diff --git a/packages/browser/src/client/tester/tester-utils.ts b/packages/browser/src/client/tester/tester-utils.ts
index b53794ae5799..5578a8f0c55b 100644
--- a/packages/browser/src/client/tester/tester-utils.ts
+++ b/packages/browser/src/client/tester/tester-utils.ts
@@ -133,7 +133,6 @@ export class CommandsManager {
     const rpc = state.rpc as any as BrowserRPC
     const { sessionId, traces } = getBrowserState()
     const filepath = state.filepath || state.current?.file?.filepath
-    args = args.filter(arg => arg !== undefined) // remove optional fields
 
     const actionTraceGroupName = ACTION_TRACE_COMMANDS.has(command)
       ? `vitest:${command.slice('__vitest_'.length)}`
diff --git a/packages/browser/src/node/rpc.ts b/packages/browser/src/node/rpc.ts
index c5ee14b2b45e..30aa998a5adf 100644
--- a/packages/browser/src/node/rpc.ts
+++ b/packages/browser/src/node/rpc.ts
@@ -339,6 +339,7 @@ export function setupBrowserRpc(globalServer: ParentBrowserProject, defaultMocke
           }
         },
         async triggerCommand(sessionId, command, testPath, payload) {
+          payload = payload.map(value => value === null ? undefined : value)
           debug?.('[%s] Triggering command "%s"', sessionId, command)
           const provider = project.browser!.provider
           if (!provider) {
diff --git a/test/browser/test/commands.test.ts b/test/browser/test/commands.test.ts
index 0661dd513d8a..1e7b5ade6ccb 100644
--- a/test/browser/test/commands.test.ts
+++ b/test/browser/test/commands.test.ts
@@ -45,19 +45,39 @@ it('can manipulate files', async () => {
 })
 
 it('can run custom commands', async () => {
-  const result = await myCustomCommand('arg1', 'arg2')
-  expect(result).toEqual({
-    testPath: expect.stringMatching('test/browser/test/commands.test.ts'),
-    arg1: 'arg1',
-    arg2: 'arg2',
-  })
+  {
+    const result = await myCustomCommand('arg1', 'arg2')
+    expect(result).toEqual({
+      testPath: expect.stringMatching('test/browser/test/commands.test.ts'),
+      arg1: 'arg1',
+      arg2: 'arg2',
+    })
+  }
+
+  {
+    const result = await myCustomCommand(undefined, 'arg2')
+    expect(result).toEqual({
+      testPath: expect.stringMatching('test/browser/test/commands.test.ts'),
+      arg1: undefined,
+      arg2: 'arg2',
+    })
+  }
+
+  {
+    const result = await myCustomCommand(null, 'arg2')
+    expect(result).toEqual({
+      testPath: expect.stringMatching('test/browser/test/commands.test.ts'),
+      arg1: null,
+      arg2: 'arg2',
+    })
+  }
 })
 
 declare module 'vitest/browser' {
   interface BrowserCommands {
-    myCustomCommand: (arg1: string, arg2: string) => Promise<{
+    myCustomCommand: (arg1: string | undefined | null, arg2: string) => Promise<{
       testPath: string
-      arg1: string
+      arg1: string | undefined | null
       arg2: string
     }>