Letters to the Future

An on-chain message board on Base where anyone can write a letter, lock it as a time capsule, and mint it as a fully on-chain NFT.

Live Demo

https://letters-to-the-future.vercel.app/

Also available as a Farcaster / Base Mini App.

Contracts

All contracts are deployed on Base Mainnet (chainId 8453).

Contract	Address	Role
LettersToTheFutureV2	0x8FeF460431Ae853fA74fA53f9B005de5cb9Df0EF	Active message board with time capsule support
LetterNFT	0x3C01937B5d7a800C960170F9AF47aBB4237CB6C6	ERC-721 for minting letters as on-chain SVG NFTs
LettersToTheFuture (V1)	0x526A3e3ACe6f5eF40Ec8ddB8E87995f9A8271000	Legacy contract, still read for older letters

Features

• Write letters up to 280 characters, stored permanently on-chain
• Time capsule mode: set an unlock date and the UI keeps the letter sealed until then
• Mint any letter as an ERC-721 NFT with fully on-chain SVG artwork (0.001 ETH mint fee)
• Anonymous display mode that hides your address in the UI
• Runs as a Farcaster / Base Mini App with wallet connect via any EIP-1193 wallet

Tech Stack

• Solidity ^0.8.20 with Foundry (forge, cast, anvil) for build, test, and deploy
• OpenZeppelin Contracts (ERC-721, Base64, Strings)
• Vanilla HTML/CSS/JS frontend, no framework, no build step
• ethers.js v6
• Farcaster Mini App SDK
• Base Mainnet

Getting Started

Prerequisites

• Foundry

Clone and install

git clone https://github.com/memosr/letters-to-the-future.git
cd letters-to-the-future
forge install

Build and test

forge build
forge test

Environment

Create a .env file in the project root:

PRIVATE_KEY=your_private_key
BASESCAN_API_KEY=your_basescan_api_key

Warning: Never commit your .env file or share your private key. Use a dedicated deployer wallet.

Deploy

# Message board (V2)
forge script script/DeployV2.s.sol --rpc-url base --broadcast --verify -vvvv

# Letter NFT
forge script script/DeployLetterNFT.s.sol --rpc-url base --broadcast --verify -vvvv

Run the frontend

The frontend is a single static page. Serve the docs/ folder with any static server:

cd docs
python3 -m http.server 8000

Then open http://localhost:8000.

License

MIT