting max value u32 in nNextSteps making ananas running until finished
+    // without comming back and forth between JS <-> WASM
+    while (this.instance.nSteps(INF_STEPS)) {}
+  }
+
+  getStatus(): Status {
+    const status = this.instance.getStatus();
+    if (status < 0) {
+      return Status.OK;
+    }
+    check`${Status[status] !== undefined} Invalid status returned: ${status}`;
+    return status;
+  }
+
+  getPC(): number {
+    return this.instance.getProgramCounter();
+  }
+
+  getExitParam(): U32 | null {
+    return tryAsU32(this.instance.getExitArg());
+  }
+}
+
+/**  Convert `Uint8Array` to `number[]` */
+function lowerBytes(data: Uint8Array): number[] {
+  const r = new Array<number>(data.length);
+  for (let i = 0; i < data.length; i++) {
+    r[i] = data[i];
+  }
+  return r;
+}
diff --git a/packages/core/pvm-interpreter-ananas/package.json b/packages/core/pvm-interpreter-ananas/package.json
new file mode 100644
index 000000000..ffdbb25a3
--- /dev/null
+++ b/packages/core/pvm-interpreter-ananas/package.json
@@ -0,0 +1,21 @@
+{
+  "name": "@typeberry/pvm-interpreter-ananas",
+  "version": "0.1.3",
+  "description": "Anan-as PVM implementation.",
+  "main": "index.ts",
+  "dependencies": {
+    "@fluffylabs/anan-as": "^1.0.0-a9b8141",
+    "@typeberry/codec": "*",
+    "@typeberry/numbers": "*",
+    "@typeberry/pvm-interface": "*",
+    "@typeberry/utils": "*",
+    "assemblyscript-loader": "^0.3.0"
+  },
+  "scripts": {
+    "start": "tsx ./bin.ts",
+    "test": "tsx --test $(find . -type f -name '*.test.ts' | tr '\\n' ' ')"
+  },
+  "author": "Fluffy Labs",
+  "license": "MPL-2.0",
+  "type": "module"
+}
diff --git a/packages/core/pvm-interpreter/args-decoder/decoders/nibbles-decoder.ts b/packages/core/pvm-interpreter/args-decoder/decoders/nibbles-decoder.ts
index 5a2997668..cba051220 100644
--- a/packages/core/pvm-interpreter/args-decoder/decoders/nibbles-decoder.ts
+++ b/packages/core/pvm-interpreter/args-decoder/decoders/nibbles-decoder.ts
@@ -1,4 +1,4 @@
-import { NO_OF_REGISTERS } from "../../registers.js";
+import { NO_OF_REGISTERS } from "@typeberry/pvm-interface";
 
 const MAX_REGISTER_INDEX = NO_OF_REGISTERS - 1;
 const MAX_LENGTH = 4;
diff --git a/packages/core/pvm-interpreter/assemblify.ts b/packages/core/pvm-interpreter/assemblify.ts
index 398390163..384667bbf 100644
--- a/packages/core/pvm-interpreter/assemblify.ts
+++ b/packages/core/pvm-interpreter/assemblify.ts
@@ -1,4 +1,4 @@
-import { type SmallGas, tryAsSmallGas } from "./gas.js";
+import { type SmallGas, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { Instruction } from "./instruction.js";
 import type { Mask } from "./program-decoder/mask.js";
 
diff --git a/packages/core/pvm-interpreter/bin.ts b/packages/core/pvm-interpreter/bin.ts
index ca77e496e..8b5405288 100644
--- a/packages/core/pvm-interpreter/bin.ts
+++ b/packages/core/pvm-interpreter/bin.ts
@@ -1,4 +1,4 @@
-import { tryAsGas } from "./gas.js";
+import { tryAsGas } from "@typeberry/pvm-interface";
 import { Interpreter } from "./index.js";
 
 const program = new Uint8Array([
@@ -7,6 +7,6 @@ const program = new Uint8Array([
 ]);
 
 const pvm = new Interpreter();
-pvm.reset(program, 0, tryAsGas(1000));
+pvm.resetGeneric(program, 0, tryAsGas(1000));
 pvm.printProgram();
 pvm.runProgram();
diff --git a/packages/core/pvm-interpreter/gas.test.ts b/packages/core/pvm-interpreter/gas.test.ts
index 49031f25f..63aa74618 100644
--- a/packages/core/pvm-interpreter/gas.test.ts
+++ b/packages/core/pvm-interpreter/gas.test.ts
@@ -1,6 +1,7 @@
 import assert from "node:assert";
 import { describe, it } from "node:test";
-import { gasCounter, tryAsBigGas } from "./gas.js";
+import { tryAsBigGas, tryAsSmallGas } from "@typeberry/pvm-interface";
+import { gasCounter } from "./gas.js";
 
 describe("GasCounterU64", () => {
   it("should return false if there is no underflow", () => {
@@ -20,4 +21,33 @@ describe("GasCounterU64", () => {
     assert.strictEqual(underflow, true);
     assert.strictEqual(gas.get(), tryAsBigGas(0));
   });
+
+  it("should return correct gas consumed", () => {
+    const gasSubs = [tryAsSmallGas(10), tryAsSmallGas(15), tryAsSmallGas(20)];
+    const gas = gasCounter(tryAsBigGas(100));
+
+    // when
+    for (const g of gasSubs) {
+      gas.sub(g);
+    }
+
+    // then
+    assert.deepStrictEqual(gas.used(), tryAsBigGas(10 + 15 + 20));
+  });
+
+  it("should return cap to initial gas when consumed gas goes into negative", () => {
+    const initialGas = tryAsBigGas(100);
+    const gas = gasCounter(initialGas);
+    const gasCost = tryAsSmallGas(11);
+    const maxSteps = 10;
+    let i = 0;
+
+    // when
+    while (!gas.sub(gasCost) && i < maxSteps) {
+      i++;
+    }
+
+    // then
+    assert.deepStrictEqual(gas.used(), initialGas);
+  });
 });
diff --git a/packages/core/pvm-interpreter/gas.ts b/packages/core/pvm-interpreter/gas.ts
index 1dc6ca940..b2fc2a079 100644
--- a/packages/core/pvm-interpreter/gas.ts
+++ b/packages/core/pvm-interpreter/gas.ts
@@ -1,45 +1,17 @@
-import { tryAsU32, tryAsU64, type U32, type U64 } from "@typeberry/numbers";
-import { asOpaqueType, type Opaque } from "@typeberry/utils";
-
-/** Gas measuring type. Can be either U64 or U32 for performance reasons. */
-export type Gas = BigGas | SmallGas;
-/** A U64 version of `Gas`. */
-export type BigGas = Opaque<U64, "BigGas[U64]">;
-/** A U32 version of `Gas`. */
-export type SmallGas = Opaque<U32, "SmallGas[U32]">;
-
-/** Attempt to convert given number into U32 gas representation. */
-export const tryAsSmallGas = (v: number): SmallGas => asOpaqueType(tryAsU32(v));
-
-/** Attempt to convert given number into U64 gas representation. */
-export const tryAsBigGas = (v: number | bigint): BigGas => asOpaqueType(tryAsU64(v));
-
-/** Attempt to convert given number into gas. */
-export const tryAsGas = (v: number | bigint): Gas =>
-  typeof v === "number" && v < 2 ** 32 ? tryAsSmallGas(v) : tryAsBigGas(v);
+import { tryAsU64, type U64 } from "@typeberry/numbers";
+import { type Gas, type IGasCounter, tryAsGas } from "@typeberry/pvm-interface";
 
 /** Create a new gas counter instance depending on the gas value. */
-export function gasCounter(gas: Gas): GasCounter {
+export function gasCounter(gas: Gas): IGasCounter {
   return new GasCounterU64(tryAsU64(gas));
 }
 
-/** An abstraction over gas counter.
- *
- * It can be optimized to use numbers instead of bigint in case of small gas.
- */
-export interface GasCounter {
-  /** Return remaining gas. */
-  get(): Gas;
-
-  /** Overwrite remaining gas. Prefer sub method instead. */
-  set(g: Gas): void;
-
-  /** Returns true if there was an underflow. */
-  sub(g: Gas): boolean;
-}
+class GasCounterU64 implements IGasCounter {
+  initialGas: Gas;
 
-class GasCounterU64 implements GasCounter {
-  constructor(private gas: U64) {}
+  constructor(private gas: U64) {
+    this.initialGas = tryAsGas(gas);
+  }
 
   set(g: Gas) {
     this.gas = tryAsU64(g);
@@ -58,4 +30,15 @@ class GasCounterU64 implements GasCounter {
     this.gas = tryAsU64(0n);
     return true;
   }
+
+  used(): Gas {
+    const gasConsumed = tryAsU64(this.initialGas) - this.gas;
+
+    // In we have less than zero left we assume that all gas has been consumed.
+    if (gasConsumed < 0) {
+      return this.initialGas;
+    }
+
+    return tryAsGas(gasConsumed);
+  }
 }
diff --git a/packages/core/pvm-interpreter/index.ts b/packages/core/pvm-interpreter/index.ts
index bc2f9f57f..6bdfd9a80 100644
--- a/packages/core/pvm-interpreter/index.ts
+++ b/packages/core/pvm-interpreter/index.ts
@@ -1,13 +1,4 @@
-export {
-  type BigGas,
-  type Gas,
-  type GasCounter,
-  gasCounter,
-  type SmallGas,
-  tryAsBigGas,
-  tryAsGas,
-  tryAsSmallGas,
-} from "./gas.js";
+export { gasCounter } from "./gas.js";
 export * from "./interpreter.js";
 export {
   Memory,
diff --git a/packages/core/pvm-interpreter/instruction-gas-map.ts b/packages/core/pvm-interpreter/instruction-gas-map.ts
index 03036eb7d..9a24cc8d0 100644
--- a/packages/core/pvm-interpreter/instruction-gas-map.ts
+++ b/packages/core/pvm-interpreter/instruction-gas-map.ts
@@ -1,5 +1,5 @@
+import type { SmallGas } from "@typeberry/pvm-interface";
 import { byteToOpCodeMap } from "./assemblify.js";
-import type { SmallGas } from "./gas.js";
 import { HIGHEST_INSTRUCTION_NUMBER } from "./instruction.js";
 
 export const instructionGasMap = (() => {
diff --git a/packages/core/pvm-interpreter/interpreter.ts b/packages/core/pvm-interpreter/interpreter.ts
index d8ce22c29..ca560a3e0 100644
--- a/packages/core/pvm-interpreter/interpreter.ts
+++ b/packages/core/pvm-interpreter/interpreter.ts
@@ -1,12 +1,14 @@
 import { Logger } from "@typeberry/logger";
 import { tryAsU32, type U32 } from "@typeberry/numbers";
+import { type Gas, type IPvmInterpreter, Status, tryAsGas } from "@typeberry/pvm-interface";
+import { Program } from "@typeberry/pvm-program";
 import { ArgsDecoder } from "./args-decoder/args-decoder.js";
 import { createResults } from "./args-decoder/args-decoding-results.js";
 import { ArgumentType } from "./args-decoder/argument-type.js";
 import { instructionArgumentTypeMap } from "./args-decoder/instruction-argument-type-map.js";
 import { assemblify } from "./assemblify.js";
 import { BasicBlocks } from "./basic-blocks/index.js";
-import { type Gas, type GasCounter, gasCounter, tryAsBigGas, tryAsGas } from "./gas.js";
+import { gasCounter } from "./gas.js";
 import { Instruction } from "./instruction.js";
 import { instructionGasMap } from "./instruction-gas-map.js";
 import { InstructionResult } from "./instruction-result.js";
@@ -49,7 +51,6 @@ import { Mask } from "./program-decoder/mask.js";
 import { ProgramDecoder } from "./program-decoder/program-decoder.js";
 import { Registers } from "./registers.js";
 import { Result } from "./result.js";
-import { Status } from "./status.js";
 
 type InterpreterOptions = {
   useSbrkGas?: boolean;
@@ -57,14 +58,14 @@ type InterpreterOptions = {
 
 const logger = Logger.new(import.meta.filename, "pvm");
 
-export class Interpreter {
+export class Interpreter implements IPvmInterpreter {
   private readonly useSbrkGas: boolean;
-  private registers = new Registers();
+  readonly registers = new Registers();
+  readonly memory = new Memory();
+  gas = gasCounter(tryAsGas(0));
   private code: Uint8Array = new Uint8Array();
   private mask = Mask.empty();
   private pc = 0;
-  private gas = gasCounter(tryAsGas(0));
-  private initialGas = gasCounter(tryAsGas(0));
   private argsDecoder: ArgsDecoder;
   private threeRegsDispatcher: ThreeRegsDispatcher;
   private twoRegsOneImmDispatcher: TwoRegsOneImmDispatcher;
@@ -74,7 +75,6 @@ export class Interpreter {
   private oneOffsetDispatcher: OneOffsetDispatcher;
   private oneRegOneImmDispatcher: OneRegOneImmDispatcher;
   private instructionResult = new InstructionResult();
-  private memory = new Memory();
   private twoImmsDispatcher: TwoImmsDispatcher;
   private oneRegTwoImmsDispatcher: OneRegTwoImmsDispatcher;
   private noArgsDispatcher: NoArgsDispatcher;
@@ -128,7 +128,12 @@ export class Interpreter {
     this.oneRegOneExtImmDispatcher = new OneRegOneExtImmDispatcher(loadOps);
   }
 
-  reset(rawProgram: Uint8Array, pc: number, gas: Gas, maybeRegisters?: Registers, maybeMemory?: Memory) {
+  resetJam(program: Uint8Array, args: Uint8Array, pc: number, gas: Gas) {
+    const p = Program.fromSpi(program, args, true);
+    this.resetGeneric(p.code, pc, gas, p.registers, p.memory);
+  }
+
+  resetGeneric(rawProgram: Uint8Array, pc: number, gas: Gas, maybeRegisters?: Registers, maybeMemory?: Memory) {
     const programDecoder = new ProgramDecoder(rawProgram);
     this.code = programDecoder.getCode();
     this.mask = programDecoder.getMask();
@@ -136,7 +141,6 @@ export class Interpreter {
 
     this.pc = pc;
     this.gas = gasCounter(gas);
-    this.initialGas = gasCounter(gas);
     this.status = Status.OK;
     this.argsDecoder.reset(this.code, this.mask);
     this.basicBlocks.reset(this.code, this.mask);
@@ -278,10 +282,6 @@ export class Interpreter {
     return this.status;
   }
 
-  getRegisters() {
-    return this.registers;
-  }
-
   getPC() {
     return this.pc;
   }
@@ -290,24 +290,6 @@ export class Interpreter {
     this.pc = nextPc;
   }
 
-  getGas(): Gas {
-    return this.gas.get();
-  }
-
-  getGasConsumed(): Gas {
-    const gasConsumed = tryAsBigGas(this.initialGas.get()) - tryAsBigGas(this.gas.get());
-
-    if (gasConsumed < 0) {
-      return this.initialGas.get();
-    }
-
-    return tryAsBigGas(gasConsumed);
-  }
-
-  getGasCounter(): GasCounter {
-    return this.gas;
-  }
-
   getStatus() {
     return this.status;
   }
@@ -317,10 +299,6 @@ export class Interpreter {
     return p !== null ? tryAsU32(p) : p;
   }
 
-  getMemory() {
-    return this.memory;
-  }
-
   getMemoryPage(pageNumber: number): null | Uint8Array {
     return this.memory.getPageDump(tryAsPageNumber(pageNumber));
   }
diff --git a/packages/core/pvm-interpreter/memory/errors.ts b/packages/core/pvm-interpreter/memory/errors.ts
index 2f232c2c7..30a6de494 100644
--- a/packages/core/pvm-interpreter/memory/errors.ts
+++ b/packages/core/pvm-interpreter/memory/errors.ts
@@ -1,24 +1,25 @@
-import { MEMORY_SIZE } from "./memory-consts.js";
-import { type MemoryIndex, tryAsMemoryIndex } from "./memory-index.js";
+import { tryAsU32, type U32 } from "@typeberry/numbers";
+import { type PageFault as InterpreterPageFault, MEMORY_SIZE } from "@typeberry/pvm-interface";
+import { tryAsMemoryIndex } from "./memory-index.js";
 import { getStartPageIndex, getStartPageIndexFromPageNumber } from "./memory-utils.js";
 import { tryAsPageNumber } from "./pages/page-utils.js";
 
-export class PageFault {
+export class PageFault implements InterpreterPageFault {
   private constructor(
-    public address: MemoryIndex,
+    public address: U32,
     public isAccessFault = true,
   ) {}
 
   static fromPageNumber(maybePageNumber: number, isAccessFault = false) {
     const pageNumber = tryAsPageNumber(maybePageNumber);
     const startPageIndex = getStartPageIndexFromPageNumber(pageNumber);
-    return new PageFault(startPageIndex, isAccessFault);
+    return new PageFault(tryAsU32(startPageIndex), isAccessFault);
   }
 
   static fromMemoryIndex(maybeMemoryIndex: number, isAccessFault = false) {
     const memoryIndex = tryAsMemoryIndex(maybeMemoryIndex % MEMORY_SIZE);
     const startPageIndex = getStartPageIndex(memoryIndex);
-    return new PageFault(startPageIndex, isAccessFault);
+    return new PageFault(tryAsU32(startPageIndex), isAccessFault);
   }
 }
 
diff --git a/packages/core/pvm-interpreter/memory/memory-builder.test.ts b/packages/core/pvm-interpreter/memory/memory-builder.test.ts
index e06db96fc..3d960269c 100644
--- a/packages/core/pvm-interpreter/memory/memory-builder.test.ts
+++ b/packages/core/pvm-interpreter/memory/memory-builder.test.ts
@@ -1,8 +1,9 @@
 import assert from "node:assert";
 import { describe, it } from "node:test";
+import { MEMORY_SIZE } from "@typeberry/pvm-interface";
 import { IncorrectSbrkIndex } from "./errors.js";
 import { MemoryBuilder } from "./memory-builder.js";
-import { MEMORY_SIZE, PAGE_SIZE, RESERVED_NUMBER_OF_PAGES } from "./memory-consts.js";
+import { PAGE_SIZE, RESERVED_NUMBER_OF_PAGES } from "./memory-consts.js";
 import { tryAsMemoryIndex, tryAsSbrkIndex } from "./memory-index.js";
 import { ReadablePage, WriteablePage } from "./pages/index.js";
 import { tryAsPageNumber } from "./pages/page-utils.js";
diff --git a/packages/core/pvm-interpreter/memory/memory-consts.ts b/packages/core/pvm-interpreter/memory/memory-consts.ts
index 54b4fa398..f3ad96756 100644
--- a/packages/core/pvm-interpreter/memory/memory-consts.ts
+++ b/packages/core/pvm-interpreter/memory/memory-consts.ts
@@ -1,7 +1,6 @@
+import { MEMORY_SIZE } from "@typeberry/pvm-interface";
 import { check } from "@typeberry/utils";
 
-export const MAX_MEMORY_INDEX = 0xffff_ffff;
-export const MEMORY_SIZE = MAX_MEMORY_INDEX + 1;
 export const PAGE_SIZE_SHIFT = 12;
 // PAGE_SIZE has to be a power of 2
 export const PAGE_SIZE = 1 << PAGE_SIZE_SHIFT;
diff --git a/packages/core/pvm-interpreter/memory/memory-index.ts b/packages/core/pvm-interpreter/memory/memory-index.ts
index 31f0b6b22..bf999fa23 100644
--- a/packages/core/pvm-interpreter/memory/memory-index.ts
+++ b/packages/core/pvm-interpreter/memory/memory-index.ts
@@ -1,7 +1,6 @@
+import { MAX_MEMORY_INDEX } from "@typeberry/pvm-interface";
 import { asOpaqueType, check, type Opaque } from "@typeberry/utils";
 
-import { MAX_MEMORY_INDEX } from "./memory-consts.js";
-
 export type MemoryIndex = Opaque<number, "memory index">;
 
 export const tryAsMemoryIndex = (index: number): MemoryIndex => {
diff --git a/packages/core/pvm-interpreter/memory/memory-range.test.ts b/packages/core/pvm-interpreter/memory/memory-range.test.ts
index 18d91a8b9..1e3af2b8c 100644
--- a/packages/core/pvm-interpreter/memory/memory-range.test.ts
+++ b/packages/core/pvm-interpreter/memory/memory-range.test.ts
@@ -1,6 +1,7 @@
 import assert from "node:assert";
 import { describe, it } from "node:test";
-import { MEMORY_SIZE, PAGE_SIZE } from "./memory-consts.js";
+import { MEMORY_SIZE } from "@typeberry/pvm-interface";
+import { PAGE_SIZE } from "./memory-consts.js";
 import { tryAsMemoryIndex } from "./memory-index.js";
 import { MemoryRange } from "./memory-range.js";
 
diff --git a/packages/core/pvm-interpreter/memory/memory-range.ts b/packages/core/pvm-interpreter/memory/memory-range.ts
index 61b3bad5b..4ba38fefe 100644
--- a/packages/core/pvm-interpreter/memory/memory-range.ts
+++ b/packages/core/pvm-interpreter/memory/memory-range.ts
@@ -1,4 +1,5 @@
-import { MEMORY_SIZE, PAGE_SIZE, RESERVED_NUMBER_OF_PAGES } from "./memory-consts.js";
+import { MEMORY_SIZE } from "@typeberry/pvm-interface";
+import { PAGE_SIZE, RESERVED_NUMBER_OF_PAGES } from "./memory-consts.js";
 import { type MemoryIndex, tryAsMemoryIndex } from "./memory-index.js";
 
 /**
diff --git a/packages/core/pvm-interpreter/memory/memory-utils.test.ts b/packages/core/pvm-interpreter/memory/memory-utils.test.ts
index 54747525d..07a0ce608 100644
--- a/packages/core/pvm-interpreter/memory/memory-utils.test.ts
+++ b/packages/core/pvm-interpreter/memory/memory-utils.test.ts
@@ -1,7 +1,7 @@
 import assert from "node:assert";
 import { describe, it } from "node:test";
-
-import { MAX_MEMORY_INDEX, MEMORY_SIZE, PAGE_SIZE } from "./memory-consts.js";
+import { MAX_MEMORY_INDEX, MEMORY_SIZE } from "@typeberry/pvm-interface";
+import { PAGE_SIZE } from "./memory-consts.js";
 import { tryAsMemoryIndex, tryAsSbrkIndex } from "./memory-index.js";
 import { alignToPageSize, getPageNumber, getStartPageIndex, getStartPageIndexFromPageNumber } from "./memory-utils.js";
 import { tryAsPageNumber } from "./pages/page-utils.js";
diff --git a/packages/core/pvm-interpreter/memory/memory.test.ts b/packages/core/pvm-interpreter/memory/memory.test.ts
index 768c10a3e..1036f1d0d 100644
--- a/packages/core/pvm-interpreter/memory/memory.test.ts
+++ b/packages/core/pvm-interpreter/memory/memory.test.ts
@@ -1,10 +1,10 @@
 import assert from "node:assert";
 import { describe, it } from "node:test";
-
+import { MAX_MEMORY_INDEX } from "@typeberry/pvm-interface";
 import { deepEqual, OK, Result } from "@typeberry/utils";
 import { PageFault } from "./errors.js";
 import { Memory } from "./memory.js";
-import { MAX_MEMORY_INDEX, MIN_ALLOCATION_LENGTH, PAGE_SIZE, RESERVED_NUMBER_OF_PAGES } from "./memory-consts.js";
+import { MIN_ALLOCATION_LENGTH, PAGE_SIZE, RESERVED_NUMBER_OF_PAGES } from "./memory-consts.js";
 import { tryAsMemoryIndex, tryAsSbrkIndex } from "./memory-index.js";
 import { ReadablePage, WriteablePage } from "./pages/index.js";
 import type { MemoryPage } from "./pages/memory-page.js";
diff --git a/packages/core/pvm-interpreter/memory/memory.ts b/packages/core/pvm-interpreter/memory/memory.ts
index 805382bdc..13bb49853 100644
--- a/packages/core/pvm-interpreter/memory/memory.ts
+++ b/packages/core/pvm-interpreter/memory/memory.ts
@@ -1,9 +1,11 @@
 import { BytesBlob } from "@typeberry/bytes";
 import { Logger } from "@typeberry/logger";
+import type { U32 } from "@typeberry/numbers";
+import { type IMemory, type PageFault as InretpreterPageFault, MAX_MEMORY_INDEX } from "@typeberry/pvm-interface";
 import { OK, Result } from "@typeberry/utils";
 import { OutOfMemory, PageFault } from "./errors.js";
-import { MAX_MEMORY_INDEX, PAGE_SIZE, RESERVED_NUMBER_OF_PAGES } from "./memory-consts.js";
-import { type MemoryIndex, type SbrkIndex, tryAsSbrkIndex } from "./memory-index.js";
+import { PAGE_SIZE, RESERVED_NUMBER_OF_PAGES } from "./memory-consts.js";
+import { type MemoryIndex, type SbrkIndex, tryAsMemoryIndex, tryAsSbrkIndex } from "./memory-index.js";
 import { MemoryRange, RESERVED_MEMORY_RANGE } from "./memory-range.js";
 import { alignToPageSize, getPageNumber } from "./memory-utils.js";
 import { PageRange } from "./page-range.js";
@@ -24,7 +26,7 @@ enum AccessType {
 
 const logger = Logger.new(import.meta.filename, "pvm:mem");
 
-export class Memory {
+export class Memory implements IMemory {
   static fromInitialMemory(initialMemoryState: InitialMemoryState) {
     return new Memory(
       initialMemoryState?.sbrkIndex,
@@ -41,6 +43,14 @@ export class Memory {
     private memory = new Map<PageNumber, MemoryPage>(),
   ) {}
 
+  store(address: U32, bytes: Uint8Array): Result<OK, InretpreterPageFault> {
+    return this.storeFrom(tryAsMemoryIndex(address), bytes);
+  }
+
+  read(address: U32, output: Uint8Array): Result<OK, InretpreterPageFault> {
+    return this.loadInto(output, tryAsMemoryIndex(address));
+  }
+
   reset() {
     this.sbrkIndex = tryAsSbrkIndex(RESERVED_MEMORY_RANGE.end);
     this.virtualSbrkIndex = tryAsSbrkIndex(RESERVED_MEMORY_RANGE.end);
diff --git a/packages/core/pvm-interpreter/memory/page-range.test.ts b/packages/core/pvm-interpreter/memory/page-range.test.ts
index d79f0b4da..20640ed21 100644
--- a/packages/core/pvm-interpreter/memory/page-range.test.ts
+++ b/packages/core/pvm-interpreter/memory/page-range.test.ts
@@ -1,6 +1,7 @@
 import assert from "node:assert";
 import { describe, it } from "node:test";
-import { MAX_MEMORY_INDEX, MAX_NUMBER_OF_PAGES, MEMORY_SIZE, PAGE_SIZE } from "./memory-consts.js";
+import { MAX_MEMORY_INDEX, MEMORY_SIZE } from "@typeberry/pvm-interface";
+import { MAX_NUMBER_OF_PAGES, PAGE_SIZE } from "./memory-consts.js";
 import { tryAsMemoryIndex } from "./memory-index.js";
 import { MemoryRange } from "./memory-range.js";
 import { PageRange } from "./page-range.js";
diff --git a/packages/core/pvm-interpreter/ops/memory-ops.test.ts b/packages/core/pvm-interpreter/ops/memory-ops.test.ts
index 9adb517df..3f26628f0 100644
--- a/packages/core/pvm-interpreter/ops/memory-ops.test.ts
+++ b/packages/core/pvm-interpreter/ops/memory-ops.test.ts
@@ -1,8 +1,9 @@
 import assert from "node:assert";
 import { describe, it } from "node:test";
+import { MAX_MEMORY_INDEX } from "@typeberry/pvm-interface";
 import { InstructionResult } from "../instruction-result.js";
 import { Memory, MemoryBuilder } from "../memory/index.js";
-import { MAX_MEMORY_INDEX, PAGE_SIZE, RESERVED_NUMBER_OF_PAGES } from "../memory/memory-consts.js";
+import { PAGE_SIZE, RESERVED_NUMBER_OF_PAGES } from "../memory/memory-consts.js";
 import { tryAsMemoryIndex, tryAsSbrkIndex } from "../memory/memory-index.js";
 import { Registers } from "../registers.js";
 import { MemoryOps } from "./memory-ops.js";
diff --git a/packages/core/pvm-interpreter/ops/store-ops.ts b/packages/core/pvm-interpreter/ops/store-ops.ts
index b99b60b26..d90342d74 100644
--- a/packages/core/pvm-interpreter/ops/store-ops.ts
+++ b/packages/core/pvm-interpreter/ops/store-ops.ts
@@ -112,7 +112,7 @@ export class StoreOps {
       this.instructionResult.status = Result.FAULT_ACCESS;
     } else {
       this.instructionResult.status = Result.FAULT;
-      this.instructionResult.exitParam = getStartPageIndex(storeResult.error.address);
+      this.instructionResult.exitParam = getStartPageIndex(tryAsMemoryIndex(storeResult.error.address));
     }
   }
 }
diff --git a/packages/core/pvm-interpreter/package.json b/packages/core/pvm-interpreter/package.json
index 3d6daa452..dc6e8f8cd 100644
--- a/packages/core/pvm-interpreter/package.json
+++ b/packages/core/pvm-interpreter/package.json
@@ -8,6 +8,8 @@
     "@typeberry/codec": "*",
     "@typeberry/logger": "*",
     "@typeberry/numbers": "*",
+    "@typeberry/pvm-interface": "*",
+    "@typeberry/pvm-program": "*",
     "@typeberry/utils": "*"
   },
   "scripts": {
diff --git a/packages/core/pvm-interpreter/registers.test.ts b/packages/core/pvm-interpreter/registers.test.ts
index 56127bf4f..bc12c1d83 100644
--- a/packages/core/pvm-interpreter/registers.test.ts
+++ b/packages/core/pvm-interpreter/registers.test.ts
@@ -3,6 +3,7 @@ import { describe, it } from "node:test";
 import { Registers } from "./registers.js";
 
 const U32_BYTES = 4;
+const U64_BYTES = 8;
 
 describe("Registers", () => {
   describe("loading values", () => {
@@ -85,4 +86,58 @@ describe("Registers", () => {
       assert.deepStrictEqual(regs.getBytesAsLittleEndian(1, U32_BYTES), expectedBytes);
     });
   });
+
+  describe("Implemented IRegister", () => {
+    it("should correctly get all registers into bytes encoded", () => {
+      const regs = new Registers();
+
+      const num = 0xef_cd_ab_89_67_45_23_01n;
+      const bytesReg = new Uint8Array([0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef]);
+      const fill = new Uint8Array(12 * U64_BYTES).fill(0); // we set 1st register so we fill remaining 12 with 0
+      const expected = new Uint8Array([...bytesReg, ...fill]);
+
+      regs.setU64(0, num);
+
+      // when
+      const encodedAllRegisters = regs.getAllEncoded();
+
+      // then
+      assert.deepStrictEqual(encodedAllRegisters.length, expected.length);
+      assert.deepStrictEqual(encodedAllRegisters, expected);
+    });
+
+    it("should correctly set all registers from bytes encoded", () => {
+      const regs = new Registers();
+
+      const bytesReg = new Uint8Array([0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef]);
+      const fill = new Uint8Array(12 * U64_BYTES).fill(0); // we set 1st register so we fill remaining 12 with 0
+      const bytes = new Uint8Array([...bytesReg, ...fill]);
+
+      const expected = 0xef_cd_ab_89_67_45_23_01n;
+
+      regs.setAllEncoded(bytes);
+
+      const reg = regs.getU64(0);
+
+      assert.deepStrictEqual(reg, expected);
+    });
+
+    it("should throw when trying to set all registers from bytes encoded with incorrect size", () => {
+      const regs = new Registers();
+
+      const bytesReg = new Uint8Array([0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef]);
+      const fill = new Uint8Array(12 * U64_BYTES).fill(0); // we set 1st register so we fill remaining 12 with 0
+      const bytes = new Uint8Array([...bytesReg, ...fill, 0x00]);
+
+      // too many
+      assert.throws(() => {
+        regs.setAllEncoded(bytes);
+      });
+
+      // too little
+      assert.throws(() => {
+        regs.setAllEncoded(fill);
+      });
+    });
+  });
 });
diff --git a/packages/core/pvm-interpreter/registers.ts b/packages/core/pvm-interpreter/registers.ts
index 30a7de456..d3a64e0c9 100644
--- a/packages/core/pvm-interpreter/registers.ts
+++ b/packages/core/pvm-interpreter/registers.ts
@@ -1,7 +1,7 @@
+import { type IRegisters, NO_OF_REGISTERS } from "@typeberry/pvm-interface";
 import { asOpaqueType, check, type Opaque, safeAllocUint8Array } from "@typeberry/utils";
 
-export const NO_OF_REGISTERS = 13;
-const REGISTER_SIZE_SHIFT = 3;
+const REGISTER_SIZE_SHIFT = 3; // x << 3 === x * 8
 
 export type RegisterIndex = Opaque<number, "register index">;
 
@@ -10,7 +10,7 @@ export const tryAsRegisterIndex = (index: number): RegisterIndex => {
   return asOpaqueType(index);
 };
 
-export class Registers {
+export class Registers implements IRegisters {
   private asSigned: BigInt64Array;
   private asUnsigned: BigUint64Array;
 
@@ -20,6 +20,15 @@ export class Registers {
     this.asUnsigned = new BigUint64Array(bytes.buffer, bytes.byteOffset);
   }
 
+  getAllEncoded(): Uint8Array {
+    return this.bytes;
+  }
+
+  setAllEncoded(bytes: Uint8Array): void {
+    check`${bytes.length === this.bytes.length} Incorrect size of input registers. Got: ${bytes.length}, need: ${this.bytes.length}`;
+    this.bytes.set(bytes, 0);
+  }
+
   static fromBytes(bytes: Uint8Array) {
     check`${bytes.length === NO_OF_REGISTERS << REGISTER_SIZE_SHIFT} Invalid size of registers array.`;
     return new Registers(bytes);
@@ -30,10 +39,6 @@ export class Registers {
     return this.bytes.subarray(offset, offset + len);
   }
 
-  getAllBytesAsLittleEndian() {
-    return this.bytes;
-  }
-
   copyFrom(regs: Registers | BigUint64Array) {
     const array = regs instanceof BigUint64Array ? regs : regs.asUnsigned;
     this.asUnsigned.set(array);
diff --git a/packages/core/pvm-interpreter/status.ts b/packages/core/pvm-interpreter/status.ts
deleted file mode 100644
index e44dda2c5..000000000
--- a/packages/core/pvm-interpreter/status.ts
+++ /dev/null
@@ -1,13 +0,0 @@
-/**
- * Inner status codes for the PVM
- *
- * https://graypaper.fluffylabs.dev/#/85129da/2cae022cae02?v=0.6.3
- */
-export enum Status {
-  OK = 255,
-  HALT = 0,
-  PANIC = 1,
-  FAULT = 2,
-  HOST = 3,
-  OOG = 4,
-}
diff --git a/packages/jam/config-node/node-config.ts b/packages/jam/config-node/node-config.ts
index ec73bd827..d60ca9cf4 100644
--- a/packages/jam/config-node/node-config.ts
+++ b/packages/jam/config-node/node-config.ts
@@ -1,6 +1,7 @@
 import fs from "node:fs";
 import os from "node:os";
 import type { JsonObject } from "@typeberry/block-json";
+import { PvmBackend } from "@typeberry/config";
 import { configs } from "@typeberry/configs";
 import { type FromJson, json, parseFromJson } from "@typeberry/json-parser";
 import { Logger } from "@typeberry/logger";
@@ -18,6 +19,7 @@ export const DEFAULT_CONFIG = "default";
 export const NODE_DEFAULTS = {
   name: isBrowser() ? "browser" : os.hostname(),
   config: DEFAULT_CONFIG,
+  pvm: PvmBackend.BuiltIn,
 };
 
 /** Chain spec chooser. */
diff --git a/packages/jam/config/index.ts b/packages/jam/config/index.ts
index cb1cfaa47..4887e0122 100644
--- a/packages/jam/config/index.ts
+++ b/packages/jam/config/index.ts
@@ -1,2 +1,3 @@
 export * from "./chain-spec.js";
 export * from "./network.js";
+export * from "./pvm-backend.js";
diff --git a/packages/jam/config/pvm-backend.ts b/packages/jam/config/pvm-backend.ts
new file mode 100644
index 000000000..8e07a0ed5
--- /dev/null
+++ b/packages/jam/config/pvm-backend.ts
@@ -0,0 +1,10 @@
+/** Implemented PVM Backends names in THE SAME ORDER as enum. */
+export const PvmBackendNames = ["built-in", "ananas"];
+
+/** Implemented PVM Backends to choose from. */
+export enum PvmBackend {
+  /** Built-in aka. Typeberry 🫐 interpreter. */
+  BuiltIn = 0,
+  /** Ananas 🍍 interpreter. */
+  Ananas = 1,
+}
diff --git a/packages/jam/jam-host-calls/accumulate/assign.test.ts b/packages/jam/jam-host-calls/accumulate/assign.test.ts
index 205d8783b..44f6563f6 100644
--- a/packages/jam/jam-host-calls/accumulate/assign.test.ts
+++ b/packages/jam/jam-host-calls/accumulate/assign.test.ts
@@ -8,8 +8,8 @@ import { tinyChainSpec } from "@typeberry/config";
 import { type Blake2bHash, HASH_SIZE } from "@typeberry/hash";
 import { tryAsU64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import { Registers } from "@typeberry/pvm-interpreter";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter } from "@typeberry/pvm-interpreter/gas.js";
 import { MemoryBuilder, tryAsMemoryIndex } from "@typeberry/pvm-interpreter/memory/index.js";
 import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
@@ -18,6 +18,7 @@ import { Result } from "@typeberry/utils";
 import { UpdatePrivilegesError } from "../externalities/partial-state.js";
 import { PartialStateMock } from "../externalities/partial-state-mock.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Assign } from "./assign.js";
 
 const gas = gasCounter(tryAsGas(0));
@@ -32,7 +33,7 @@ function prepareRegsAndMemory(
   { skipAuthQueue = false, assigners = null }: { skipAuthQueue?: boolean; assigners?: bigint | number | null } = {},
 ) {
   const memStart = 2 ** 16;
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(CORE_INDEX_REG, tryAsU64(coreIndex));
   registers.set(AUTH_QUEUE_START_REG, tryAsU64(memStart));
   if (assigners !== null) {
@@ -52,10 +53,10 @@ function prepareRegsAndMemory(
   if (!skipAuthQueue) {
     builder.setReadablePages(tryAsMemoryIndex(memStart), tryAsMemoryIndex(memStart + PAGE_SIZE), data.raw);
   }
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/accumulate/assign.ts b/packages/jam/jam-host-calls/accumulate/assign.ts
index e4594229b..9437ddf09 100644
--- a/packages/jam/jam-host-calls/accumulate/assign.ts
+++ b/packages/jam/jam-host-calls/accumulate/assign.ts
@@ -3,9 +3,9 @@ import { codec, Decoder } from "@typeberry/codec";
 import { FixedSizeArray } from "@typeberry/collections";
 import type { ChainSpec } from "@typeberry/config";
 import { HASH_SIZE } from "@typeberry/hash";
-import type { HostCallHandler, IHostCallMemory, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { PvmExecution, traceRegisters, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { AUTHORIZATION_QUEUE_SIZE } from "@typeberry/state";
 import { assertNever, safeAllocUint8Array } from "@typeberry/utils";
 import { type PartialState, UpdatePrivilegesError } from "../externalities/partial-state.js";
@@ -31,11 +31,7 @@ export class Assign implements HostCallHandler {
     private readonly chainSpec: ChainSpec,
   ) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<undefined | PvmExecution> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<undefined | PvmExecution> {
     // c
     const maybeCoreIndex = regs.get(IN_OUT_REG);
     // o
diff --git a/packages/jam/jam-host-calls/accumulate/bless.test.ts b/packages/jam/jam-host-calls/accumulate/bless.test.ts
index d38504fff..013cf1c8a 100644
--- a/packages/jam/jam-host-calls/accumulate/bless.test.ts
+++ b/packages/jam/jam-host-calls/accumulate/bless.test.ts
@@ -5,8 +5,8 @@ import { codec, Encoder } from "@typeberry/codec";
 import { tinyChainSpec } from "@typeberry/config";
 import { tryAsU64, type U64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import { Registers } from "@typeberry/pvm-interpreter";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter } from "@typeberry/pvm-interpreter/gas.js";
 import { MemoryBuilder, tryAsMemoryIndex } from "@typeberry/pvm-interpreter/memory/index.js";
 import { PAGE_SIZE } from "@typeberry/pvm-interpreter/memory/memory-consts.js";
 import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
@@ -16,6 +16,7 @@ import { Compatibility, GpVersion, Result } from "@typeberry/utils";
 import { UpdatePrivilegesError } from "../externalities/partial-state.js";
 import { PartialStateMock } from "../externalities/partial-state-mock.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Bless } from "./bless.js";
 
 const gas = gasCounter(tryAsGas(0));
@@ -54,7 +55,7 @@ function prepareRegsAndMemory(
 ) {
   const memAuthStart = 2 ** 24;
   const memStart = 2 ** 16;
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(MANAGER_REG, manager ?? tryAsU64(5));
   registers.set(AUTHORIZATION_REG, tryAsU64(memAuthStart));
   registers.set(VALIDATOR_REG, validator ?? tryAsU64(20));
@@ -80,10 +81,10 @@ function prepareRegsAndMemory(
     builder.setReadablePages(tryAsMemoryIndex(memAuthStart), tryAsMemoryIndex(memAuthStart + PAGE_SIZE), dataAuth.raw);
   }
 
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 describe("HostCalls: Bless", () => {
diff --git a/packages/jam/jam-host-calls/accumulate/bless.ts b/packages/jam/jam-host-calls/accumulate/bless.ts
index a899d6a95..dce274e4a 100644
--- a/packages/jam/jam-host-calls/accumulate/bless.ts
+++ b/packages/jam/jam-host-calls/accumulate/bless.ts
@@ -2,9 +2,9 @@ import { type ServiceGas, type ServiceId, tryAsServiceGas, tryAsServiceId } from
 import { codec, Decoder, tryAsExactBytes } from "@typeberry/codec";
 import type { ChainSpec } from "@typeberry/config";
 import { tryAsU64 } from "@typeberry/numbers";
-import type { HostCallHandler, IHostCallMemory, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { PvmExecution, traceRegisters, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { tryAsPerCore } from "@typeberry/state";
 import { asOpaqueType, assertNever, Compatibility, GpVersion, safeAllocUint8Array } from "@typeberry/utils";
 import { type PartialState, UpdatePrivilegesError } from "../externalities/partial-state.js";
@@ -43,11 +43,7 @@ export class Bless implements HostCallHandler {
     private readonly chainSpec: ChainSpec,
   ) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<undefined | PvmExecution> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<undefined | PvmExecution> {
     // `m`: manager service (can change privileged services)
     const manager = getServiceId(regs.get(IN_OUT_REG));
     // `a`: manages authorization queue
diff --git a/packages/jam/jam-host-calls/accumulate/checkpoint.test.ts b/packages/jam/jam-host-calls/accumulate/checkpoint.test.ts
index 45cd95d4e..39b2476fa 100644
--- a/packages/jam/jam-host-calls/accumulate/checkpoint.test.ts
+++ b/packages/jam/jam-host-calls/accumulate/checkpoint.test.ts
@@ -2,9 +2,10 @@ import assert from "node:assert";
 import { describe, it } from "node:test";
 import { tryAsServiceId } from "@typeberry/block";
 import { HostCallRegisters } from "@typeberry/pvm-host-calls";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
-import { Registers } from "@typeberry/pvm-interpreter/registers.js";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter } from "@typeberry/pvm-interpreter/gas.js";
 import { PartialStateMock } from "../externalities/partial-state-mock.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Checkpoint } from "./checkpoint.js";
 
 const REGISTER = 7;
@@ -16,7 +17,7 @@ describe("HostCalls: Checkpoint", () => {
     const checkpoint = new Checkpoint(serviceId, accumulate);
 
     const counter = gasCounter(tryAsGas(2n ** 42n - 1n));
-    const regs = new HostCallRegisters(new Registers());
+    const regs = new HostCallRegisters(emptyRegistersBuffer());
 
     assert.deepStrictEqual(regs.get(REGISTER), 0n);
     assert.deepStrictEqual(accumulate.checkpointCalled, 0);
diff --git a/packages/jam/jam-host-calls/accumulate/checkpoint.ts b/packages/jam/jam-host-calls/accumulate/checkpoint.ts
index 96b662c31..a049315ba 100644
--- a/packages/jam/jam-host-calls/accumulate/checkpoint.ts
+++ b/packages/jam/jam-host-calls/accumulate/checkpoint.ts
@@ -1,7 +1,7 @@
 import type { ServiceId } from "@typeberry/block";
-import type { HostCallHandler, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { type PvmExecution, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import type { RegisterIndex } from "@typeberry/pvm-interpreter/registers.js";
 import type { PartialState } from "../externalities/partial-state.js";
 import { GasHostCall } from "../gas.js";
@@ -27,7 +27,7 @@ export class Checkpoint implements HostCallHandler {
     this.tracedRegisters = this.gasHostCall.tracedRegisters;
   }
 
-  async execute(gas: GasCounter, regs: IHostCallRegisters): Promise<undefined | PvmExecution> {
+  async execute(gas: IGasCounter, regs: HostCallRegisters): Promise<undefined | PvmExecution> {
     await this.gasHostCall.execute(gas, regs);
     this.partialState.checkpoint();
     logger.trace`CHECKPOINT()`;
diff --git a/packages/jam/jam-host-calls/accumulate/designate.test.ts b/packages/jam/jam-host-calls/accumulate/designate.test.ts
index 9fe733d44..e68da84de 100644
--- a/packages/jam/jam-host-calls/accumulate/designate.test.ts
+++ b/packages/jam/jam-host-calls/accumulate/designate.test.ts
@@ -7,16 +7,17 @@ import { tinyChainSpec } from "@typeberry/config";
 import { BANDERSNATCH_KEY_BYTES, BLS_KEY_BYTES, ED25519_KEY_BYTES } from "@typeberry/crypto";
 import { tryAsU64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter } from "@typeberry/pvm-interpreter/gas.js";
 import { MemoryBuilder, tryAsMemoryIndex } from "@typeberry/pvm-interpreter/memory/index.js";
 import { PAGE_SIZE } from "@typeberry/pvm-interpreter/memory/memory-consts.js";
 import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
-import { Registers } from "@typeberry/pvm-interpreter/registers.js";
 import { VALIDATOR_META_BYTES, ValidatorData } from "@typeberry/state";
 import { Result } from "@typeberry/utils";
 import { UnprivilegedError } from "../externalities/partial-state.js";
 import { PartialStateMock } from "../externalities/partial-state-mock.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Designate } from "./designate.js";
 
 const gas = gasCounter(tryAsGas(0));
@@ -28,7 +29,7 @@ function prepareRegsAndMemory(
   { skipValidators = false }: { skipValidators?: boolean } = {},
 ) {
   const memStart = 2 ** 16;
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(VALIDATORS_DATA_START_REG, tryAsU64(memStart));
 
   const builder = new MemoryBuilder();
@@ -51,10 +52,10 @@ function prepareRegsAndMemory(
   if (!skipValidators) {
     builder.setReadablePages(tryAsMemoryIndex(memStart), tryAsMemoryIndex(memStart + PAGE_SIZE), data.raw);
   }
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers: registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/accumulate/designate.ts b/packages/jam/jam-host-calls/accumulate/designate.ts
index df16ece91..ebc1523f3 100644
--- a/packages/jam/jam-host-calls/accumulate/designate.ts
+++ b/packages/jam/jam-host-calls/accumulate/designate.ts
@@ -1,9 +1,9 @@
 import { type ServiceId, tryAsPerValidator } from "@typeberry/block";
 import { Decoder, tryAsExactBytes } from "@typeberry/codec";
 import type { ChainSpec } from "@typeberry/config";
-import type { HostCallHandler, IHostCallMemory, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { PvmExecution, traceRegisters, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { ValidatorData } from "@typeberry/state";
 import { safeAllocUint8Array } from "@typeberry/utils";
 import type { PartialState } from "../externalities/partial-state.js";
@@ -29,11 +29,7 @@ export class Designate implements HostCallHandler {
     private readonly chainSpec: ChainSpec,
   ) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<undefined | PvmExecution> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<undefined | PvmExecution> {
     // `o`
     const validatorsStart = regs.get(IN_OUT_REG);
 
diff --git a/packages/jam/jam-host-calls/accumulate/eject.test.ts b/packages/jam/jam-host-calls/accumulate/eject.test.ts
index 4a33aa41b..2cc3350a7 100644
--- a/packages/jam/jam-host-calls/accumulate/eject.test.ts
+++ b/packages/jam/jam-host-calls/accumulate/eject.test.ts
@@ -5,16 +5,17 @@ import { Bytes } from "@typeberry/bytes";
 import { HASH_SIZE } from "@typeberry/hash";
 import { tryAsU64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
+import { tryAsGas } from "@typeberry/pvm-interface";
 import { MemoryBuilder } from "@typeberry/pvm-interpreter";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
+import { gasCounter } from "@typeberry/pvm-interpreter/gas.js";
 import { tryAsMemoryIndex } from "@typeberry/pvm-interpreter/memory/index.js";
 import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
-import { Registers } from "@typeberry/pvm-interpreter/registers.js";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
 import { deepEqual, OK, Result } from "@typeberry/utils";
 import { EjectError } from "../externalities/partial-state.js";
 import { PartialStateMock } from "../externalities/partial-state-mock.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Eject } from "./eject.js";
 
 const RESULT_REG = 7;
@@ -27,7 +28,7 @@ function prepareRegsAndMemory(
   { skipHash = false }: { skipHash?: boolean } = {},
 ) {
   const hashStart = 2 ** 16;
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(SOURCE_REG, tryAsU64(source));
   registers.set(HASH_START_REG, tryAsU64(hashStart));
 
@@ -36,10 +37,10 @@ function prepareRegsAndMemory(
     builder.setReadablePages(tryAsMemoryIndex(hashStart), tryAsMemoryIndex(hashStart + PAGE_SIZE), hash.raw);
   }
 
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/accumulate/eject.ts b/packages/jam/jam-host-calls/accumulate/eject.ts
index 45db683d0..a73d1958d 100644
--- a/packages/jam/jam-host-calls/accumulate/eject.ts
+++ b/packages/jam/jam-host-calls/accumulate/eject.ts
@@ -2,9 +2,9 @@ import type { ServiceId } from "@typeberry/block";
 import type { PreimageHash } from "@typeberry/block/preimage.js";
 import { Bytes } from "@typeberry/bytes";
 import { HASH_SIZE } from "@typeberry/hash";
-import type { HostCallHandler, IHostCallMemory, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { PvmExecution, traceRegisters, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { assertNever, resultToString } from "@typeberry/utils";
 import { EjectError, type PartialState } from "../externalities/partial-state.js";
 import { logger } from "../logger.js";
@@ -28,11 +28,7 @@ export class Eject implements HostCallHandler {
     private readonly partialState: PartialState,
   ) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<undefined | PvmExecution> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<undefined | PvmExecution> {
     // `d`: account to eject from (source)
     const serviceId = getServiceId(regs.get(IN_OUT_REG));
     // `o`: preimage hash start memory index
diff --git a/packages/jam/jam-host-calls/accumulate/forget.test.ts b/packages/jam/jam-host-calls/accumulate/forget.test.ts
index eb922f04d..dcd8ea1b0 100644
--- a/packages/jam/jam-host-calls/accumulate/forget.test.ts
+++ b/packages/jam/jam-host-calls/accumulate/forget.test.ts
@@ -5,8 +5,8 @@ import { Bytes } from "@typeberry/bytes";
 import { HASH_SIZE } from "@typeberry/hash";
 import { tryAsU64, type U64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import { Registers } from "@typeberry/pvm-interpreter";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter } from "@typeberry/pvm-interpreter/gas.js";
 import { MemoryBuilder, tryAsMemoryIndex } from "@typeberry/pvm-interpreter/memory/index.js";
 import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
@@ -14,6 +14,7 @@ import { Result } from "@typeberry/utils";
 import { ForgetPreimageError } from "../externalities/partial-state.js";
 import { PartialStateMock } from "../externalities/partial-state-mock.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Forget } from "./forget.js";
 
 const gas = gasCounter(tryAsGas(0));
@@ -27,7 +28,7 @@ function prepareRegsAndMemory(
   { skipPreimageHash = false }: { skipPreimageHash?: boolean } = {},
 ) {
   const memStart = 2 ** 16;
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(HASH_START_REG, tryAsU64(memStart));
   registers.set(LENGTH_REG, preimageLength);
 
@@ -36,10 +37,10 @@ function prepareRegsAndMemory(
   if (!skipPreimageHash) {
     builder.setReadablePages(tryAsMemoryIndex(memStart), tryAsMemoryIndex(memStart + PAGE_SIZE), preimageHash.raw);
   }
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/accumulate/forget.ts b/packages/jam/jam-host-calls/accumulate/forget.ts
index 0719b123c..fb30de3ab 100644
--- a/packages/jam/jam-host-calls/accumulate/forget.ts
+++ b/packages/jam/jam-host-calls/accumulate/forget.ts
@@ -1,9 +1,9 @@
 import type { ServiceId } from "@typeberry/block";
 import { Bytes } from "@typeberry/bytes";
 import { HASH_SIZE } from "@typeberry/hash";
-import type { HostCallHandler, IHostCallMemory, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { PvmExecution, traceRegisters, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { resultToString } from "@typeberry/utils";
 import type { PartialState } from "../externalities/partial-state.js";
 import { logger } from "../logger.js";
@@ -26,11 +26,7 @@ export class Forget implements HostCallHandler {
     private readonly partialState: PartialState,
   ) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<PvmExecution | undefined> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<PvmExecution | undefined> {
     // `o`
     const hashStart = regs.get(IN_OUT_REG);
     // `z`
diff --git a/packages/jam/jam-host-calls/accumulate/new.test.ts b/packages/jam/jam-host-calls/accumulate/new.test.ts
index e3dcee227..090d5c009 100644
--- a/packages/jam/jam-host-calls/accumulate/new.test.ts
+++ b/packages/jam/jam-host-calls/accumulate/new.test.ts
@@ -5,8 +5,8 @@ import { Bytes } from "@typeberry/bytes";
 import { HASH_SIZE } from "@typeberry/hash";
 import { tryAsU64, type U64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import { Registers } from "@typeberry/pvm-interpreter";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter } from "@typeberry/pvm-interpreter/gas.js";
 import { MemoryBuilder, tryAsMemoryIndex } from "@typeberry/pvm-interpreter/memory/index.js";
 import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
@@ -14,6 +14,7 @@ import { Compatibility, GpVersion, Result } from "@typeberry/utils";
 import { NewServiceError } from "../externalities/partial-state.js";
 import { PartialStateMock } from "../externalities/partial-state-mock.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { New } from "./new.js";
 
 const gas = gasCounter(tryAsGas(0));
@@ -36,7 +37,7 @@ function prepareRegsAndMemory(
   { skipCodeHash = false }: { skipCodeHash?: boolean } = {},
 ) {
   const memStart = 2 ** 16;
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(CODE_HASH_START_REG, tryAsU64(memStart));
   registers.set(CODE_LENGTH_REG, tryAsU64(codeLength));
   registers.set(GAS_REG, gas);
@@ -49,10 +50,10 @@ function prepareRegsAndMemory(
   if (!skipCodeHash) {
     builder.setReadablePages(tryAsMemoryIndex(memStart), tryAsMemoryIndex(memStart + PAGE_SIZE), codeHash.raw);
   }
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/accumulate/new.ts b/packages/jam/jam-host-calls/accumulate/new.ts
index a60d11918..f596db1d4 100644
--- a/packages/jam/jam-host-calls/accumulate/new.ts
+++ b/packages/jam/jam-host-calls/accumulate/new.ts
@@ -2,9 +2,9 @@ import { type ServiceId, tryAsServiceGas } from "@typeberry/block";
 import { Bytes } from "@typeberry/bytes";
 import { HASH_SIZE } from "@typeberry/hash";
 import { tryAsU64 } from "@typeberry/numbers";
-import type { HostCallHandler, IHostCallMemory, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { PvmExecution, traceRegisters, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { assertNever, Compatibility, GpVersion, resultToString } from "@typeberry/utils";
 import { NewServiceError, type PartialState } from "../externalities/partial-state.js";
 import { logger } from "../logger.js";
@@ -29,11 +29,7 @@ export class New implements HostCallHandler {
     private readonly partialState: PartialState,
   ) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<undefined | PvmExecution> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<undefined | PvmExecution> {
     // `o`
     const codeHashStart = regs.get(IN_OUT_REG);
     // `l`
diff --git a/packages/jam/jam-host-calls/accumulate/provide.test.ts b/packages/jam/jam-host-calls/accumulate/provide.test.ts
index b6c387e0d..5633904e4 100644
--- a/packages/jam/jam-host-calls/accumulate/provide.test.ts
+++ b/packages/jam/jam-host-calls/accumulate/provide.test.ts
@@ -4,19 +4,14 @@ import { type ServiceId, tryAsServiceId } from "@typeberry/block";
 import { BytesBlob } from "@typeberry/bytes";
 import { tryAsU64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import {
-  gasCounter,
-  MemoryBuilder,
-  Registers,
-  tryAsGas,
-  tryAsMemoryIndex,
-  tryAsSbrkIndex,
-} from "@typeberry/pvm-interpreter";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter, MemoryBuilder, tryAsMemoryIndex, tryAsSbrkIndex } from "@typeberry/pvm-interpreter";
 import { PAGE_SIZE } from "@typeberry/pvm-interpreter/memory/memory-consts.js";
 import { deepEqual, Result } from "@typeberry/utils";
 import { ProvidePreimageError } from "../externalities/partial-state.js";
 import { PartialStateMock } from "../externalities/partial-state-mock.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Provide } from "./provide.js";
 
 const gas = gasCounter(tryAsGas(0));
@@ -30,7 +25,7 @@ function prepareRegsAndMemory(
   { registerMemory = true }: { registerMemory?: boolean } = {},
 ) {
   const preimageStart = 2 ** 16;
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(RESULT_REG, tryAsU64(service));
   registers.set(PREIMAGE_START_REG, tryAsU64(preimageStart));
   registers.set(LENGTH_REG, tryAsU64(preimage.length));
@@ -44,10 +39,10 @@ function prepareRegsAndMemory(
     );
   }
 
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/accumulate/provide.ts b/packages/jam/jam-host-calls/accumulate/provide.ts
index 182f59ba5..0d7937161 100644
--- a/packages/jam/jam-host-calls/accumulate/provide.ts
+++ b/packages/jam/jam-host-calls/accumulate/provide.ts
@@ -2,13 +2,13 @@ import type { ServiceId } from "@typeberry/block";
 import { BytesBlob } from "@typeberry/bytes";
 import {
   type HostCallHandler,
-  type IHostCallMemory,
-  type IHostCallRegisters,
+  type HostCallMemory,
+  type HostCallRegisters,
   PvmExecution,
   traceRegisters,
   tryAsHostCallIndex,
 } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { assertNever, resultToString, safeAllocUint8Array } from "@typeberry/utils";
 import { type PartialState, ProvidePreimageError } from "../externalities/partial-state.js";
 import { logger } from "../logger.js";
@@ -32,7 +32,7 @@ export class Provide implements HostCallHandler {
     private readonly partialState: PartialState,
   ) {}
 
-  async execute(_gas: GasCounter, regs: IHostCallRegisters, memory: IHostCallMemory) {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory) {
     // `s`
     const serviceId = getServiceIdOrCurrent(IN_OUT_REG, regs, this.currentServiceId);
 
diff --git a/packages/jam/jam-host-calls/accumulate/query.test.ts b/packages/jam/jam-host-calls/accumulate/query.test.ts
index 153498010..041555823 100644
--- a/packages/jam/jam-host-calls/accumulate/query.test.ts
+++ b/packages/jam/jam-host-calls/accumulate/query.test.ts
@@ -5,18 +5,13 @@ import { Bytes, type BytesBlob } from "@typeberry/bytes";
 import { HASH_SIZE } from "@typeberry/hash";
 import { tryAsU32, tryAsU64, type U32 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import {
-  gasCounter,
-  MemoryBuilder,
-  Registers,
-  tryAsGas,
-  tryAsMemoryIndex,
-  tryAsSbrkIndex,
-} from "@typeberry/pvm-interpreter";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter, MemoryBuilder, tryAsMemoryIndex, tryAsSbrkIndex } from "@typeberry/pvm-interpreter";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
 import { type PreimageStatus, PreimageStatusKind } from "../externalities/partial-state.js";
 import { PartialStateMock } from "../externalities/partial-state-mock.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Query } from "./query.js";
 
 const gas = gasCounter(tryAsGas(0));
@@ -32,7 +27,7 @@ function prepareRegsAndMemory(
   data: BytesBlob,
   { registerMemory = true }: { registerMemory?: boolean } = {},
 ) {
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(HASH_START_REG, tryAsU64(hashStart));
   registers.set(LENGTH_REG, tryAsU64(length));
 
@@ -41,10 +36,10 @@ function prepareRegsAndMemory(
     builder.setReadablePages(tryAsMemoryIndex(hashStart), tryAsMemoryIndex(hashStart + PAGE_SIZE), data.raw);
   }
 
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/accumulate/query.ts b/packages/jam/jam-host-calls/accumulate/query.ts
index f56e49b36..1dea6476f 100644
--- a/packages/jam/jam-host-calls/accumulate/query.ts
+++ b/packages/jam/jam-host-calls/accumulate/query.ts
@@ -4,13 +4,13 @@ import { HASH_SIZE } from "@typeberry/hash";
 import { tryAsU64 } from "@typeberry/numbers";
 import {
   type HostCallHandler,
-  type IHostCallMemory,
-  type IHostCallRegisters,
+  type HostCallMemory,
+  type HostCallRegisters,
   PvmExecution,
   traceRegisters,
   tryAsHostCallIndex,
 } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { type PartialState, PreimageStatusKind } from "../externalities/partial-state.js";
 import { logger } from "../logger.js";
 import { HostCallResult } from "../results.js";
@@ -34,11 +34,7 @@ export class Query implements HostCallHandler {
     private readonly partialState: PartialState,
   ) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<PvmExecution | undefined> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<PvmExecution | undefined> {
     // `o`
     const hashStart = regs.get(IN_OUT_REG_1);
     // `z`
diff --git a/packages/jam/jam-host-calls/accumulate/solicit.test.ts b/packages/jam/jam-host-calls/accumulate/solicit.test.ts
index a88abbd42..e5a997829 100644
--- a/packages/jam/jam-host-calls/accumulate/solicit.test.ts
+++ b/packages/jam/jam-host-calls/accumulate/solicit.test.ts
@@ -5,8 +5,8 @@ import { Bytes } from "@typeberry/bytes";
 import { HASH_SIZE } from "@typeberry/hash";
 import { tryAsU64, type U64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import { Registers } from "@typeberry/pvm-interpreter";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter } from "@typeberry/pvm-interpreter/gas.js";
 import { MemoryBuilder, tryAsMemoryIndex } from "@typeberry/pvm-interpreter/memory/index.js";
 import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
@@ -14,6 +14,7 @@ import { Result } from "@typeberry/utils";
 import { RequestPreimageError } from "../externalities/partial-state.js";
 import { PartialStateMock } from "../externalities/partial-state-mock.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Solicit } from "./solicit.js";
 
 const gas = gasCounter(tryAsGas(0));
@@ -27,7 +28,7 @@ function prepareRegsAndMemory(
   { skipPreimageHash = false }: { skipPreimageHash?: boolean } = {},
 ) {
   const memStart = 2 ** 16;
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(HASH_START_REG, tryAsU64(memStart));
   registers.set(LENGTH_REG, preimageLength);
 
@@ -36,10 +37,10 @@ function prepareRegsAndMemory(
   if (!skipPreimageHash) {
     builder.setReadablePages(tryAsMemoryIndex(memStart), tryAsMemoryIndex(memStart + PAGE_SIZE), preimageHash.raw);
   }
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/accumulate/solicit.ts b/packages/jam/jam-host-calls/accumulate/solicit.ts
index 4edba67b4..752088550 100644
--- a/packages/jam/jam-host-calls/accumulate/solicit.ts
+++ b/packages/jam/jam-host-calls/accumulate/solicit.ts
@@ -1,9 +1,9 @@
 import type { ServiceId } from "@typeberry/block";
 import { Bytes } from "@typeberry/bytes";
 import { HASH_SIZE } from "@typeberry/hash";
-import type { HostCallHandler, IHostCallMemory, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { PvmExecution, traceRegisters, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { assertNever, resultToString } from "@typeberry/utils";
 import { type PartialState, RequestPreimageError } from "../externalities/partial-state.js";
 import { logger } from "../logger.js";
@@ -26,11 +26,7 @@ export class Solicit implements HostCallHandler {
     private readonly partialState: PartialState,
   ) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<PvmExecution | undefined> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<PvmExecution | undefined> {
     // `o`
     const hashStart = regs.get(IN_OUT_REG);
     // `z`
diff --git a/packages/jam/jam-host-calls/accumulate/transfer.test.ts b/packages/jam/jam-host-calls/accumulate/transfer.test.ts
index b3ffcb99c..78847d0b0 100644
--- a/packages/jam/jam-host-calls/accumulate/transfer.test.ts
+++ b/packages/jam/jam-host-calls/accumulate/transfer.test.ts
@@ -4,16 +4,17 @@ import { type ServiceId, tryAsServiceId } from "@typeberry/block";
 import { Bytes } from "@typeberry/bytes";
 import { tryAsU64, type U64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
+import { tryAsGas } from "@typeberry/pvm-interface";
 import { MemoryBuilder } from "@typeberry/pvm-interpreter";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
+import { gasCounter } from "@typeberry/pvm-interpreter/gas.js";
 import { tryAsMemoryIndex } from "@typeberry/pvm-interpreter/memory/index.js";
 import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
-import { Registers } from "@typeberry/pvm-interpreter/registers.js";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
 import { Compatibility, GpVersion, Result } from "@typeberry/utils";
 import { TRANSFER_MEMO_BYTES, TransferError } from "../externalities/partial-state.js";
 import { PartialStateMock } from "../externalities/partial-state-mock.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Transfer } from "./transfer.js";
 
 const RESULT_REG = 7;
@@ -30,7 +31,7 @@ function prepareRegsAndMemory(
   { skipMemo = false }: { skipMemo?: boolean } = {},
 ) {
   const memStart = 2 ** 16;
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(DESTINATION_REG, tryAsU64(destination));
   registers.set(AMOUNT_REG, amount);
   registers.set(ON_TRANSFER_GAS_REG, gas);
@@ -41,10 +42,10 @@ function prepareRegsAndMemory(
     builder.setReadablePages(tryAsMemoryIndex(memStart), tryAsMemoryIndex(memStart + PAGE_SIZE), memo.raw);
   }
 
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/accumulate/transfer.ts b/packages/jam/jam-host-calls/accumulate/transfer.ts
index 214c52f19..d28518d14 100644
--- a/packages/jam/jam-host-calls/accumulate/transfer.ts
+++ b/packages/jam/jam-host-calls/accumulate/transfer.ts
@@ -1,8 +1,8 @@
 import { type ServiceId, tryAsServiceGas } from "@typeberry/block";
 import { Bytes } from "@typeberry/bytes";
-import type { HostCallHandler, IHostCallMemory, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { PvmExecution, traceRegisters, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsGas, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type IGasCounter, tryAsGas, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { assertNever, Compatibility, GpVersion, resultToString } from "@typeberry/utils";
 import { type PartialState, TRANSFER_MEMO_BYTES, TransferError } from "../externalities/partial-state.js";
 import { logger } from "../logger.js";
@@ -40,7 +40,7 @@ export class Transfer implements HostCallHandler {
    */
   basicGasCost = Compatibility.isGreaterOrEqual(GpVersion.V0_7_2)
     ? tryAsSmallGas(10)
-    : (regs: IHostCallRegisters) => tryAsGas(10n + regs.get(TRANSFER_GAS_FEE_REG));
+    : (regs: HostCallRegisters) => tryAsGas(10n + regs.get(TRANSFER_GAS_FEE_REG));
 
   tracedRegisters = traceRegisters(IN_OUT_REG, AMOUNT_REG, TRANSFER_GAS_FEE_REG, MEMO_START_REG);
 
@@ -49,7 +49,7 @@ export class Transfer implements HostCallHandler {
     private readonly partialState: PartialState,
   ) {}
 
-  async execute(gas: GasCounter, regs: IHostCallRegisters, memory: IHostCallMemory): Promise<undefined | PvmExecution> {
+  async execute(gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<undefined | PvmExecution> {
     // `d`: destination
     const destination = getServiceId(regs.get(IN_OUT_REG));
     // `a`: amount
diff --git a/packages/jam/jam-host-calls/accumulate/upgrade.test.ts b/packages/jam/jam-host-calls/accumulate/upgrade.test.ts
index 68e4eec53..61a477a5e 100644
--- a/packages/jam/jam-host-calls/accumulate/upgrade.test.ts
+++ b/packages/jam/jam-host-calls/accumulate/upgrade.test.ts
@@ -5,13 +5,14 @@ import { Bytes } from "@typeberry/bytes";
 import { HASH_SIZE } from "@typeberry/hash";
 import { tryAsU64, type U64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import { Registers } from "@typeberry/pvm-interpreter";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter } from "@typeberry/pvm-interpreter/gas.js";
 import { MemoryBuilder, tryAsMemoryIndex } from "@typeberry/pvm-interpreter/memory/index.js";
 import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
 import { PartialStateMock } from "../externalities/partial-state-mock.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Upgrade } from "./upgrade.js";
 
 const gas = gasCounter(tryAsGas(0));
@@ -27,7 +28,7 @@ function prepareRegsAndMemory(
   { skipCodeHash = false }: { skipCodeHash?: boolean } = {},
 ) {
   const memStart = 2 ** 16;
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(CODE_HASH_START_REG, tryAsU64(memStart));
   registers.set(GAS_REG, gas);
   registers.set(BALANCE_REG, balance);
@@ -37,10 +38,10 @@ function prepareRegsAndMemory(
   if (!skipCodeHash) {
     builder.setReadablePages(tryAsMemoryIndex(memStart), tryAsMemoryIndex(memStart + PAGE_SIZE), codeHash.raw);
   }
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/accumulate/upgrade.ts b/packages/jam/jam-host-calls/accumulate/upgrade.ts
index c6539d070..3be6c7ff4 100644
--- a/packages/jam/jam-host-calls/accumulate/upgrade.ts
+++ b/packages/jam/jam-host-calls/accumulate/upgrade.ts
@@ -1,9 +1,9 @@
 import type { ServiceId } from "@typeberry/block";
 import { Bytes } from "@typeberry/bytes";
 import { HASH_SIZE } from "@typeberry/hash";
-import type { HostCallHandler, IHostCallMemory, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { PvmExecution, traceRegisters, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import type { PartialState } from "../externalities/partial-state.js";
 import { logger } from "../logger.js";
 import { HostCallResult } from "../results.js";
@@ -27,11 +27,7 @@ export class Upgrade implements HostCallHandler {
     private readonly partialState: PartialState,
   ) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<undefined | PvmExecution> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<undefined | PvmExecution> {
     // `o`
     const codeHashStart = regs.get(IN_OUT_REG);
     // `g`
diff --git a/packages/jam/jam-host-calls/accumulate/yield.test.ts b/packages/jam/jam-host-calls/accumulate/yield.test.ts
index b95cc7166..0903d1340 100644
--- a/packages/jam/jam-host-calls/accumulate/yield.test.ts
+++ b/packages/jam/jam-host-calls/accumulate/yield.test.ts
@@ -5,17 +5,12 @@ import { Bytes, type BytesBlob } from "@typeberry/bytes";
 import { HASH_SIZE } from "@typeberry/hash";
 import { tryAsU32, tryAsU64, type U32 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import {
-  gasCounter,
-  MemoryBuilder,
-  Registers,
-  tryAsGas,
-  tryAsMemoryIndex,
-  tryAsSbrkIndex,
-} from "@typeberry/pvm-interpreter";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter, MemoryBuilder, tryAsMemoryIndex, tryAsSbrkIndex } from "@typeberry/pvm-interpreter";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
 import { PartialStateMock } from "../externalities/partial-state-mock.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Yield } from "./yield.js";
 
 const gas = gasCounter(tryAsGas(0));
@@ -27,7 +22,7 @@ function prepareRegsAndMemory(
   data: BytesBlob,
   { registerMemory = true }: { registerMemory?: boolean } = {},
 ) {
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(HASH_START_REG, tryAsU64(hashStart));
 
   const builder = new MemoryBuilder();
@@ -35,10 +30,10 @@ function prepareRegsAndMemory(
     builder.setReadablePages(tryAsMemoryIndex(hashStart), tryAsMemoryIndex(hashStart + PAGE_SIZE), data.raw);
   }
 
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/accumulate/yield.ts b/packages/jam/jam-host-calls/accumulate/yield.ts
index 8cb63c764..0c6f8f2bf 100644
--- a/packages/jam/jam-host-calls/accumulate/yield.ts
+++ b/packages/jam/jam-host-calls/accumulate/yield.ts
@@ -3,13 +3,13 @@ import { Bytes } from "@typeberry/bytes";
 import { HASH_SIZE } from "@typeberry/hash";
 import {
   type HostCallHandler,
-  type IHostCallMemory,
-  type IHostCallRegisters,
+  type HostCallMemory,
+  type HostCallRegisters,
   PvmExecution,
   traceRegisters,
   tryAsHostCallIndex,
 } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import type { PartialState } from "../externalities/partial-state.js";
 import { logger } from "../logger.js";
 import { HostCallResult } from "../results.js";
@@ -31,11 +31,7 @@ export class Yield implements HostCallHandler {
     private readonly partialState: PartialState,
   ) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<PvmExecution | undefined> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<PvmExecution | undefined> {
     // `o`
     const hashStart = regs.get(IN_OUT_REG);
 
diff --git a/packages/jam/jam-host-calls/externalities/refine-externalities.test.ts b/packages/jam/jam-host-calls/externalities/refine-externalities.test.ts
index be4d797f7..58744303a 100644
--- a/packages/jam/jam-host-calls/externalities/refine-externalities.test.ts
+++ b/packages/jam/jam-host-calls/externalities/refine-externalities.test.ts
@@ -3,13 +3,12 @@ import type { BytesBlob } from "@typeberry/bytes";
 import { MultiMap } from "@typeberry/collections";
 import type { Blake2bHash } from "@typeberry/hash";
 import type { U64 } from "@typeberry/numbers";
-import type { IHostCallMemory } from "@typeberry/pvm-host-calls";
-import type { BigGas, Registers } from "@typeberry/pvm-interpreter";
+import type { HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
+import { type BigGas, Status } from "@typeberry/pvm-interface";
 import {
   ProgramDecoder,
   type ProgramDecoderError,
 } from "@typeberry/pvm-interpreter/program-decoder/program-decoder.js";
-import { Status } from "@typeberry/pvm-interpreter/status.js";
 import { type OK, Result } from "@typeberry/utils";
 import {
   type MachineId,
@@ -104,7 +103,7 @@ export class TestRefineExt implements RefineExternalities {
     destinationStart: U64,
     sourceStart: U64,
     length: U64,
-    destination: IHostCallMemory,
+    destination: HostCallMemory,
   ): Promise<Result<OK, PeekPokeError>> {
     const val = this.machinePeekData.get(machineIndex, destinationStart, sourceStart, length, destination);
     if (val === undefined) {
@@ -120,7 +119,7 @@ export class TestRefineExt implements RefineExternalities {
     sourceStart: U64,
     destinationStart: U64,
     length: U64,
-    source: IHostCallMemory,
+    source: HostCallMemory,
   ): Promise<Result<OK, PeekPokeError>> {
     const val = this.machinePokeData.get(machineIndex, sourceStart, destinationStart, length, source);
     if (val === undefined) {
@@ -134,7 +133,7 @@ export class TestRefineExt implements RefineExternalities {
   async machineInvoke(
     machineIndex: MachineId,
     gas: BigGas,
-    registers: Registers,
+    registers: HostCallRegisters,
   ): Promise<Result<MachineResult, NoMachineError>> {
     const machine = this.machineInvokeData.get(machineIndex);
     if (machine === undefined) {
diff --git a/packages/jam/jam-host-calls/externalities/refine-externalities.ts b/packages/jam/jam-host-calls/externalities/refine-externalities.ts
index 9997ed731..c2e62a78b 100644
--- a/packages/jam/jam-host-calls/externalities/refine-externalities.ts
+++ b/packages/jam/jam-host-calls/externalities/refine-externalities.ts
@@ -2,10 +2,9 @@ import type { Segment, SegmentIndex, ServiceId } from "@typeberry/block";
 import type { BytesBlob } from "@typeberry/bytes";
 import type { Blake2bHash } from "@typeberry/hash";
 import { tryAsU64, type U64 } from "@typeberry/numbers";
-import type { IHostCallMemory } from "@typeberry/pvm-host-calls";
-import type { BigGas, Registers } from "@typeberry/pvm-interpreter";
+import type { HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
+import { type BigGas, Status } from "@typeberry/pvm-interface";
 import type { ProgramDecoderError } from "@typeberry/pvm-interpreter/program-decoder/program-decoder.js";
-import { Status } from "@typeberry/pvm-interpreter/status.js";
 import { asOpaqueType, type OK, type Opaque, type Result } from "@typeberry/utils";
 
 /**
@@ -23,7 +22,7 @@ export type MachineId = Opaque<U64, "MachineId[u64]">;
 export const tryAsMachineId = (v: number | bigint): MachineId => asOpaqueType(tryAsU64(v));
 
 export class MachineInstance {
-  async run(gas: BigGas, registers: Registers): Promise<MachineResult> {
+  async run(gas: BigGas, registers: HostCallRegisters): Promise<MachineResult> {
     return {
       result: {
         status: Status.OK,
@@ -51,7 +50,7 @@ export type MachineStatus =
 export type MachineResult = {
   result: MachineStatus;
   gas: BigGas;
-  registers: Registers;
+  registers: HostCallRegisters;
 };
 
 /** Types of possbile operations to request by Pages host call. */
@@ -123,7 +122,7 @@ export interface RefineExternalities {
     destinationStart: U64,
     sourceStart: U64,
     length: U64,
-    destination: IHostCallMemory,
+    destination: HostCallMemory,
   ): Promise<Result<OK, PeekPokeError>>;
 
   /** Write a fragment of memory into `machineIndex` from given source memory. */
@@ -132,7 +131,7 @@ export interface RefineExternalities {
     sourceStart: U64,
     destinationStart: U64,
     length: U64,
-    source: IHostCallMemory,
+    source: HostCallMemory,
   ): Promise<Result<OK, PeekPokeError>>;
 
   /** Start an inner PVM instance with given entry point and starting code. */
@@ -142,7 +141,7 @@ export interface RefineExternalities {
   machineInvoke(
     machineIndex: MachineId,
     gas: BigGas,
-    registers: Registers,
+    registers: HostCallRegisters,
   ): Promise<Result<MachineResult, NoMachineError>>;
 
   /**
diff --git a/packages/jam/jam-host-calls/fetch.test.ts b/packages/jam/jam-host-calls/fetch.test.ts
index 3f27300bb..ee4b465fd 100644
--- a/packages/jam/jam-host-calls/fetch.test.ts
+++ b/packages/jam/jam-host-calls/fetch.test.ts
@@ -5,18 +5,13 @@ import { tryAsServiceId } from "@typeberry/block";
 import { BytesBlob } from "@typeberry/bytes";
 import { tryAsU64, type U64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import {
-  gasCounter,
-  MemoryBuilder,
-  Registers,
-  tryAsGas,
-  tryAsMemoryIndex,
-  tryAsSbrkIndex,
-} from "@typeberry/pvm-interpreter";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter, MemoryBuilder, tryAsMemoryIndex, tryAsSbrkIndex } from "@typeberry/pvm-interpreter";
 import { PAGE_SIZE } from "@typeberry/pvm-interpreter/memory/memory-consts.js";
 import { Compatibility, GpVersion } from "@typeberry/utils";
 import { Fetch, FetchKind, type IFetchExternalities } from "./fetch.js";
 import { HostCallResult } from "./results.js";
+import { emptyRegistersBuffer } from "./utils.js";
 
 describe("Fetch", () => {
   const IN_OUT_REG = 7;
@@ -32,7 +27,7 @@ describe("Fetch", () => {
 
     const badOffset = tryAsU64(0xfffff);
 
-    const registers = new HostCallRegisters(new Registers());
+    const registers = new HostCallRegisters(emptyRegistersBuffer());
     registers.set(IN_OUT_REG, badOffset);
     registers.set(8, tryAsU64(0));
     registers.set(9, tryAsU64(blob.length));
@@ -490,7 +485,7 @@ describe("Fetch", () => {
     const memOffset = tryAsU64(pageStart + 1234);
     const blobLength = tryAsU64(blob.length);
 
-    const registers = new HostCallRegisters(new Registers());
+    const registers = new HostCallRegisters(emptyRegistersBuffer());
     registers.set(IN_OUT_REG, memOffset);
     registers.set(8, tryAsU64(offset));
     registers.set(9, tryAsU64(length));
diff --git a/packages/jam/jam-host-calls/fetch.ts b/packages/jam/jam-host-calls/fetch.ts
index 0ffbb46c1..af2023031 100644
--- a/packages/jam/jam-host-calls/fetch.ts
+++ b/packages/jam/jam-host-calls/fetch.ts
@@ -1,9 +1,9 @@
 import type { ServiceId } from "@typeberry/block";
 import type { BytesBlob } from "@typeberry/bytes";
 import { minU64, tryAsU64, type U32, type U64 } from "@typeberry/numbers";
-import type { HostCallHandler, IHostCallMemory, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { PvmExecution, traceRegisters, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { Compatibility, GpVersion } from "@typeberry/utils";
 import { logger } from "./logger.js";
 import { HostCallResult } from "./results.js";
@@ -253,11 +253,7 @@ export class Fetch implements HostCallHandler {
     private readonly fetch: IFetchExternalities,
   ) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<undefined | PvmExecution> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<undefined | PvmExecution> {
     const fetchKindU64 = regs.get(10);
     const kind = clampU64ToU32(fetchKindU64);
     const value = this.getValue(kind, regs);
@@ -285,7 +281,7 @@ export class Fetch implements HostCallHandler {
     regs.set(IN_OUT_REG, value === null ? HostCallResult.NONE : valueLength);
   }
 
-  private getValue(kind: U32, regs: IHostCallRegisters): BytesBlob | null {
+  private getValue(kind: U32, regs: HostCallRegisters): BytesBlob | null {
     if (kind === FetchKind.Constants) {
       return this.fetch.constants();
     }
diff --git a/packages/jam/jam-host-calls/gas.test.ts b/packages/jam/jam-host-calls/gas.test.ts
index 4aa408be7..d48133eb4 100644
--- a/packages/jam/jam-host-calls/gas.test.ts
+++ b/packages/jam/jam-host-calls/gas.test.ts
@@ -2,9 +2,10 @@ import assert from "node:assert";
 import { describe, it } from "node:test";
 import { tryAsServiceId } from "@typeberry/block";
 import { HostCallRegisters } from "@typeberry/pvm-host-calls";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
-import { Registers } from "@typeberry/pvm-interpreter/registers.js";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter } from "@typeberry/pvm-interpreter";
 import { GasHostCall } from "./gas.js";
+import { emptyRegistersBuffer } from "./utils.js";
 
 const REGISTER = 7;
 
@@ -14,7 +15,7 @@ describe("HostCalls: Gas", () => {
     const gas = new GasHostCall(currentServiceId);
 
     const counter = gasCounter(tryAsGas(10_000));
-    const regs = new HostCallRegisters(new Registers());
+    const regs = new HostCallRegisters(emptyRegistersBuffer());
 
     assert.deepStrictEqual(regs.get(REGISTER), 0n);
 
@@ -30,7 +31,7 @@ describe("HostCalls: Gas", () => {
     const gas = new GasHostCall(currentServiceId);
 
     const counter = gasCounter(tryAsGas(2n ** 64n - 1n));
-    const regs = new HostCallRegisters(new Registers());
+    const regs = new HostCallRegisters(emptyRegistersBuffer());
 
     assert.deepStrictEqual(regs.get(REGISTER), 0n);
 
diff --git a/packages/jam/jam-host-calls/gas.ts b/packages/jam/jam-host-calls/gas.ts
index e9c8a9826..102401175 100644
--- a/packages/jam/jam-host-calls/gas.ts
+++ b/packages/jam/jam-host-calls/gas.ts
@@ -1,8 +1,8 @@
 import type { ServiceId } from "@typeberry/block";
 import { tryAsU64 } from "@typeberry/numbers";
-import type { HostCallHandler, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { type PvmExecution, traceRegisters, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { logger } from "./logger.js";
 
 /**
@@ -19,7 +19,7 @@ export class GasHostCall implements HostCallHandler {
 
   constructor(public readonly currentServiceId: ServiceId) {}
 
-  execute(gas: GasCounter, regs: IHostCallRegisters): Promise<undefined | PvmExecution> {
+  execute(gas: IGasCounter, regs: HostCallRegisters): Promise<undefined | PvmExecution> {
     const gasValue = gas.get();
     logger.trace`GAS <- ${gasValue}`;
     regs.set(7, tryAsU64(gasValue));
diff --git a/packages/jam/jam-host-calls/info.test.ts b/packages/jam/jam-host-calls/info.test.ts
index 58a05c3cb..2a70b7fec 100644
--- a/packages/jam/jam-host-calls/info.test.ts
+++ b/packages/jam/jam-host-calls/info.test.ts
@@ -5,8 +5,8 @@ import { Bytes, BytesBlob } from "@typeberry/bytes";
 import { Decoder, tryAsExactBytes } from "@typeberry/codec";
 import { tryAsU32, tryAsU64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import { Registers } from "@typeberry/pvm-interpreter";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter } from "@typeberry/pvm-interpreter";
 import { MemoryBuilder, tryAsMemoryIndex } from "@typeberry/pvm-interpreter/memory/index.js";
 import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
@@ -14,6 +14,7 @@ import { ServiceAccountInfo } from "@typeberry/state";
 import { TestAccounts } from "./externalities/test-accounts.js";
 import { codecServiceAccountInfoWithThresholdBalance, Info, LEN_REG } from "./info.js";
 import { HostCallResult } from "./results.js";
+import { emptyRegistersBuffer } from "./utils.js";
 
 const SERVICE_ID_REG = 7;
 const RESULT_REG = SERVICE_ID_REG;
@@ -26,23 +27,23 @@ const serviceAccountInfoSize = tryAsExactBytes(codecServiceAccountInfoWithThresh
 function prepareRegsAndMemory(serviceId: ServiceId, accountInfoLength = serviceAccountInfoSize) {
   const pageStart = 2 ** 16;
   const memStart = pageStart + PAGE_SIZE - accountInfoLength - 1;
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(SERVICE_ID_REG, tryAsU64(serviceId));
   registers.set(DEST_START_REG, tryAsU64(memStart));
   registers.set(LEN_REG, tryAsU64(serviceAccountInfoSize));
 
   const builder = new MemoryBuilder();
   builder.setWriteablePages(tryAsMemoryIndex(pageStart), tryAsMemoryIndex(pageStart + PAGE_SIZE));
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
 
   const readRaw = () => {
     const result = new Uint8Array(Number(registers.get(LEN_REG)));
-    assert.strictEqual(memory.loadInto(result, tryAsMemoryIndex(memStart)).isOk, true);
+    assert.strictEqual(memory.loadInto(result, tryAsU64(memStart)).isOk, true);
     return BytesBlob.blobFrom(result);
   };
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
     readRaw,
     readInfo: () => {
       const data = readRaw();
diff --git a/packages/jam/jam-host-calls/info.ts b/packages/jam/jam-host-calls/info.ts
index e28243ae8..f4745b27d 100644
--- a/packages/jam/jam-host-calls/info.ts
+++ b/packages/jam/jam-host-calls/info.ts
@@ -3,9 +3,9 @@ import { BytesBlob } from "@typeberry/bytes";
 import { codec, Encoder } from "@typeberry/codec";
 import { HASH_SIZE } from "@typeberry/hash";
 import { minU64, tryAsU64 } from "@typeberry/numbers";
-import type { HostCallHandler, IHostCallMemory, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { PvmExecution, traceRegisters, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { ServiceAccountInfo } from "@typeberry/state";
 import { Compatibility, GpVersion, TestSuite } from "@typeberry/utils";
 import { logger } from "./logger.js";
@@ -53,11 +53,7 @@ export class Info implements HostCallHandler {
     private readonly account: AccountsInfo,
   ) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<undefined | PvmExecution> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<undefined | PvmExecution> {
     // t
     const serviceId = getServiceIdOrCurrent(IN_OUT_REG, regs, this.currentServiceId);
     // o
diff --git a/packages/jam/jam-host-calls/log.ts b/packages/jam/jam-host-calls/log.ts
index 231772c6c..1f9e86ddb 100644
--- a/packages/jam/jam-host-calls/log.ts
+++ b/packages/jam/jam-host-calls/log.ts
@@ -1,7 +1,7 @@
 import type { ServiceId } from "@typeberry/block";
-import type { HostCallHandler, IHostCallMemory, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { type PvmExecution, traceRegisters, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { safeAllocUint8Array } from "@typeberry/utils";
 import { logger } from "./logger.js";
 import { clampU64ToU32 } from "./utils.js";
@@ -21,7 +21,7 @@ export class LogHostCall implements HostCallHandler {
 
   constructor(public readonly currentServiceId: ServiceId) {}
 
-  execute(_gas: GasCounter, regs: IHostCallRegisters, memory: IHostCallMemory): Promise<undefined | PvmExecution> {
+  execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<undefined | PvmExecution> {
     const lvl = regs.get(7);
     const targetStart = regs.get(8);
     const targetLength = regs.get(9);
diff --git a/packages/jam/jam-host-calls/lookup.test.ts b/packages/jam/jam-host-calls/lookup.test.ts
index bd4825425..9fc17206b 100644
--- a/packages/jam/jam-host-calls/lookup.test.ts
+++ b/packages/jam/jam-host-calls/lookup.test.ts
@@ -5,14 +5,15 @@ import { Bytes, BytesBlob } from "@typeberry/bytes";
 import { Blake2b, type Blake2bHash } from "@typeberry/hash";
 import { tryAsU64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import { Registers } from "@typeberry/pvm-interpreter";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter } from "@typeberry/pvm-interpreter";
 import { MemoryBuilder, tryAsMemoryIndex } from "@typeberry/pvm-interpreter/memory/index.js";
 import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
 import { TestAccounts } from "./externalities/test-accounts.js";
 import { Lookup } from "./lookup.js";
 import { HostCallResult } from "./results.js";
+import { emptyRegistersBuffer } from "./utils.js";
 
 let blake2b: Blake2b;
 let HASH: Blake2bHash;
@@ -45,7 +46,7 @@ function prepareRegsAndMemory(
     preimageLength = 0,
   }: { skipKey?: boolean; skipValue?: boolean; preimageOffset?: number; preimageLength?: number } = {},
 ) {
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(SERVICE_ID_REG, tryAsU64(serviceId));
   registers.set(HASH_ADDRESS_REG, tryAsU64(PREIMAGE_HASH_ADDRESS));
   registers.set(DEST_ADDRESS_REG, tryAsU64(DESTINATION_MEM_ADDRESS));
@@ -66,10 +67,10 @@ function prepareRegsAndMemory(
       tryAsMemoryIndex(DESTINATION_MEM_ADDRESS + PAGE_SIZE),
     );
   }
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/lookup.ts b/packages/jam/jam-host-calls/lookup.ts
index ca56c8486..2c385173c 100644
--- a/packages/jam/jam-host-calls/lookup.ts
+++ b/packages/jam/jam-host-calls/lookup.ts
@@ -2,9 +2,9 @@ import type { ServiceId } from "@typeberry/block";
 import { Bytes, type BytesBlob } from "@typeberry/bytes";
 import { type Blake2bHash, HASH_SIZE } from "@typeberry/hash";
 import { minU64, tryAsU64 } from "@typeberry/numbers";
-import type { HostCallHandler, IHostCallMemory, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { PvmExecution, traceRegisters, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { safeAllocUint8Array } from "@typeberry/utils";
 import { logger } from "./logger.js";
 import { HostCallResult } from "./results.js";
@@ -34,11 +34,7 @@ export class Lookup implements HostCallHandler {
     private readonly account: AccountsLookup,
   ) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<undefined | PvmExecution> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<undefined | PvmExecution> {
     // a
     const serviceId = getServiceIdOrCurrent(IN_OUT_REG, regs, this.currentServiceId);
 
diff --git a/packages/jam/jam-host-calls/missing.ts b/packages/jam/jam-host-calls/missing.ts
index 58862f6ec..8f9177b5d 100644
--- a/packages/jam/jam-host-calls/missing.ts
+++ b/packages/jam/jam-host-calls/missing.ts
@@ -1,12 +1,12 @@
 import {
   type HostCallHandler,
-  type IHostCallMemory,
-  type IHostCallRegisters,
+  type HostCallMemory,
+  type HostCallRegisters,
   type PvmExecution,
   traceRegisters,
   tryAsHostCallIndex,
 } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { HostCallResult } from "./results.js";
 import { CURRENT_SERVICE_ID } from "./utils.js";
 
@@ -16,7 +16,7 @@ export class Missing implements HostCallHandler {
   currentServiceId = CURRENT_SERVICE_ID;
   tracedRegisters = traceRegisters(7);
 
-  execute(_gas: GasCounter, regs: IHostCallRegisters, _memory: IHostCallMemory): Promise<PvmExecution | undefined> {
+  execute(_gas: IGasCounter, regs: HostCallRegisters, _memory: HostCallMemory): Promise<PvmExecution | undefined> {
     regs.set(7, HostCallResult.WHAT);
     return Promise.resolve(undefined);
   }
diff --git a/packages/jam/jam-host-calls/package.json b/packages/jam/jam-host-calls/package.json
index a369cbfcb..1099ec986 100644
--- a/packages/jam/jam-host-calls/package.json
+++ b/packages/jam/jam-host-calls/package.json
@@ -14,6 +14,7 @@
     "@typeberry/logger": "*",
     "@typeberry/numbers": "*",
     "@typeberry/pvm-host-calls": "*",
+    "@typeberry/pvm-interface": "*",
     "@typeberry/pvm-interpreter": "*",
     "@typeberry/state": "*",
     "@typeberry/utils": "*"
diff --git a/packages/jam/jam-host-calls/read.test.ts b/packages/jam/jam-host-calls/read.test.ts
index 059a5ddab..8ba697b48 100644
--- a/packages/jam/jam-host-calls/read.test.ts
+++ b/packages/jam/jam-host-calls/read.test.ts
@@ -4,8 +4,8 @@ import { type ServiceId, tryAsServiceId } from "@typeberry/block";
 import { BytesBlob } from "@typeberry/bytes";
 import { tryAsU64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import { Registers } from "@typeberry/pvm-interpreter";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter } from "@typeberry/pvm-interpreter";
 import { MemoryBuilder, tryAsMemoryIndex } from "@typeberry/pvm-interpreter/memory/index.js";
 import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
@@ -13,6 +13,7 @@ import { asOpaqueType, OK, Result } from "@typeberry/utils";
 import { TestAccounts } from "./externalities/test-accounts.js";
 import { Read } from "./read.js";
 import { HostCallResult } from "./results.js";
+import { emptyRegistersBuffer } from "./utils.js";
 
 const gas = gasCounter(tryAsGas(0));
 const SERVICE_ID_REG = 7;
@@ -42,7 +43,7 @@ function prepareRegsAndMemory(
 ) {
   const keyAddress = 2 ** 20;
   const memStart = 2 ** 16;
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   if (serviceId !== undefined) {
     registers.set(SERVICE_ID_REG, tryAsU64(serviceId));
   } else {
@@ -61,13 +62,13 @@ function prepareRegsAndMemory(
   if (!skipValue) {
     builder.setWriteablePages(tryAsMemoryIndex(memStart), tryAsMemoryIndex(memStart + PAGE_SIZE));
   }
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
     readResult: () => {
       const result = new Uint8Array(valueLength - valueOffset);
-      assert.deepStrictEqual(memory.loadInto(result, tryAsMemoryIndex(memStart)), Result.ok(OK));
+      assert.deepStrictEqual(memory.loadInto(result, tryAsU64(memStart)), Result.ok(OK));
       return BytesBlob.blobFrom(result);
     },
   };
diff --git a/packages/jam/jam-host-calls/read.ts b/packages/jam/jam-host-calls/read.ts
index 98b4ca1f7..8bf624da0 100644
--- a/packages/jam/jam-host-calls/read.ts
+++ b/packages/jam/jam-host-calls/read.ts
@@ -1,9 +1,9 @@
 import type { ServiceId } from "@typeberry/block";
 import { BytesBlob } from "@typeberry/bytes";
 import { minU64, tryAsU64 } from "@typeberry/numbers";
-import type { HostCallHandler, IHostCallMemory, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { PvmExecution, traceRegisters, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { safeAllocUint8Array } from "@typeberry/utils";
 import { logger } from "./logger.js";
 import { HostCallResult } from "./results.js";
@@ -32,11 +32,7 @@ export class Read implements HostCallHandler {
     private readonly account: AccountsRead,
   ) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<undefined | PvmExecution> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<undefined | PvmExecution> {
     // a
     const serviceId = getServiceIdOrCurrent(IN_OUT_REG, regs, this.currentServiceId);
 
diff --git a/packages/jam/jam-host-calls/refine/export.test.ts b/packages/jam/jam-host-calls/refine/export.test.ts
index f960f8bb3..a2325d089 100644
--- a/packages/jam/jam-host-calls/refine/export.test.ts
+++ b/packages/jam/jam-host-calls/refine/export.test.ts
@@ -4,8 +4,8 @@ import { SEGMENT_BYTES, type Segment, tryAsSegmentIndex, tryAsServiceId } from "
 import { Bytes } from "@typeberry/bytes";
 import { tryAsU64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import { Registers } from "@typeberry/pvm-interpreter";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter } from "@typeberry/pvm-interpreter/gas.js";
 import { MemoryBuilder, tryAsMemoryIndex } from "@typeberry/pvm-interpreter/memory/index.js";
 import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
@@ -13,6 +13,7 @@ import { Result } from "@typeberry/utils";
 import { SegmentExportError } from "../externalities/refine-externalities.js";
 import { TestRefineExt } from "../externalities/refine-externalities.test.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Export } from "./export.js";
 
 const gas = gasCounter(tryAsGas(0));
@@ -26,7 +27,7 @@ function prepareRegsAndMemory(
   { skipSegment = false }: { skipSegment?: boolean } = {},
 ) {
   const memStart = 2 ** 23;
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(SEGMENT_START_REG, tryAsU64(memStart));
   registers.set(SEGMENT_LENGTH_REG, tryAsU64(segmentLength));
 
@@ -34,10 +35,10 @@ function prepareRegsAndMemory(
   if (!skipSegment) {
     builder.setReadablePages(tryAsMemoryIndex(memStart), tryAsMemoryIndex(memStart + 2 * PAGE_SIZE), segment.raw);
   }
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/refine/export.ts b/packages/jam/jam-host-calls/refine/export.ts
index ce2a01454..669db94d3 100644
--- a/packages/jam/jam-host-calls/refine/export.ts
+++ b/packages/jam/jam-host-calls/refine/export.ts
@@ -3,13 +3,13 @@ import { Bytes } from "@typeberry/bytes";
 import { minU64, tryAsU64 } from "@typeberry/numbers";
 import {
   type HostCallHandler,
-  type IHostCallMemory,
-  type IHostCallRegisters,
+  type HostCallMemory,
+  type HostCallRegisters,
   PvmExecution,
   traceRegisters,
   tryAsHostCallIndex,
 } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { resultToString } from "@typeberry/utils";
 import type { RefineExternalities } from "../externalities/refine-externalities.js";
 import { logger } from "../logger.js";
@@ -31,11 +31,7 @@ export class Export implements HostCallHandler {
 
   constructor(private readonly refine: RefineExternalities) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<PvmExecution | undefined> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<PvmExecution | undefined> {
     // `p`: segment start address
     const segmentStart = regs.get(IN_OUT_REG);
     // `z`: segment bounded length
diff --git a/packages/jam/jam-host-calls/refine/expunge.test.ts b/packages/jam/jam-host-calls/refine/expunge.test.ts
index 6828b1d2d..a40fe3e3a 100644
--- a/packages/jam/jam-host-calls/refine/expunge.test.ts
+++ b/packages/jam/jam-host-calls/refine/expunge.test.ts
@@ -2,7 +2,8 @@ import assert from "node:assert";
 import { describe, it } from "node:test";
 import { tryAsServiceId } from "@typeberry/block";
 import { HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
-import { gasCounter, MemoryBuilder, Registers, tryAsGas } from "@typeberry/pvm-interpreter";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter, MemoryBuilder } from "@typeberry/pvm-interpreter";
 import { tryAsMemoryIndex, tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
 import { Result } from "@typeberry/utils";
 import {
@@ -14,21 +15,22 @@ import {
 } from "../externalities/refine-externalities.js";
 import { TestRefineExt } from "../externalities/refine-externalities.test.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Expunge } from "./expunge.js";
 
 const gas = gasCounter(tryAsGas(0));
 const RESULT_REG = 7;
 
 function prepareRegsAndMemory(machineId: MachineId) {
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(7, machineId);
 
   const builder = new MemoryBuilder();
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
 
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/refine/expunge.ts b/packages/jam/jam-host-calls/refine/expunge.ts
index be3259c0a..592b532f7 100644
--- a/packages/jam/jam-host-calls/refine/expunge.ts
+++ b/packages/jam/jam-host-calls/refine/expunge.ts
@@ -1,11 +1,11 @@
 import {
   type HostCallHandler,
-  type IHostCallRegisters,
+  type HostCallRegisters,
   type PvmExecution,
   traceRegisters,
   tryAsHostCallIndex,
 } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { resultToString } from "@typeberry/utils";
 import { type RefineExternalities, tryAsMachineId } from "../externalities/refine-externalities.js";
 import { logger } from "../logger.js";
@@ -27,7 +27,7 @@ export class Expunge implements HostCallHandler {
 
   constructor(private readonly refine: RefineExternalities) {}
 
-  async execute(_gas: GasCounter, regs: IHostCallRegisters): Promise<PvmExecution | undefined> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters): Promise<PvmExecution | undefined> {
     // `n`: machine index
     const machineIndex = tryAsMachineId(regs.get(IN_OUT_REG));
 
diff --git a/packages/jam/jam-host-calls/refine/historical-lookup.test.ts b/packages/jam/jam-host-calls/refine/historical-lookup.test.ts
index 168381502..09339da34 100644
--- a/packages/jam/jam-host-calls/refine/historical-lookup.test.ts
+++ b/packages/jam/jam-host-calls/refine/historical-lookup.test.ts
@@ -5,13 +5,14 @@ import { Bytes, BytesBlob } from "@typeberry/bytes";
 import type { Blake2bHash } from "@typeberry/hash";
 import { tryAsU64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import { Registers } from "@typeberry/pvm-interpreter";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter } from "@typeberry/pvm-interpreter/gas.js";
 import { MemoryBuilder, tryAsMemoryIndex } from "@typeberry/pvm-interpreter/memory/index.js";
 import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
 import { TestRefineExt } from "../externalities/refine-externalities.test.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { HistoricalLookup } from "./historical-lookup.js";
 
 const gas = gasCounter(tryAsGas(0));
@@ -31,7 +32,7 @@ function prepareRegsAndMemory(
 ) {
   const hashAddress = 2 ** 16;
   const memStart = 2 ** 20;
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(SERVICE_ID_REG, tryAsU64(serviceId));
   registers.set(HASH_START_REG, tryAsU64(hashAddress));
   registers.set(DEST_START_REG, tryAsU64(memStart));
@@ -45,13 +46,13 @@ function prepareRegsAndMemory(
   if (writableMemory) {
     builder.setWriteablePages(tryAsMemoryIndex(memStart), tryAsMemoryIndex(memStart + PAGE_SIZE));
   }
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
     readResult: () => {
       const result = new Uint8Array(destinationLength);
-      assert.strictEqual(memory.loadInto(result, tryAsMemoryIndex(memStart)).isOk, true);
+      assert.strictEqual(memory.loadInto(result, tryAsU64(memStart)).isOk, true);
       return BytesBlob.blobFrom(result);
     },
   };
diff --git a/packages/jam/jam-host-calls/refine/historical-lookup.ts b/packages/jam/jam-host-calls/refine/historical-lookup.ts
index 2d18ada54..165b97c33 100644
--- a/packages/jam/jam-host-calls/refine/historical-lookup.ts
+++ b/packages/jam/jam-host-calls/refine/historical-lookup.ts
@@ -3,13 +3,13 @@ import { HASH_SIZE } from "@typeberry/hash";
 import { minU64, tryAsU64 } from "@typeberry/numbers";
 import {
   type HostCallHandler,
-  type IHostCallMemory,
-  type IHostCallRegisters,
+  type HostCallMemory,
+  type HostCallRegisters,
   PvmExecution,
   traceRegisters,
   tryAsHostCallIndex,
 } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import type { RefineExternalities } from "../externalities/refine-externalities.js";
 import { logger } from "../logger.js";
 import { HostCallResult } from "../results.js";
@@ -30,11 +30,7 @@ export class HistoricalLookup implements HostCallHandler {
 
   constructor(private readonly refine: RefineExternalities) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<PvmExecution | undefined> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<PvmExecution | undefined> {
     // a
     const serviceId = getServiceIdOrCurrent(IN_OUT_REG, regs, this.currentServiceId);
     // h
diff --git a/packages/jam/jam-host-calls/refine/invoke.test.ts b/packages/jam/jam-host-calls/refine/invoke.test.ts
index d87ada5a6..8b600387d 100644
--- a/packages/jam/jam-host-calls/refine/invoke.test.ts
+++ b/packages/jam/jam-host-calls/refine/invoke.test.ts
@@ -4,10 +4,10 @@ import { tryAsServiceId } from "@typeberry/block";
 import { Bytes, type BytesBlob } from "@typeberry/bytes";
 import { tryAsU64, type U64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import { gasCounter, MemoryBuilder, Registers, tryAsGas, tryAsMemoryIndex } from "@typeberry/pvm-interpreter";
+import { Status, tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter, MemoryBuilder } from "@typeberry/pvm-interpreter";
 import { RESERVED_NUMBER_OF_PAGES } from "@typeberry/pvm-interpreter/memory/memory-consts.js";
-import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
-import { Status } from "@typeberry/pvm-interpreter/status.js";
+import { tryAsMemoryIndex, tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
 import {
   type MachineId,
@@ -17,6 +17,7 @@ import {
 } from "../externalities/refine-externalities.js";
 import { TestRefineExt } from "../externalities/refine-externalities.test.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Invoke } from "./invoke.js";
 
 const gas = gasCounter(tryAsGas(0));
@@ -33,15 +34,15 @@ function prepareRegsAndMemory(
   data: BytesBlob,
   { registerMemory = true }: { registerMemory?: boolean } = {},
 ) {
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(MACHINE_INDEX_REG, machineIndex);
   registers.set(DEST_REG, tryAsU64(destinationStart));
 
-  const memory = prepareMemory(data, destinationStart, PAGE_SIZE, { registerMemory });
+  const memory = new HostCallMemory(prepareMemory(data, destinationStart, PAGE_SIZE, { registerMemory }));
 
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/refine/invoke.ts b/packages/jam/jam-host-calls/refine/invoke.ts
index db44612df..a7be054cc 100644
--- a/packages/jam/jam-host-calls/refine/invoke.ts
+++ b/packages/jam/jam-host-calls/refine/invoke.ts
@@ -3,15 +3,20 @@ import { codec, Decoder, Encoder, tryAsExactBytes } from "@typeberry/codec";
 import { tryAsU64 } from "@typeberry/numbers";
 import {
   type HostCallHandler,
-  type IHostCallMemory,
-  type IHostCallRegisters,
+  type HostCallMemory,
+  HostCallRegisters,
   PvmExecution,
   traceRegisters,
   tryAsHostCallIndex,
 } from "@typeberry/pvm-host-calls";
-import { type GasCounter, Registers, tryAsBigGas, tryAsSmallGas } from "@typeberry/pvm-interpreter";
-import { NO_OF_REGISTERS } from "@typeberry/pvm-interpreter/registers.js";
-import { Status } from "@typeberry/pvm-interpreter/status.js";
+import {
+  type IGasCounter,
+  NO_OF_REGISTERS,
+  REGISTER_BYTE_SIZE,
+  Status,
+  tryAsBigGas,
+  tryAsSmallGas,
+} from "@typeberry/pvm-interface";
 import { check, resultToString } from "@typeberry/utils";
 import { type RefineExternalities, tryAsMachineId } from "../externalities/refine-externalities.js";
 import { logger } from "../logger.js";
@@ -22,7 +27,7 @@ const IN_OUT_REG_1 = 7;
 const IN_OUT_REG_2 = 8;
 const gasAndRegistersCodec = codec.object({
   gas: codec.i64,
-  registers: codec.bytes(NO_OF_REGISTERS * 8),
+  registers: codec.bytes(NO_OF_REGISTERS * REGISTER_BYTE_SIZE),
 });
 const GAS_REGISTERS_SIZE = tryAsExactBytes(gasAndRegistersCodec.sizeHint);
 
@@ -39,11 +44,7 @@ export class Invoke implements HostCallHandler {
 
   constructor(private readonly refine: RefineExternalities) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<PvmExecution | undefined> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<PvmExecution | undefined> {
     // `n`: machine index
     const machineIndex = tryAsMachineId(regs.get(IN_OUT_REG_1));
     // `o`: destination memory start (local)
@@ -70,7 +71,7 @@ export class Invoke implements HostCallHandler {
     // `g`
     const gasCost = tryAsBigGas(gasRegisters.gas);
     // `w`
-    const registers = Registers.fromBytes(gasRegisters.registers.raw);
+    const registers = new HostCallRegisters(gasRegisters.registers.raw);
 
     // try run the machine
     const state = await this.refine.machineInvoke(machineIndex, gasCost, registers);
@@ -86,7 +87,7 @@ export class Invoke implements HostCallHandler {
     // save the result to the destination memory
     const resultData = Encoder.encodeObject(gasAndRegistersCodec, {
       gas: machineState.gas,
-      registers: Bytes.fromBlob(machineState.registers.getAllBytesAsLittleEndian(), NO_OF_REGISTERS * 8),
+      registers: Bytes.fromBlob(machineState.registers.getEncoded(), NO_OF_REGISTERS * REGISTER_BYTE_SIZE),
     });
 
     // this fault does not need to be handled, because we've ensured it's
diff --git a/packages/jam/jam-host-calls/refine/machine.test.ts b/packages/jam/jam-host-calls/refine/machine.test.ts
index 2f81e2b23..ac342f23e 100644
--- a/packages/jam/jam-host-calls/refine/machine.test.ts
+++ b/packages/jam/jam-host-calls/refine/machine.test.ts
@@ -4,12 +4,14 @@ import { tryAsServiceId } from "@typeberry/block";
 import { BytesBlob } from "@typeberry/bytes";
 import { tryAsU64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import { gasCounter, MemoryBuilder, Registers, tryAsGas, tryAsMemoryIndex } from "@typeberry/pvm-interpreter";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter, MemoryBuilder, tryAsMemoryIndex } from "@typeberry/pvm-interpreter";
 import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
 import { type ProgramCounter, tryAsMachineId, tryAsProgramCounter } from "../externalities/refine-externalities.js";
 import { TestRefineExt } from "../externalities/refine-externalities.test.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Machine } from "./machine.js";
 
 const gas = gasCounter(tryAsGas(0));
@@ -20,7 +22,7 @@ const PC_REG = 9;
 
 function prepareRegsAndMemory(code: BytesBlob, pc: ProgramCounter, { skipCode = false }: { skipCode?: boolean } = {}) {
   const memStart = 2 ** 20;
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(CODE_START_REG, tryAsU64(memStart));
   registers.set(CODE_LEN_REG, tryAsU64(code.length));
   registers.set(PC_REG, pc);
@@ -29,10 +31,10 @@ function prepareRegsAndMemory(code: BytesBlob, pc: ProgramCounter, { skipCode =
   if (!skipCode) {
     builder.setReadablePages(tryAsMemoryIndex(memStart), tryAsMemoryIndex(memStart + PAGE_SIZE), code.raw);
   }
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/refine/machine.ts b/packages/jam/jam-host-calls/refine/machine.ts
index 6d3740274..b2f9b3d67 100644
--- a/packages/jam/jam-host-calls/refine/machine.ts
+++ b/packages/jam/jam-host-calls/refine/machine.ts
@@ -1,13 +1,13 @@
 import { BytesBlob } from "@typeberry/bytes";
 import {
   type HostCallHandler,
-  type IHostCallMemory,
-  type IHostCallRegisters,
+  type HostCallMemory,
+  type HostCallRegisters,
   PvmExecution,
   traceRegisters,
   tryAsHostCallIndex,
 } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { resultToString, safeAllocUint8Array } from "@typeberry/utils";
 import { type RefineExternalities, tryAsProgramCounter } from "../externalities/refine-externalities.js";
 import { logger } from "../logger.js";
@@ -29,11 +29,7 @@ export class Machine implements HostCallHandler {
 
   constructor(private readonly refine: RefineExternalities) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<PvmExecution | undefined> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<PvmExecution | undefined> {
     // `p_o`: memory index where there program code starts
     const codeStart = regs.get(IN_OUT_REG);
     // `p_z`: length of the program code
diff --git a/packages/jam/jam-host-calls/refine/pages.test.ts b/packages/jam/jam-host-calls/refine/pages.test.ts
index df5908a8c..c0263bd94 100644
--- a/packages/jam/jam-host-calls/refine/pages.test.ts
+++ b/packages/jam/jam-host-calls/refine/pages.test.ts
@@ -2,15 +2,9 @@ import assert from "node:assert";
 import { describe, it } from "node:test";
 import { tryAsServiceId } from "@typeberry/block";
 import { tryAsU64, type U64 } from "@typeberry/numbers";
-import { HostCallRegisters } from "@typeberry/pvm-host-calls";
-import {
-  gasCounter,
-  MemoryBuilder,
-  Registers,
-  tryAsGas,
-  tryAsMemoryIndex,
-  tryAsSbrkIndex,
-} from "@typeberry/pvm-interpreter";
+import { HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter, MemoryBuilder, tryAsMemoryIndex, tryAsSbrkIndex } from "@typeberry/pvm-interpreter";
 import { OK, Result } from "@typeberry/utils";
 import {
   type MachineId,
@@ -20,20 +14,21 @@ import {
 } from "../externalities/refine-externalities.js";
 import { TestRefineExt } from "../externalities/refine-externalities.test.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Pages } from "./pages.js";
 
 const gas = gasCounter(tryAsGas(0));
 const RESULT_REG = 7;
 
 function prepareRegsAndMemory(machineId: MachineId, pageStart: U64, pageCount: U64, requestType: U64) {
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(7, machineId);
   registers.set(8, pageStart);
   registers.set(9, pageCount);
   registers.set(10, requestType);
 
   const builder = new MemoryBuilder();
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
 
   return {
     registers,
diff --git a/packages/jam/jam-host-calls/refine/pages.ts b/packages/jam/jam-host-calls/refine/pages.ts
index 82d70e7ff..6163741bb 100644
--- a/packages/jam/jam-host-calls/refine/pages.ts
+++ b/packages/jam/jam-host-calls/refine/pages.ts
@@ -1,11 +1,11 @@
 import {
   type HostCallHandler,
-  type IHostCallRegisters,
+  type HostCallRegisters,
   type PvmExecution,
   traceRegisters,
   tryAsHostCallIndex,
 } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { assertNever, resultToString } from "@typeberry/utils";
 import {
   PagesError,
@@ -33,7 +33,7 @@ export class Pages implements HostCallHandler {
 
   constructor(private readonly refine: RefineExternalities) {}
 
-  async execute(_gas: GasCounter, regs: IHostCallRegisters): Promise<PvmExecution | undefined> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters): Promise<PvmExecution | undefined> {
     // `n`: machine index
     const machineIndex = tryAsMachineId(regs.get(IN_OUT_REG));
     // `p`: start page
diff --git a/packages/jam/jam-host-calls/refine/peek.test.ts b/packages/jam/jam-host-calls/refine/peek.test.ts
index 093b649b3..0e014d585 100644
--- a/packages/jam/jam-host-calls/refine/peek.test.ts
+++ b/packages/jam/jam-host-calls/refine/peek.test.ts
@@ -3,36 +3,31 @@ import { describe, it } from "node:test";
 import { tryAsServiceId } from "@typeberry/block";
 import { tryAsU64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import {
-  gasCounter,
-  MemoryBuilder,
-  Registers,
-  tryAsGas,
-  tryAsMemoryIndex,
-  tryAsSbrkIndex,
-} from "@typeberry/pvm-interpreter";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter, MemoryBuilder, tryAsMemoryIndex, tryAsSbrkIndex } from "@typeberry/pvm-interpreter";
 import { OK, Result } from "@typeberry/utils";
 import { type MachineId, PeekPokeError, tryAsMachineId } from "../externalities/refine-externalities.js";
 import { TestRefineExt } from "../externalities/refine-externalities.test.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Peek } from "./peek.js";
 
 const gas = gasCounter(tryAsGas(0));
 const RESULT_REG = 7;
 
 function prepareRegsAndMemory(machineId: MachineId, destinationStart: number, sourceStart: number, length: number) {
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(7, machineId);
   registers.set(8, tryAsU64(destinationStart));
   registers.set(9, tryAsU64(sourceStart));
   registers.set(10, tryAsU64(length));
 
   const builder = new MemoryBuilder();
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
 
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/refine/peek.ts b/packages/jam/jam-host-calls/refine/peek.ts
index 193339ff5..ed12a9d21 100644
--- a/packages/jam/jam-host-calls/refine/peek.ts
+++ b/packages/jam/jam-host-calls/refine/peek.ts
@@ -1,12 +1,12 @@
 import {
   type HostCallHandler,
-  type IHostCallMemory,
-  type IHostCallRegisters,
+  type HostCallMemory,
+  type HostCallRegisters,
   PvmExecution,
   traceRegisters,
   tryAsHostCallIndex,
 } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { assertNever, resultToString } from "@typeberry/utils";
 import { PeekPokeError, type RefineExternalities, tryAsMachineId } from "../externalities/refine-externalities.js";
 import { logger } from "../logger.js";
@@ -28,11 +28,7 @@ export class Peek implements HostCallHandler {
 
   constructor(private readonly refine: RefineExternalities) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<PvmExecution | undefined> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<PvmExecution | undefined> {
     // `n`: machine index
     const machineIndex = tryAsMachineId(regs.get(IN_OUT_REG));
     // `o`: destination memory start (local)
diff --git a/packages/jam/jam-host-calls/refine/poke.test.ts b/packages/jam/jam-host-calls/refine/poke.test.ts
index 44056dda3..bf6548e02 100644
--- a/packages/jam/jam-host-calls/refine/poke.test.ts
+++ b/packages/jam/jam-host-calls/refine/poke.test.ts
@@ -3,36 +3,31 @@ import { describe, it } from "node:test";
 import { tryAsServiceId } from "@typeberry/block";
 import { tryAsU64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import {
-  gasCounter,
-  MemoryBuilder,
-  Registers,
-  tryAsGas,
-  tryAsMemoryIndex,
-  tryAsSbrkIndex,
-} from "@typeberry/pvm-interpreter";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter, MemoryBuilder, tryAsMemoryIndex, tryAsSbrkIndex } from "@typeberry/pvm-interpreter";
 import { OK, Result } from "@typeberry/utils";
 import { type MachineId, PeekPokeError, tryAsMachineId } from "../externalities/refine-externalities.js";
 import { TestRefineExt } from "../externalities/refine-externalities.test.js";
 import { HostCallResult } from "../results.js";
+import { emptyRegistersBuffer } from "../utils.js";
 import { Poke } from "./poke.js";
 
 const gas = gasCounter(tryAsGas(0));
 const RESULT_REG = 7;
 
 function prepareRegsAndMemory(machineId: MachineId, sourceStart: number, destinationStart: number, length: number) {
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(7, machineId);
   registers.set(8, tryAsU64(sourceStart));
   registers.set(9, tryAsU64(destinationStart));
   registers.set(10, tryAsU64(length));
 
   const builder = new MemoryBuilder();
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
 
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/refine/poke.ts b/packages/jam/jam-host-calls/refine/poke.ts
index 9fe5a21e9..0dfaf2d5b 100644
--- a/packages/jam/jam-host-calls/refine/poke.ts
+++ b/packages/jam/jam-host-calls/refine/poke.ts
@@ -1,12 +1,12 @@
 import {
   type HostCallHandler,
-  type IHostCallMemory,
-  type IHostCallRegisters,
+  type HostCallMemory,
+  type HostCallRegisters,
   PvmExecution,
   traceRegisters,
   tryAsHostCallIndex,
 } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import { assertNever, resultToString } from "@typeberry/utils";
 import { PeekPokeError, type RefineExternalities, tryAsMachineId } from "../externalities/refine-externalities.js";
 import { logger } from "../logger.js";
@@ -28,11 +28,7 @@ export class Poke implements HostCallHandler {
 
   constructor(private readonly refine: RefineExternalities) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<PvmExecution | undefined> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<PvmExecution | undefined> {
     // `n`: machine index
     const machineIndex = tryAsMachineId(regs.get(IN_OUT_REG));
     // `s`: source memory start (nested vm)
diff --git a/packages/jam/jam-host-calls/utils.ts b/packages/jam/jam-host-calls/utils.ts
index e35108b6c..e964f6970 100644
--- a/packages/jam/jam-host-calls/utils.ts
+++ b/packages/jam/jam-host-calls/utils.ts
@@ -1,7 +1,8 @@
 import { type ServiceId, tryAsServiceId } from "@typeberry/block";
 import { tryAsU32, tryAsU64, type U32, type U64, u32AsLeBytes, u64IntoParts } from "@typeberry/numbers";
-import type { IHostCallRegisters } from "@typeberry/pvm-host-calls";
-import { check } from "@typeberry/utils";
+import type { HostCallRegisters } from "@typeberry/pvm-host-calls";
+import { NO_OF_REGISTERS, REGISTER_BYTE_SIZE } from "@typeberry/pvm-interface";
+import { check, safeAllocUint8Array } from "@typeberry/utils";
 
 const MAX_U32 = tryAsU32(2 ** 32 - 1);
 const MAX_U32_BIG_INT = tryAsU64(MAX_U32);
@@ -10,7 +11,7 @@ export const CURRENT_SERVICE_ID = tryAsServiceId(2 ** 32 - 1);
 
 export function getServiceIdOrCurrent(
   regNumber: number,
-  regs: IHostCallRegisters,
+  regs: HostCallRegisters,
   currentServiceId: ServiceId,
 ): ServiceId | null {
   const regValue = regs.get(regNumber);
@@ -40,3 +41,7 @@ export function writeServiceIdAsLeBytes(serviceId: ServiceId, destination: Uint8
 export function clampU64ToU32(value: U64): U32 {
   return value > MAX_U32_BIG_INT ? MAX_U32 : tryAsU32(Number(value));
 }
+
+export function emptyRegistersBuffer(): Uint8Array {
+  return safeAllocUint8Array(NO_OF_REGISTERS * REGISTER_BYTE_SIZE);
+}
diff --git a/packages/jam/jam-host-calls/write.test.ts b/packages/jam/jam-host-calls/write.test.ts
index 16575cc35..43280382d 100644
--- a/packages/jam/jam-host-calls/write.test.ts
+++ b/packages/jam/jam-host-calls/write.test.ts
@@ -4,8 +4,8 @@ import { type ServiceId, tryAsServiceGas, tryAsServiceId, tryAsTimeSlot } from "
 import { Bytes, BytesBlob } from "@typeberry/bytes";
 import { tryAsU32, tryAsU64 } from "@typeberry/numbers";
 import { HostCallMemory, HostCallRegisters, PvmExecution } from "@typeberry/pvm-host-calls";
-import { Registers } from "@typeberry/pvm-interpreter";
-import { gasCounter, tryAsGas } from "@typeberry/pvm-interpreter/gas.js";
+import { tryAsGas } from "@typeberry/pvm-interface";
+import { gasCounter } from "@typeberry/pvm-interpreter";
 import { MemoryBuilder, tryAsMemoryIndex } from "@typeberry/pvm-interpreter/memory/index.js";
 import { tryAsSbrkIndex } from "@typeberry/pvm-interpreter/memory/memory-index.js";
 import { PAGE_SIZE } from "@typeberry/pvm-spi-decoder/memory-conts.js";
@@ -13,6 +13,7 @@ import { ServiceAccountInfo } from "@typeberry/state";
 import { asOpaqueType } from "@typeberry/utils";
 import { TestAccounts } from "./externalities/test-accounts.js";
 import { HostCallResult } from "./results.js";
+import { emptyRegistersBuffer } from "./utils.js";
 import { Write } from "./write.js";
 
 const gas = gasCounter(tryAsGas(0));
@@ -52,7 +53,7 @@ function prepareRegsAndMemory(
 ) {
   const keyAddress = 2 ** 18;
   const memStart = 2 ** 16;
-  const registers = new HostCallRegisters(new Registers());
+  const registers = new HostCallRegisters(emptyRegistersBuffer());
   registers.set(KEY_START_REG, tryAsU64(keyAddress));
   registers.set(KEY_LEN_REG, tryAsU64(key.length));
   registers.set(DEST_START_REG, tryAsU64(memStart));
@@ -65,10 +66,10 @@ function prepareRegsAndMemory(
   if (!skipValue && dataInMemory.length > 0) {
     builder.setReadablePages(tryAsMemoryIndex(memStart), tryAsMemoryIndex(memStart + PAGE_SIZE), dataInMemory.raw);
   }
-  const memory = builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0));
+  const memory = new HostCallMemory(builder.finalize(tryAsMemoryIndex(0), tryAsSbrkIndex(0)));
   return {
     registers,
-    memory: new HostCallMemory(memory),
+    memory,
   };
 }
 
diff --git a/packages/jam/jam-host-calls/write.ts b/packages/jam/jam-host-calls/write.ts
index 2df4cf52c..e8c475893 100644
--- a/packages/jam/jam-host-calls/write.ts
+++ b/packages/jam/jam-host-calls/write.ts
@@ -1,9 +1,9 @@
 import type { ServiceId } from "@typeberry/block";
 import { BytesBlob } from "@typeberry/bytes";
 import { tryAsU64 } from "@typeberry/numbers";
-import type { HostCallHandler, IHostCallMemory, IHostCallRegisters } from "@typeberry/pvm-host-calls";
+import type { HostCallHandler, HostCallMemory, HostCallRegisters } from "@typeberry/pvm-host-calls";
 import { PvmExecution, traceRegisters, tryAsHostCallIndex } from "@typeberry/pvm-host-calls";
-import { type GasCounter, tryAsSmallGas } from "@typeberry/pvm-interpreter/gas.js";
+import { type IGasCounter, tryAsSmallGas } from "@typeberry/pvm-interface";
 import type { StorageKey } from "@typeberry/state";
 import { asOpaqueType, type Result, resultToString, safeAllocUint8Array } from "@typeberry/utils";
 import { logger } from "./logger.js";
@@ -41,11 +41,7 @@ export class Write implements HostCallHandler {
     private readonly account: AccountsWrite,
   ) {}
 
-  async execute(
-    _gas: GasCounter,
-    regs: IHostCallRegisters,
-    memory: IHostCallMemory,
-  ): Promise<undefined | PvmExecution> {
+  async execute(_gas: IGasCounter, regs: HostCallRegisters, memory: HostCallMemory): Promise<undefined | PvmExecution> {
     // k_0
     const storageKeyStartAddress = regs.get(IN_OUT_REG);
     // k_z
diff --git a/packages/jam/node/jam-config.ts b/packages/jam/node/jam-config.ts
index 524ca9e07..836f014d0 100644
--- a/packages/jam/node/jam-config.ts
+++ b/packages/jam/node/jam-config.ts
@@ -5,7 +5,7 @@ import {
   tryAsValidatorIndex,
   type ValidatorIndex,
 } from "@typeberry/block";
-import type { Bootnode } from "@typeberry/config";
+import type { Bootnode, PvmBackend } from "@typeberry/config";
 import type { NodeConfiguration } from "@typeberry/config-node";
 import type { Ed25519SecretSeed, KeySeed } from "@typeberry/crypto/key-derivation.js";
 
@@ -23,6 +23,7 @@ export class JamConfig {
     isAuthoring,
     nodeName,
     nodeConfig,
+    pvmBackend,
     devConfig = null,
     networkConfig = null,
     ancestry = [],
@@ -30,11 +31,12 @@ export class JamConfig {
     isAuthoring?: boolean;
     nodeName: string;
     nodeConfig: NodeConfiguration;
+    pvmBackend: PvmBackend;
     devConfig?: DevConfig | null;
     networkConfig?: NetworkConfig | null;
     ancestry?: [HeaderHash, TimeSlot][];
   }) {
-    return new JamConfig(isAuthoring ?? false, nodeName, nodeConfig, devConfig, networkConfig, ancestry);
+    return new JamConfig(isAuthoring ?? false, nodeName, nodeConfig, pvmBackend, devConfig, networkConfig, ancestry);
   }
 
   private constructor(
@@ -44,6 +46,8 @@ export class JamConfig {
     public readonly nodeName: string,
     /** Node starting configuration. */
     public readonly node: NodeConfiguration,
+    /** PVM execution engine. */
+    public readonly pvmBackend: PvmBackend,
     /** Developer specific configuration. */
     public readonly dev: DevConfig | null,
     /** Networking options. */
diff --git a/packages/jam/node/main-fuzz.ts b/packages/jam/node/main-fuzz.ts
index 06f0155ad..e02fbbdc5 100644
--- a/packages/jam/node/main-fuzz.ts
+++ b/packages/jam/node/main-fuzz.ts
@@ -31,6 +31,7 @@ export function getFuzzDetails() {
 
 export async function mainFuzz(fuzzConfig: FuzzConfig, withRelPath: (v: string) => string) {
   logger.info`💨 Fuzzer V${fuzzConfig.version} starting up.`;
+  logger.info`🖥️ PVM Backend: ${fuzzConfig.jamNodeConfig.pvmBackend}.`;
 
   const { jamNodeConfig: config } = fuzzConfig;
 
diff --git a/packages/jam/node/main-importer.ts b/packages/jam/node/main-importer.ts
index 9aae545c9..93ddf97ec 100644
--- a/packages/jam/node/main-importer.ts
+++ b/packages/jam/node/main-importer.ts
@@ -17,6 +17,7 @@ export async function mainImporter(config: JamConfig, withRelPath: (v: string) =
 
   logger.info`🫐 Typeberry ${packageJson.version}. GP: ${CURRENT_VERSION} (${CURRENT_SUITE})`;
   logger.info`🎸 Starting importer: ${config.nodeName}.`;
+  logger.info`🖥️ PVM Backend: ${config.pvmBackend}.`;
   const chainSpec = getChainSpec(config.node.flavor);
   const blake2b = await Blake2b.createHasher();
   const omitSealVerification = false;
@@ -34,6 +35,7 @@ export async function mainImporter(config: JamConfig, withRelPath: (v: string) =
           chainSpec,
           blake2b,
           workerParams: {
+            pvm: config.pvmBackend,
             omitSealVerification,
           },
         })
@@ -42,6 +44,7 @@ export async function mainImporter(config: JamConfig, withRelPath: (v: string) =
           blake2b,
           dbPath,
           workerParams: {
+            pvm: config.pvmBackend,
             omitSealVerification,
           },
         });
diff --git a/packages/jam/node/main.ts b/packages/jam/node/main.ts
index 6b29b7a76..3ed96d018 100755
--- a/packages/jam/node/main.ts
+++ b/packages/jam/node/main.ts
@@ -33,6 +33,7 @@ export async function main(config: JamConfig, withRelPath: (v: string) => string
 
   logger.info`🫐 Typeberry ${packageJson.version}. GP: ${CURRENT_VERSION} (${CURRENT_SUITE})`;
   logger.info`🎸 Starting node: ${config.nodeName}.`;
+  logger.info`🖥️ PVM Backend: ${config.pvmBackend}.`;
   const chainSpec = getChainSpec(config.node.flavor);
   const blake2b = await Blake2b.createHasher();
   if (config.node.databaseBasePath === undefined) {
@@ -50,6 +51,7 @@ export async function main(config: JamConfig, withRelPath: (v: string) => string
   const importerConfig = LmdbWorkerConfig.new({
     ...baseConfig,
     workerParams: ImporterConfig.create({
+      pvm: config.pvmBackend,
       omitSealVerification: config.node.authorship.omitSealVerification,
     }),
   });
diff --git a/packages/jam/transition/accumulate/accumulate.test.ts b/packages/jam/transition/accumulate/accumulate.test.ts
index f7c4705d9..4f74961d4 100644
--- a/packages/jam/transition/accumulate/accumulate.test.ts
+++ b/packages/jam/transition/accumulate/accumulate.test.ts
@@ -19,7 +19,7 @@ import { WorkPackageSpec, WorkReport } from "@typeberry/block/work-report.js";
 import { WorkExecResult, WorkExecResultKind, WorkRefineLoad, WorkResult } from "@typeberry/block/work-result.js";
 import { Bytes, BytesBlob } from "@typeberry/bytes";
 import { asKnownSize, FixedSizeArray, HashDictionary, HashSet } from "@typeberry/collections";
-import { type ChainSpec, tinyChainSpec } from "@typeberry/config";
+import { type ChainSpec, PvmBackend, PvmBackendNames, tinyChainSpec } from "@typeberry/config";
 import { Blake2b, HASH_SIZE, type OpaqueHash } from "@typeberry/hash";
 import { tryAsU16, tryAsU32, tryAsU64 } from "@typeberry/numbers";
 import {
@@ -46,271 +46,273 @@ type TestServiceInfo = {
   lastAccumulation?: TimeSlot;
 };
 
-describe("accumulate", () => {
-  // based on tiny/enqueue_and_unlock_chain_wraps-5.json
-  it("should do correct state transition", async () => {
-    const entropy = hashFromString<EntropyHash>("0xae85d6635e9ae539d0846b911ec86a27fe000f619b78bcac8a74b77e36f6dbcf");
+[PvmBackend.BuiltIn, PvmBackend.Ananas].forEach((pvm) => {
+  describe(`accumulate: ${PvmBackendNames[pvm]}`, () => {
+    // based on tiny/enqueue_and_unlock_chain_wraps-5.json
+    it("should do correct state transition", async () => {
+      const entropy = hashFromString<EntropyHash>("0xae85d6635e9ae539d0846b911ec86a27fe000f619b78bcac8a74b77e36f6dbcf");
 
-    const input: AccumulateInput = {
-      reports: [
-        createWorkReport(hashFromString("0xdf49de52326d7d3c99391cdd32b2ca7c06398e798b520970347160ecf8d9ce32")),
-        createWorkReport(hashFromString("0xd3d0ac423a2e9451db2e88bd75cc143b19424747fbcf2696792987436e8722a6")),
-      ],
-      slot: tryAsTimeSlot(47),
-      entropy,
-    };
+      const input: AccumulateInput = {
+        reports: [
+          createWorkReport(hashFromString("0xdf49de52326d7d3c99391cdd32b2ca7c06398e798b520970347160ecf8d9ce32")),
+          createWorkReport(hashFromString("0xd3d0ac423a2e9451db2e88bd75cc143b19424747fbcf2696792987436e8722a6")),
+        ],
+        slot: tryAsTimeSlot(47),
+        entropy,
+      };
 
-    const services = createServices([
-      [
-        tryAsServiceId(1729),
-        hashFromString("0x3ecc56accce719e5214e8dbb034f49d5cf0c6942da3e5f3f047d1693cc60c74a"),
-        preimageBlob,
-        { lastAccumulation: undefined },
-      ],
-    ]);
-    const state = InMemoryState.partial(tinyChainSpec, {
-      timeslot: tryAsTimeSlot(46),
-      services,
-      privilegedServices: createPrivilegedServices(tinyChainSpec),
-      recentlyAccumulated: tryAsPerEpochBlock(
+      const services = createServices([
         [
-          [],
-          [],
-          [],
-          [],
-          [],
-          ["0x04f5f2b6509d847d49487d5db1275e8105225018952c7aec9d2d90f039c50e45"],
-          ["0x506524cb141b83715705c05983d17ebc7760c64d2ce81f15b6bc2dd1eeb55551"],
-          ["0x7bbdd7961afb2db642f7cdb87021fb053c67d2ac79d69a87fc9fbcf6786e30b9"],
-          [],
-          ["0x07b08ccece1b01a9202152a6fa99d23cf0160da721374ccaabd40885d8fc15d3"],
-          [],
-          ["0x9d7588b469d529d9a058c12bef3ce96106babf54aa3ba251066832cd160aa2c6"],
-        ].map((x) => HashSet.from(x.map((x) => hashFromString<WorkPackageHash>(x)))),
-        tinyChainSpec,
-      ),
-      accumulationQueue: tryAsPerEpochBlock(
-        [
-          [],
-          [
-            createNotAccumulatedWorkReport(
-              hashFromString("0xa7a66c1635f45e0413cec365f60fb46fa0489c4d2df75f6fd9c00d1da3729222"),
-              [hashFromString("0x38b7a75bd6d296f01fc6b4b6569c38980af6ba2ea34e22d429cccfb6f5b7432a")],
-              [hashFromString("0x38b7a75bd6d296f01fc6b4b6569c38980af6ba2ea34e22d429cccfb6f5b7432a")],
-              tryAsServiceId(1729),
-            ),
-          ],
-          [],
-          [],
-          [],
-          [],
-          [
-            createNotAccumulatedWorkReport(
-              hashFromString("0x38b7a75bd6d296f01fc6b4b6569c38980af6ba2ea34e22d429cccfb6f5b7432a"),
-              [hashFromString("0x17e5809e4d5e9daf50361fb6557a00814301159fc81a39cd4d2687e110e0b7be")],
-              [hashFromString("0x17e5809e4d5e9daf50361fb6557a00814301159fc81a39cd4d2687e110e0b7be")],
-              tryAsServiceId(1729),
-            ),
-            createNotAccumulatedWorkReport(
-              hashFromString("0x17e5809e4d5e9daf50361fb6557a00814301159fc81a39cd4d2687e110e0b7be"),
-              [hashFromString("0x36a748779db31316ac26eebc08dadbeda8a8d4794892f6e340e32ab69e0d4d80")],
-              [hashFromString("0x36a748779db31316ac26eebc08dadbeda8a8d4794892f6e340e32ab69e0d4d80")],
-              tryAsServiceId(1729),
-            ),
-          ],
-          [],
-          [],
-          [],
+          tryAsServiceId(1729),
+          hashFromString("0x3ecc56accce719e5214e8dbb034f49d5cf0c6942da3e5f3f047d1693cc60c74a"),
+          preimageBlob,
+          { lastAccumulation: undefined },
+        ],
+      ]);
+      const state = InMemoryState.partial(tinyChainSpec, {
+        timeslot: tryAsTimeSlot(46),
+        services,
+        privilegedServices: createPrivilegedServices(tinyChainSpec),
+        recentlyAccumulated: tryAsPerEpochBlock(
           [
-            createNotAccumulatedWorkReport(
-              hashFromString("0x36a748779db31316ac26eebc08dadbeda8a8d4794892f6e340e32ab69e0d4d80"),
-              [hashFromString("0xd3d0ac423a2e9451db2e88bd75cc143b19424747fbcf2696792987436e8722a6")],
-              [hashFromString("0xd3d0ac423a2e9451db2e88bd75cc143b19424747fbcf2696792987436e8722a6")],
-              tryAsServiceId(1729),
-            ),
-          ],
+            [],
+            [],
+            [],
+            [],
+            [],
+            ["0x04f5f2b6509d847d49487d5db1275e8105225018952c7aec9d2d90f039c50e45"],
+            ["0x506524cb141b83715705c05983d17ebc7760c64d2ce81f15b6bc2dd1eeb55551"],
+            ["0x7bbdd7961afb2db642f7cdb87021fb053c67d2ac79d69a87fc9fbcf6786e30b9"],
+            [],
+            ["0x07b08ccece1b01a9202152a6fa99d23cf0160da721374ccaabd40885d8fc15d3"],
+            [],
+            ["0x9d7588b469d529d9a058c12bef3ce96106babf54aa3ba251066832cd160aa2c6"],
+          ].map((x) => HashSet.from(x.map((x) => hashFromString<WorkPackageHash>(x)))),
+          tinyChainSpec,
+        ),
+        accumulationQueue: tryAsPerEpochBlock(
           [
-            createNotAccumulatedWorkReport(
-              hashFromString("0x18176cfbff4a8b40f2d9cba3c2ddc4a5b75e9152c8c41452cda90bebc0632013"),
-              [hashFromString("0xa7a66c1635f45e0413cec365f60fb46fa0489c4d2df75f6fd9c00d1da3729222")],
-              [hashFromString("0xa7a66c1635f45e0413cec365f60fb46fa0489c4d2df75f6fd9c00d1da3729222")],
-              tryAsServiceId(1729),
-            ),
-            createNotAccumulatedWorkReport(
-              hashFromString("0xf5983aaa6fe1e7428902ace29d14be81a664a65f6dfca1138ccb99136547324e"),
-              [hashFromString("0x18176cfbff4a8b40f2d9cba3c2ddc4a5b75e9152c8c41452cda90bebc0632013")],
-              [hashFromString("0x18176cfbff4a8b40f2d9cba3c2ddc4a5b75e9152c8c41452cda90bebc0632013")],
-              tryAsServiceId(1729),
-            ),
+            [],
+            [
+              createNotAccumulatedWorkReport(
+                hashFromString("0xa7a66c1635f45e0413cec365f60fb46fa0489c4d2df75f6fd9c00d1da3729222"),
+                [hashFromString("0x38b7a75bd6d296f01fc6b4b6569c38980af6ba2ea34e22d429cccfb6f5b7432a")],
+                [hashFromString("0x38b7a75bd6d296f01fc6b4b6569c38980af6ba2ea34e22d429cccfb6f5b7432a")],
+                tryAsServiceId(1729),
+              ),
+            ],
+            [],
+            [],
+            [],
+            [],
+            [
+              createNotAccumulatedWorkReport(
+                hashFromString("0x38b7a75bd6d296f01fc6b4b6569c38980af6ba2ea34e22d429cccfb6f5b7432a"),
+                [hashFromString("0x17e5809e4d5e9daf50361fb6557a00814301159fc81a39cd4d2687e110e0b7be")],
+                [hashFromString("0x17e5809e4d5e9daf50361fb6557a00814301159fc81a39cd4d2687e110e0b7be")],
+                tryAsServiceId(1729),
+              ),
+              createNotAccumulatedWorkReport(
+                hashFromString("0x17e5809e4d5e9daf50361fb6557a00814301159fc81a39cd4d2687e110e0b7be"),
+                [hashFromString("0x36a748779db31316ac26eebc08dadbeda8a8d4794892f6e340e32ab69e0d4d80")],
+                [hashFromString("0x36a748779db31316ac26eebc08dadbeda8a8d4794892f6e340e32ab69e0d4d80")],
+                tryAsServiceId(1729),
+              ),
+            ],
+            [],
+            [],
+            [],
+            [
+              createNotAccumulatedWorkReport(
+                hashFromString("0x36a748779db31316ac26eebc08dadbeda8a8d4794892f6e340e32ab69e0d4d80"),
+                [hashFromString("0xd3d0ac423a2e9451db2e88bd75cc143b19424747fbcf2696792987436e8722a6")],
+                [hashFromString("0xd3d0ac423a2e9451db2e88bd75cc143b19424747fbcf2696792987436e8722a6")],
+                tryAsServiceId(1729),
+              ),
+            ],
+            [
+              createNotAccumulatedWorkReport(
+                hashFromString("0x18176cfbff4a8b40f2d9cba3c2ddc4a5b75e9152c8c41452cda90bebc0632013"),
+                [hashFromString("0xa7a66c1635f45e0413cec365f60fb46fa0489c4d2df75f6fd9c00d1da3729222")],
+                [hashFromString("0xa7a66c1635f45e0413cec365f60fb46fa0489c4d2df75f6fd9c00d1da3729222")],
+                tryAsServiceId(1729),
+              ),
+              createNotAccumulatedWorkReport(
+                hashFromString("0xf5983aaa6fe1e7428902ace29d14be81a664a65f6dfca1138ccb99136547324e"),
+                [hashFromString("0x18176cfbff4a8b40f2d9cba3c2ddc4a5b75e9152c8c41452cda90bebc0632013")],
+                [hashFromString("0x18176cfbff4a8b40f2d9cba3c2ddc4a5b75e9152c8c41452cda90bebc0632013")],
+                tryAsServiceId(1729),
+              ),
+            ],
           ],
-        ],
-        tinyChainSpec,
-      ),
-    });
+          tinyChainSpec,
+        ),
+      });
 
-    const expectedServices = createServices([
-      [
-        tryAsServiceId(1729),
-        hashFromString("0x3ecc56accce719e5214e8dbb034f49d5cf0c6942da3e5f3f047d1693cc60c74a"),
-        preimageBlob,
-        { lastAccumulation: tryAsTimeSlot(47) },
-      ],
-    ]);
-    const expectedState: AccumulateState = InMemoryState.partial(tinyChainSpec, {
-      timeslot: input.slot,
-      services: expectedServices,
-      privilegedServices: state.privilegedServices,
-      recentlyAccumulated: tryAsPerEpochBlock(
+      const expectedServices = createServices([
         [
-          [],
-          [],
-          [],
-          [],
-          ["0x04f5f2b6509d847d49487d5db1275e8105225018952c7aec9d2d90f039c50e45"],
-          ["0x506524cb141b83715705c05983d17ebc7760c64d2ce81f15b6bc2dd1eeb55551"],
-          ["0x7bbdd7961afb2db642f7cdb87021fb053c67d2ac79d69a87fc9fbcf6786e30b9"],
-          [],
-          ["0x07b08ccece1b01a9202152a6fa99d23cf0160da721374ccaabd40885d8fc15d3"],
-          [],
-          ["0x9d7588b469d529d9a058c12bef3ce96106babf54aa3ba251066832cd160aa2c6"],
+          tryAsServiceId(1729),
+          hashFromString("0x3ecc56accce719e5214e8dbb034f49d5cf0c6942da3e5f3f047d1693cc60c74a"),
+          preimageBlob,
+          { lastAccumulation: tryAsTimeSlot(47) },
+        ],
+      ]);
+      const expectedState: AccumulateState = InMemoryState.partial(tinyChainSpec, {
+        timeslot: input.slot,
+        services: expectedServices,
+        privilegedServices: state.privilegedServices,
+        recentlyAccumulated: tryAsPerEpochBlock(
           [
-            "0x17e5809e4d5e9daf50361fb6557a00814301159fc81a39cd4d2687e110e0b7be",
-            "0x18176cfbff4a8b40f2d9cba3c2ddc4a5b75e9152c8c41452cda90bebc0632013",
-            "0x36a748779db31316ac26eebc08dadbeda8a8d4794892f6e340e32ab69e0d4d80",
-            "0x38b7a75bd6d296f01fc6b4b6569c38980af6ba2ea34e22d429cccfb6f5b7432a",
-            "0xa7a66c1635f45e0413cec365f60fb46fa0489c4d2df75f6fd9c00d1da3729222",
-            "0xd3d0ac423a2e9451db2e88bd75cc143b19424747fbcf2696792987436e8722a6",
-            "0xdf49de52326d7d3c99391cdd32b2ca7c06398e798b520970347160ecf8d9ce32",
-            "0xf5983aaa6fe1e7428902ace29d14be81a664a65f6dfca1138ccb99136547324e",
-          ],
-        ].map((x) => HashSet.from(x.map((x) => hashFromString<WorkPackageHash>(x)))),
-        tinyChainSpec,
-      ),
-      accumulationQueue: tryAsPerEpochBlock([[], [], [], [], [], [], [], [], [], [], [], []], tinyChainSpec),
-    });
-    const expectedOutput: AccumulationOutput[] = [];
-    const accumulate = new Accumulate(tinyChainSpec, blake2b, state);
+            [],
+            [],
+            [],
+            [],
+            ["0x04f5f2b6509d847d49487d5db1275e8105225018952c7aec9d2d90f039c50e45"],
+            ["0x506524cb141b83715705c05983d17ebc7760c64d2ce81f15b6bc2dd1eeb55551"],
+            ["0x7bbdd7961afb2db642f7cdb87021fb053c67d2ac79d69a87fc9fbcf6786e30b9"],
+            [],
+            ["0x07b08ccece1b01a9202152a6fa99d23cf0160da721374ccaabd40885d8fc15d3"],
+            [],
+            ["0x9d7588b469d529d9a058c12bef3ce96106babf54aa3ba251066832cd160aa2c6"],
+            [
+              "0x17e5809e4d5e9daf50361fb6557a00814301159fc81a39cd4d2687e110e0b7be",
+              "0x18176cfbff4a8b40f2d9cba3c2ddc4a5b75e9152c8c41452cda90bebc0632013",
+              "0x36a748779db31316ac26eebc08dadbeda8a8d4794892f6e340e32ab69e0d4d80",
+              "0x38b7a75bd6d296f01fc6b4b6569c38980af6ba2ea34e22d429cccfb6f5b7432a",
+              "0xa7a66c1635f45e0413cec365f60fb46fa0489c4d2df75f6fd9c00d1da3729222",
+              "0xd3d0ac423a2e9451db2e88bd75cc143b19424747fbcf2696792987436e8722a6",
+              "0xdf49de52326d7d3c99391cdd32b2ca7c06398e798b520970347160ecf8d9ce32",
+              "0xf5983aaa6fe1e7428902ace29d14be81a664a65f6dfca1138ccb99136547324e",
+            ],
+          ].map((x) => HashSet.from(x.map((x) => hashFromString<WorkPackageHash>(x)))),
+          tinyChainSpec,
+        ),
+        accumulationQueue: tryAsPerEpochBlock([[], [], [], [], [], [], [], [], [], [], [], []], tinyChainSpec),
+      });
+      const expectedOutput: AccumulationOutput[] = [];
+      const accumulate = new Accumulate(tinyChainSpec, blake2b, state, pvm);
 
-    // when
-    const output = await accumulate.transition(input);
-    if (output.isError) {
-      assert.fail(`Expect ok, got ${resultToString(output)}`);
-    }
-    state.applyUpdate(output.ok.stateUpdate);
+      // when
+      const output = await accumulate.transition(input);
+      if (output.isError) {
+        assert.fail(`Expect ok, got ${resultToString(output)}`);
+      }
+      state.applyUpdate(output.ok.stateUpdate);
 
-    // then
-    deepEqual(output.ok.accumulationOutputLog.array, expectedOutput);
-    deepEqual<AccumulateState>(state, expectedState);
-  });
+      // then
+      deepEqual(output.ok.accumulationOutputLog.array, expectedOutput);
+      deepEqual<AccumulateState>(state, expectedState);
+    });
 
-  it("should detect creation of duplicated service ids", async () => {
-    const services = createServices([
-      [
-        tryAsServiceId(1729),
-        hashFromString("0x3ecc56accce719e5214e8dbb034f49d5cf0c6942da3e5f3f047d1693cc60c74a"),
-        preimageBlob,
-        { lastAccumulation: undefined },
-      ],
-    ]);
-    const state = InMemoryState.partial(tinyChainSpec, {
-      timeslot: tryAsTimeSlot(46),
-      services,
-      privilegedServices: createPrivilegedServices(tinyChainSpec),
-      recentlyAccumulated: tryAsPerEpochBlock(
+    it("should detect creation of duplicated service ids", async () => {
+      const services = createServices([
         [
-          [],
-          [],
-          [],
-          [],
-          [],
-          ["0x04f5f2b6509d847d49487d5db1275e8105225018952c7aec9d2d90f039c50e45"],
-          ["0x506524cb141b83715705c05983d17ebc7760c64d2ce81f15b6bc2dd1eeb55551"],
-          ["0x7bbdd7961afb2db642f7cdb87021fb053c67d2ac79d69a87fc9fbcf6786e30b9"],
-          [],
-          ["0x07b08ccece1b01a9202152a6fa99d23cf0160da721374ccaabd40885d8fc15d3"],
-          [],
-          ["0x9d7588b469d529d9a058c12bef3ce96106babf54aa3ba251066832cd160aa2c6"],
-        ].map((x) => HashSet.from(x.map((x) => hashFromString<WorkPackageHash>(x)))),
-        tinyChainSpec,
-      ),
-      accumulationQueue: tryAsPerEpochBlock(
-        [
-          [],
-          [
-            createNotAccumulatedWorkReport(
-              hashFromString("0xa7a66c1635f45e0413cec365f60fb46fa0489c4d2df75f6fd9c00d1da3729222"),
-              [hashFromString("0x38b7a75bd6d296f01fc6b4b6569c38980af6ba2ea34e22d429cccfb6f5b7432a")],
-              [hashFromString("0x38b7a75bd6d296f01fc6b4b6569c38980af6ba2ea34e22d429cccfb6f5b7432a")],
-              tryAsServiceId(1729),
-            ),
-          ],
-          [],
-          [],
-          [],
-          [],
-          [
-            createNotAccumulatedWorkReport(
-              hashFromString("0x38b7a75bd6d296f01fc6b4b6569c38980af6ba2ea34e22d429cccfb6f5b7432a"),
-              [hashFromString("0x17e5809e4d5e9daf50361fb6557a00814301159fc81a39cd4d2687e110e0b7be")],
-              [hashFromString("0x17e5809e4d5e9daf50361fb6557a00814301159fc81a39cd4d2687e110e0b7be")],
-              tryAsServiceId(1729),
-            ),
-            createNotAccumulatedWorkReport(
-              hashFromString("0x17e5809e4d5e9daf50361fb6557a00814301159fc81a39cd4d2687e110e0b7be"),
-              [hashFromString("0x36a748779db31316ac26eebc08dadbeda8a8d4794892f6e340e32ab69e0d4d80")],
-              [hashFromString("0x36a748779db31316ac26eebc08dadbeda8a8d4794892f6e340e32ab69e0d4d80")],
-              tryAsServiceId(1729),
-            ),
-          ],
-          [],
-          [],
-          [],
+          tryAsServiceId(1729),
+          hashFromString("0x3ecc56accce719e5214e8dbb034f49d5cf0c6942da3e5f3f047d1693cc60c74a"),
+          preimageBlob,
+          { lastAccumulation: undefined },
+        ],
+      ]);
+      const state = InMemoryState.partial(tinyChainSpec, {
+        timeslot: tryAsTimeSlot(46),
+        services,
+        privilegedServices: createPrivilegedServices(tinyChainSpec),
+        recentlyAccumulated: tryAsPerEpochBlock(
           [
-            createNotAccumulatedWorkReport(
-              hashFromString("0x36a748779db31316ac26eebc08dadbeda8a8d4794892f6e340e32ab69e0d4d80"),
-              [hashFromString("0xd3d0ac423a2e9451db2e88bd75cc143b19424747fbcf2696792987436e8722a6")],
-              [hashFromString("0xd3d0ac423a2e9451db2e88bd75cc143b19424747fbcf2696792987436e8722a6")],
-              tryAsServiceId(1729),
-            ),
-          ],
+            [],
+            [],
+            [],
+            [],
+            [],
+            ["0x04f5f2b6509d847d49487d5db1275e8105225018952c7aec9d2d90f039c50e45"],
+            ["0x506524cb141b83715705c05983d17ebc7760c64d2ce81f15b6bc2dd1eeb55551"],
+            ["0x7bbdd7961afb2db642f7cdb87021fb053c67d2ac79d69a87fc9fbcf6786e30b9"],
+            [],
+            ["0x07b08ccece1b01a9202152a6fa99d23cf0160da721374ccaabd40885d8fc15d3"],
+            [],
+            ["0x9d7588b469d529d9a058c12bef3ce96106babf54aa3ba251066832cd160aa2c6"],
+          ].map((x) => HashSet.from(x.map((x) => hashFromString<WorkPackageHash>(x)))),
+          tinyChainSpec,
+        ),
+        accumulationQueue: tryAsPerEpochBlock(
           [
-            createNotAccumulatedWorkReport(
-              hashFromString("0x18176cfbff4a8b40f2d9cba3c2ddc4a5b75e9152c8c41452cda90bebc0632013"),
-              [hashFromString("0xa7a66c1635f45e0413cec365f60fb46fa0489c4d2df75f6fd9c00d1da3729222")],
-              [hashFromString("0xa7a66c1635f45e0413cec365f60fb46fa0489c4d2df75f6fd9c00d1da3729222")],
-              tryAsServiceId(1729),
-            ),
-            createNotAccumulatedWorkReport(
-              hashFromString("0xf5983aaa6fe1e7428902ace29d14be81a664a65f6dfca1138ccb99136547324e"),
-              [hashFromString("0x18176cfbff4a8b40f2d9cba3c2ddc4a5b75e9152c8c41452cda90bebc0632013")],
-              [hashFromString("0x18176cfbff4a8b40f2d9cba3c2ddc4a5b75e9152c8c41452cda90bebc0632013")],
-              tryAsServiceId(1729),
-            ),
+            [],
+            [
+              createNotAccumulatedWorkReport(
+                hashFromString("0xa7a66c1635f45e0413cec365f60fb46fa0489c4d2df75f6fd9c00d1da3729222"),
+                [hashFromString("0x38b7a75bd6d296f01fc6b4b6569c38980af6ba2ea34e22d429cccfb6f5b7432a")],
+                [hashFromString("0x38b7a75bd6d296f01fc6b4b6569c38980af6ba2ea34e22d429cccfb6f5b7432a")],
+                tryAsServiceId(1729),
+              ),
+            ],
+            [],
+            [],
+            [],
+            [],
+            [
+              createNotAccumulatedWorkReport(
+                hashFromString("0x38b7a75bd6d296f01fc6b4b6569c38980af6ba2ea34e22d429cccfb6f5b7432a"),
+                [hashFromString("0x17e5809e4d5e9daf50361fb6557a00814301159fc81a39cd4d2687e110e0b7be")],
+                [hashFromString("0x17e5809e4d5e9daf50361fb6557a00814301159fc81a39cd4d2687e110e0b7be")],
+                tryAsServiceId(1729),
+              ),
+              createNotAccumulatedWorkReport(
+                hashFromString("0x17e5809e4d5e9daf50361fb6557a00814301159fc81a39cd4d2687e110e0b7be"),
+                [hashFromString("0x36a748779db31316ac26eebc08dadbeda8a8d4794892f6e340e32ab69e0d4d80")],
+                [hashFromString("0x36a748779db31316ac26eebc08dadbeda8a8d4794892f6e340e32ab69e0d4d80")],
+                tryAsServiceId(1729),
+              ),
+            ],
+            [],
+            [],
+            [],
+            [
+              createNotAccumulatedWorkReport(
+                hashFromString("0x36a748779db31316ac26eebc08dadbeda8a8d4794892f6e340e32ab69e0d4d80"),
+                [hashFromString("0xd3d0ac423a2e9451db2e88bd75cc143b19424747fbcf2696792987436e8722a6")],
+                [hashFromString("0xd3d0ac423a2e9451db2e88bd75cc143b19424747fbcf2696792987436e8722a6")],
+                tryAsServiceId(1729),
+              ),
+            ],
+            [
+              createNotAccumulatedWorkReport(
+                hashFromString("0x18176cfbff4a8b40f2d9cba3c2ddc4a5b75e9152c8c41452cda90bebc0632013"),
+                [hashFromString("0xa7a66c1635f45e0413cec365f60fb46fa0489c4d2df75f6fd9c00d1da3729222")],
+                [hashFromString("0xa7a66c1635f45e0413cec365f60fb46fa0489c4d2df75f6fd9c00d1da3729222")],
+                tryAsServiceId(1729),
+              ),
+              createNotAccumulatedWorkReport(
+                hashFromString("0xf5983aaa6fe1e7428902ace29d14be81a664a65f6dfca1138ccb99136547324e"),
+                [hashFromString("0x18176cfbff4a8b40f2d9cba3c2ddc4a5b75e9152c8c41452cda90bebc0632013")],
+                [hashFromString("0x18176cfbff4a8b40f2d9cba3c2ddc4a5b75e9152c8c41452cda90bebc0632013")],
+                tryAsServiceId(1729),
+              ),
+            ],
           ],
-        ],
-        tinyChainSpec,
-      ),
-    });
+          tinyChainSpec,
+        ),
+      });
 
-    const accumulate = new Accumulate(tinyChainSpec, blake2b, state);
+      const accumulate = new Accumulate(tinyChainSpec, blake2b, state, pvm);
 
-    const mod = 2 ** 32 - MIN_PUBLIC_SERVICE_INDEX - 2 ** 8;
-    const offset = MIN_PUBLIC_SERVICE_INDEX;
+      const mod = 2 ** 32 - MIN_PUBLIC_SERVICE_INDEX - 2 ** 8;
+      const offset = MIN_PUBLIC_SERVICE_INDEX;
 
-    const createdIds: ServiceId[] = [];
-    let currentId = tryAsServiceId(0);
+      const createdIds: ServiceId[] = [];
+      let currentId = tryAsServiceId(0);
 
-    for (let i = 0; i < 10; i++) {
-      createdIds.push(currentId);
-      currentId = tryAsServiceId(((currentId - offset + 1 + mod) % mod) + offset);
-    }
+      for (let i = 0; i < 10; i++) {
+        createdIds.push(currentId);
+        currentId = tryAsServiceId(((currentId - offset + 1 + mod) % mod) + offset);
+      }
 
-    // create no duplications
-    assert.ok(!accumulate.hasDuplicatedServiceIdCreated(createdIds), "Should not trigger duplicated service id!");
+      // create no duplications
+      assert.ok(!accumulate.hasDuplicatedServiceIdCreated(createdIds), "Should not trigger duplicated service id!");
 
-    // create duplication
-    createdIds.push(tryAsServiceId(0));
-    assert.ok(accumulate.hasDuplicatedServiceIdCreated(createdIds), "Should detect duplicated service id!");
+      // create duplication
+      createdIds.push(tryAsServiceId(0));
+      assert.ok(accumulate.hasDuplicatedServiceIdCreated(createdIds), "Should detect duplicated service id!");
+    });
   });
 });
 
diff --git a/packages/jam/transition/accumulate/accumulate.ts b/packages/jam/transition/accumulate/accumulate.ts
index 6fd135717..f485fef0e 100644
--- a/packages/jam/transition/accumulate/accumulate.ts
+++ b/packages/jam/transition/accumulate/accumulate.ts
@@ -11,7 +11,7 @@ import type { WorkReport } from "@typeberry/block/work-report.js";
 import { Bytes } from "@typeberry/bytes";
 import { codec, Encoder } from "@typeberry/codec";
 import { ArrayView, HashSet, SortedArray } from "@typeberry/collections";
-import type { ChainSpec } from "@typeberry/config";
+import type { ChainSpec, PvmBackend } from "@typeberry/config";
 import { type Blake2b, HASH_SIZE } from "@typeberry/hash";
 import type { PendingTransfer } from "@typeberry/jam-host-calls";
 import {
@@ -20,8 +20,7 @@ import {
 } from "@typeberry/jam-host-calls/externalities/state-update.js";
 import { Logger } from "@typeberry/logger";
 import { sumU64, tryAsU32, type U32 } from "@typeberry/numbers";
-import { tryAsGas } from "@typeberry/pvm-interpreter";
-import { Status } from "@typeberry/pvm-interpreter/status.js";
+import { Status, tryAsGas } from "@typeberry/pvm-interface";
 import {
   type AccumulationOutput,
   type AutoAccumulate,
@@ -86,6 +85,7 @@ export class Accumulate {
     public readonly chainSpec: ChainSpec,
     public readonly blake2b: Blake2b,
     public readonly state: AccumulateState,
+    public readonly pvm: PvmBackend,
   ) {}
 
   /**
@@ -171,7 +171,14 @@ export class Accumulate {
       fetchExternalities,
     };
 
-    const executor = PvmExecutor.createAccumulateExecutor(serviceId, code, externalities, this.chainSpec);
+    const executor = await PvmExecutor.createAccumulateExecutor(
+      serviceId,
+      code,
+      externalities,
+      this.chainSpec,
+      this.pvm,
+    );
+
     const invocationArgs = Encoder.encodeObject(ARGS_CODEC, {
       slot,
       serviceId,
diff --git a/packages/jam/transition/accumulate/deferred-transfers.ts b/packages/jam/transition/accumulate/deferred-transfers.ts
index 9df12d3d6..2ecf23eaf 100644
--- a/packages/jam/transition/accumulate/deferred-transfers.ts
+++ b/packages/jam/transition/accumulate/deferred-transfers.ts
@@ -1,7 +1,7 @@
 import { type EntropyHash, type ServiceId, type TimeSlot, tryAsServiceGas } from "@typeberry/block";
 import { W_C } from "@typeberry/block/gp-constants.js";
 import { codec, Encoder } from "@typeberry/codec";
-import type { ChainSpec } from "@typeberry/config";
+import type { ChainSpec, PvmBackend } from "@typeberry/config";
 import type { Blake2b } from "@typeberry/hash";
 import type { PendingTransfer } from "@typeberry/jam-host-calls/externalities/pending-transfer.js";
 import {
@@ -10,7 +10,7 @@ import {
 } from "@typeberry/jam-host-calls/externalities/state-update.js";
 import { Logger } from "@typeberry/logger";
 import { sumU64, tryAsU32 } from "@typeberry/numbers";
-import { tryAsGas } from "@typeberry/pvm-interpreter";
+import { tryAsGas } from "@typeberry/pvm-interface";
 import { ServiceAccountInfo, type ServicesUpdate, type State } from "@typeberry/state";
 import { check, Result } from "@typeberry/utils";
 import { AccumulateExternalities } from "../externalities/accumulate-externalities.js";
@@ -54,6 +54,7 @@ export class DeferredTransfers {
     public readonly chainSpec: ChainSpec,
     public readonly blake2b: Blake2b,
     private readonly state: DeferredTransfersState,
+    private readonly pvm: PvmBackend,
   ) {}
 
   async transition({
@@ -120,7 +121,12 @@ export class DeferredTransfers {
           logger.trace`Skipping ON_TRANSFER execution for service ${serviceId} because code is too long`;
         }
       } else {
-        const executor = PvmExecutor.createOnTransferExecutor(serviceId, code, { partialState, fetchExternalities });
+        const executor = await PvmExecutor.createOnTransferExecutor(
+          serviceId,
+          code,
+          { partialState, fetchExternalities },
+          this.pvm,
+        );
         const args = Encoder.encodeObject(
           ARGS_CODEC,
           { timeslot, serviceId, transfersLength: tryAsU32(transfers.length) },
diff --git a/packages/jam/transition/accumulate/pvm-executor.ts b/packages/jam/transition/accumulate/pvm-executor.ts
index 0c4fa1430..4c78780b8 100644
--- a/packages/jam/transition/accumulate/pvm-executor.ts
+++ b/packages/jam/transition/accumulate/pvm-executor.ts
@@ -1,6 +1,6 @@
 import type { ServiceId } from "@typeberry/block";
 import type { BytesBlob } from "@typeberry/bytes";
-import type { ChainSpec } from "@typeberry/config";
+import type { ChainSpec, PvmBackend } from "@typeberry/config";
 import { Assign } from "@typeberry/jam-host-calls/accumulate/assign.js";
 import { Bless } from "@typeberry/jam-host-calls/accumulate/bless.js";
 import { Checkpoint } from "@typeberry/jam-host-calls/accumulate/checkpoint.js";
@@ -28,8 +28,7 @@ import { Missing } from "@typeberry/jam-host-calls/missing.js";
 import { type AccountsRead, Read } from "@typeberry/jam-host-calls/read.js";
 import { type AccountsWrite, Write } from "@typeberry/jam-host-calls/write.js";
 import { type HostCallHandler, HostCalls, PvmHostCallExtension, PvmInstanceManager } from "@typeberry/pvm-host-calls";
-import type { Gas } from "@typeberry/pvm-interpreter";
-import { Program } from "@typeberry/pvm-program";
+import type { Gas } from "@typeberry/pvm-interface";
 
 const ACCUMULATE_HOST_CALL_CLASSES = [
   Bless,
@@ -71,18 +70,22 @@ namespace entrypoint {
 export class PvmExecutor {
   private readonly pvm: PvmHostCallExtension;
   private hostCalls: HostCalls;
-  private pvmInstanceManager = new PvmInstanceManager(4);
 
   private constructor(
     private serviceCode: BytesBlob,
     hostCallHandlers: HostCallHandler[],
     private entrypoint: ProgramCounter,
+    pvmInstanceManager: PvmInstanceManager,
   ) {
     this.hostCalls = new HostCalls({
       missing: new Missing(),
       handlers: hostCallHandlers,
     });
-    this.pvm = new PvmHostCallExtension(this.pvmInstanceManager, this.hostCalls);
+    this.pvm = new PvmHostCallExtension(pvmInstanceManager, this.hostCalls);
+  }
+
+  private static async prepareBackend(pvm: PvmBackend) {
+    return PvmInstanceManager.new(pvm);
   }
 
   /** Prepare accumulation host call handlers */
@@ -130,29 +133,31 @@ export class PvmExecutor {
    * @returns `ReturnValue` object that can be a status or memory slice
    */
   async run(args: BytesBlob, gas: Gas) {
-    const program = Program.fromSpi(this.serviceCode.raw, args.raw, true);
-
-    return this.pvm.runProgram(program.code, Number(this.entrypoint), gas, program.registers, program.memory);
+    return this.pvm.runProgram(this.serviceCode.raw, args.raw, Number(this.entrypoint), gas);
   }
 
   /** A utility function that can be used to prepare accumulate executor */
-  static createAccumulateExecutor(
+  static async createAccumulateExecutor(
     serviceId: ServiceId,
     serviceCode: BytesBlob,
     externalities: AccumulateHostCallExternalities,
     chainSpec: ChainSpec,
+    pvm: PvmBackend,
   ) {
     const hostCallHandlers = PvmExecutor.prepareAccumulateHostCalls(serviceId, externalities, chainSpec);
-    return new PvmExecutor(serviceCode, hostCallHandlers, entrypoint.ACCUMULATE);
+    const instances = await PvmExecutor.prepareBackend(pvm);
+    return new PvmExecutor(serviceCode, hostCallHandlers, entrypoint.ACCUMULATE, instances);
   }
 
   /** A utility function that can be used to prepare on transfer executor */
-  static createOnTransferExecutor(
+  static async createOnTransferExecutor(
     serviceId: ServiceId,
     serviceCode: BytesBlob,
     externalities: OnTransferHostCallExternalities,
+    pvm: PvmBackend,
   ) {
     const hostCallHandlers = PvmExecutor.prepareOnTransferHostCalls(serviceId, externalities);
-    return new PvmExecutor(serviceCode, hostCallHandlers, entrypoint.ON_TRANSFER);
+    const instances = await PvmExecutor.prepareBackend(pvm);
+    return new PvmExecutor(serviceCode, hostCallHandlers, entrypoint.ON_TRANSFER, instances);
   }
 }
diff --git a/packages/jam/transition/chain-stf.ts b/packages/jam/transition/chain-stf.ts
index 8577b0449..9f4067934 100644
--- a/packages/jam/transition/chain-stf.ts
+++ b/packages/jam/transition/chain-stf.ts
@@ -2,7 +2,7 @@ import type { BlockView, CoreIndex, EntropyHash, HeaderHash, ServiceId, TimeSlot
 import type { GuaranteesExtrinsicView } from "@typeberry/block/guarantees.js";
 import type { AuthorizerHash } from "@typeberry/block/refine-context.js";
 import { asKnownSize, HashSet } from "@typeberry/collections";
-import type { ChainSpec } from "@typeberry/config";
+import { type ChainSpec, PvmBackend } from "@typeberry/config";
 import type { Ed25519Key } from "@typeberry/crypto";
 import type { BlocksDb } from "@typeberry/database";
 import { Disputes, type DisputesStateUpdate } from "@typeberry/disputes";
@@ -145,6 +145,7 @@ export class OnChain {
     public readonly state: State & WithStateView,
     blocks: BlocksDb,
     public readonly hasher: TransitionHasher,
+    pvm: PvmBackend = PvmBackend.BuiltIn,
   ) {
     const bandersnatch = BandernsatchWasm.new();
     this.statistics = new Statistics(chainSpec, state);
@@ -158,9 +159,9 @@ export class OnChain {
 
     this.reports = new Reports(chainSpec, hasher.blake2b, state, new DbHeaderChain(blocks));
     this.assurances = new Assurances(chainSpec, state, hasher.blake2b);
-    this.accumulate = new Accumulate(chainSpec, hasher.blake2b, state);
+    this.accumulate = new Accumulate(chainSpec, hasher.blake2b, state, pvm);
     this.accumulateOutput = new AccumulateOutput();
-    this.deferredTransfers = new DeferredTransfers(chainSpec, hasher.blake2b, state);
+    this.deferredTransfers = new DeferredTransfers(chainSpec, hasher.blake2b, state, pvm);
     this.preimages = new Preimages(state, hasher.blake2b);
 
     this.authorization = new Authorization(chainSpec, state);
diff --git a/packages/jam/transition/package.json b/packages/jam/transition/package.json
index 7824b0a71..0d3bfd81c 100644
--- a/packages/jam/transition/package.json
+++ b/packages/jam/transition/package.json
@@ -13,11 +13,12 @@
     "@typeberry/database": "*",
     "@typeberry/disputes": "*",
     "@typeberry/hash": "*",
+    "@typeberry/jam-host-calls": "*",
     "@typeberry/logger": "*",
     "@typeberry/mmr": "*",
     "@typeberry/numbers": "*",
-    "@typeberry/jam-host-calls": "*",
     "@typeberry/pvm-host-calls": "*",
+    "@typeberry/pvm-interface": "*",
     "@typeberry/pvm-interpreter": "*",
     "@typeberry/pvm-program": "*",
     "@typeberry/safrole": "*",
diff --git a/packages/workers/importer/importer.ts b/packages/workers/importer/importer.ts
index afdd9bfba..49a4546ee 100644
--- a/packages/workers/importer/importer.ts
+++ b/packages/workers/importer/importer.ts
@@ -1,5 +1,5 @@
 import { type BlockView, type HeaderHash, type HeaderView, type StateRootHash, tryAsTimeSlot } from "@typeberry/block";
-import type { ChainSpec } from "@typeberry/config";
+import type { ChainSpec, PvmBackend } from "@typeberry/config";
 import type { BlocksDb, LeafDb, StatesDb, StateUpdateError } from "@typeberry/database";
 import { WithHash } from "@typeberry/hash";
 import type { Logger } from "@typeberry/logger";
@@ -36,6 +36,7 @@ export class Importer {
 
   constructor(
     spec: ChainSpec,
+    pvm: PvmBackend,
     private readonly hasher: TransitionHasher,
     private readonly logger: Logger,
     private readonly blocks: BlocksDb,
@@ -48,7 +49,7 @@ export class Importer {
     }
 
     this.verifier = new BlockVerifier(hasher, blocks);
-    this.stf = new OnChain(spec, state, blocks, hasher);
+    this.stf = new OnChain(spec, state, blocks, hasher, pvm);
     this.state = state;
     this.currentHash = currentBestHeaderHash;
     this.prepareForNextEpoch();
diff --git a/packages/workers/importer/main.ts b/packages/workers/importer/main.ts
index 8e0de4921..adccaf2c5 100644
--- a/packages/workers/importer/main.ts
+++ b/packages/workers/importer/main.ts
@@ -18,11 +18,12 @@ type Config = WorkerConfig<ImporterConfig, BlocksDb, StatesDb<SerializedState<Le
 export async function createImporter(config: Config) {
   const chainSpec = config.chainSpec;
   const db = config.openDatabase({ readonly: false });
+  const interpreter = config.workerParams.pvm;
   const blocks = db.getBlocksDb();
   const states = db.getStatesDb();
 
   const hasher = new TransitionHasher(chainSpec, await keccakHasher, await blake2b);
-  const importer = new Importer(chainSpec, hasher, logger, blocks, states);
+  const importer = new Importer(chainSpec, interpreter, hasher, logger, blocks, states);
 
   return {
     importer,
diff --git a/packages/workers/importer/package.json b/packages/workers/importer/package.json
index f203aa62f..2786b4f01 100644
--- a/packages/workers/importer/package.json
+++ b/packages/workers/importer/package.json
@@ -9,6 +9,7 @@
     "@typeberry/codec": "*",
     "@typeberry/collections": "*",
     "@typeberry/config": "*",
+    "@typeberry/config-node": "*",
     "@typeberry/crypto": "*",
     "@typeberry/database": "*",
     "@typeberry/hash": "*",
diff --git a/packages/workers/importer/protocol.ts b/packages/workers/importer/protocol.ts
index f39f567d0..4f774a0f1 100644
--- a/packages/workers/importer/protocol.ts
+++ b/packages/workers/importer/protocol.ts
@@ -1,8 +1,9 @@
 import { Block, type HeaderHash, headerViewWithHashCodec, type StateRootHash } from "@typeberry/block";
 import { BytesBlob } from "@typeberry/bytes";
 import { type CodecRecord, codec } from "@typeberry/codec";
+import { PvmBackend } from "@typeberry/config";
 import { HASH_SIZE, type OpaqueHash } from "@typeberry/hash";
-import { tryAsU32 } from "@typeberry/numbers";
+import { tryAsU8, tryAsU32 } from "@typeberry/numbers";
 import { StateEntries } from "@typeberry/state-merkleization";
 import { Result } from "@typeberry/utils";
 import { type Api, createProtocol, type Internal } from "@typeberry/workers-api";
@@ -80,11 +81,26 @@ export type ImporterApi = Api<typeof protocol>;
 export class ImporterConfig {
   static Codec = codec.Class(ImporterConfig, {
     omitSealVerification: codec.bool,
+    pvm: codec.u8.convert(
+      (i) => tryAsU8(i),
+      (o) => {
+        if (o === PvmBackend.BuiltIn) {
+          return PvmBackend.BuiltIn;
+        }
+        if (o === PvmBackend.Ananas) {
+          return PvmBackend.Ananas;
+        }
+        throw new Error(`Invalid PvmBackend: ${o}`);
+      },
+    ),
   });
 
-  static create({ omitSealVerification }: CodecRecord<ImporterConfig>) {
-    return new ImporterConfig(omitSealVerification);
+  static create({ omitSealVerification, pvm }: CodecRecord<ImporterConfig>) {
+    return new ImporterConfig(omitSealVerification, pvm);
   }
 
-  private constructor(public readonly omitSealVerification: boolean) {}
+  private constructor(
+    public readonly omitSealVerification: boolean,
+    public readonly pvm: PvmBackend,
+  ) {}
 }