Permit2 Vault Adapter — Vault Forge

Description

Stateless adapter enabling one-transaction ERC-4626 vault deposits via Uniswap Permit2. Eliminates the separate approve transaction. Supports single and batch deposits across multiple vaults.

Details

Category: contracts
Files: 8
Chains: Ethereum, Arbitrum, Base, Optimism

Solidity ^0.8.24 OpenZeppelin v5 Permit2 Foundry Ethereum Arbitrum Base Optimism

Single-tx deposits (no separate approve)
Batch deposits across multiple vaults
Slippage protection (minSharesOut)
Completely stateless — no funds held
Works with any ERC-4626 vault
Canonical Permit2 integration
Full NatSpec + security notes
Comprehensive test suite with mocks

permit2-vault-adapter.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

/// @title Permit2 Vault Adapter
/// @notice One-tx deposit flows using Permit2 for non-EIP-2612 tokens.
contract Permit2VaultAdapter {
    address public immutable owner;
    uint256 public constant VERSION = 1;

    event Initialized(address indexed deployer);

    constructor() {
        owner = msg.sender;
        emit Initialized(msg.sender);
    }

    // ... full implementation in purchased package
}