Web3 Docs

Up-to-date documentation and code patterns for Solidity, Foundry, Hardhat, Viem, Wagmi, ethers.js, and OpenZeppelin. Use when writing smart contracts, debugging Solidity errors, setting up a Foundry project, writing Viem/Wagmi frontend code, or asking about ERC standards, gas optimization, upgradeable contracts, or any EVM development task. Triggers on: Solidity, Foundry, Hardhat, Viem, Wagmi, ethers.js, OpenZeppelin, ERC-20, ERC-721, ERC-4626, UUPS, proxy patterns, ABI, calldata, smart contract, deploy, cast, forge, anvil, or any EVM/blockchain development question.

Current patterns and references for EVM development. Covers the full stack: contracts → testing → deployment → frontend integration.

Stack Coverage

Layer	Tool	Reference
Contracts	Solidity 0.8.x	references/solidity.md
Framework	Foundry (forge/cast/anvil)	references/foundry.md
Framework (alt)	Hardhat	references/hardhat.md
Standards	OpenZeppelin 5.x	references/openzeppelin.md
Standards	ERC-4626 (tokenized vaults)	references/erc4626.md
Frontend (low-level)	Viem 2.x	references/viem.md
Frontend (React)	Wagmi 2.x	references/wagmi.md
Frontend (legacy)	ethers.js 6.x	references/ethers.md

Quick Lookup

Starting a new Foundry project: See references/foundry.md → Project Setup

Starting a Hardhat project: See references/hardhat.md → Installation

Writing an ERC-20: See references/openzeppelin.md → ERC-20

Building a yield vault (ERC-4626): See references/erc4626.md → OpenZeppelin Implementation

First depositor attack on vaults: See references/erc4626.md → First Depositor Attack

Connecting a wallet in React: See references/wagmi.md → Quick Start

Reading contract state with Viem: See references/viem.md → Read Contracts

Common Solidity errors: See references/solidity.md → Error Reference

Deploying to Optimism/Base with Hardhat: See references/hardhat.md → hardhat.config.ts

Fetch Latest Docs

scripts/fetch-docs.js <topic> pulls live docs from official sources when the reference files may be stale.

node scripts/fetch-docs.js solidity      # Solidity docs
node scripts/fetch-docs.js foundry       # Foundry book
node scripts/fetch-docs.js viem          # Viem docs
node scripts/fetch-docs.js wagmi         # Wagmi docs
node scripts/fetch-docs.js openzeppelin  # OZ docs
node scripts/fetch-docs.js hardhat       # Hardhat docs
node scripts/fetch-docs.js erc4626       # ERC-4626 (OZ vault docs)

Gas Optimization Quick Rules

1. Use calldata instead of memory for read-only function params
2. Pack storage variables: multiple uint128 in one slot beats two separate uint256
3. unchecked blocks for arithmetic that can't overflow (saves ~30 gas/op)
4. immutable > constant > storage for values set once
5. Events are cheaper than storage for historical data
6. Batch operations: one tx touching N items beats N txs