🏦 ERC-8416: Epoch-Based Fixed-Rate Vault

Reference implementation of ERC-8416: an ERC-4626 vault that pays a fixed rate over scheduled epochs, with deposits that settle right away and redemptions that go through a request queue (ERC-7540).

⚙️ How it works

This is one example schedule. Each epoch sets its own windows, so they can be longer, shorter, overlap, or leave gaps.

• Entry window: deposit / mint are open, up to the epoch's deposit cap.
• Accrual interval: totalAssets grows at the epoch's fixed APR, so the share price only rises here. Interest compounds from one epoch to the next.
• Exit window: holders call requestRedeem, the owner calls fulfillRedeem, then holders redeem / withdraw.
• Limbo: time between epochs, when deposits and redemption requests are both closed.
• Strategy: deposited funds go to an IFixedRateStrategy, which must return principal plus interest.
• Termination: after the last epoch ends, the owner pulls all funds back and the exit window stays open forever.

🗂️ Layout

File	What
src/IERC8416.sol	ERC-8416 interface
src/IERC7540.sol	Async-redeem and operator interfaces (ERC-7540 / ERC-7575)
src/IFixedRateStrategy.sol	Strategy hook
src/FixedRateVault.sol	Reference vault
test/	Foundry unit and fuzz tests

🚀 Quickstart

You need Foundry and Node.js. Dependencies are installed with npm (no git submodules).

npm install        # OpenZeppelin + forge-std
npm run build      # compile
npm test           # run tests
npm run coverage   # coverage summary
npm run fmt        # format with Prettier

⚠️ Disclaimer

This is a reference implementation for discussing the standard. It has not been audited. Do not use it in production.

📜 License

CC0-1.0