Solidity Smart Contract Development

Decision Points

Toolchain: Foundry (preferred) for new projects. Hardhat for existing JS/TS ecosystems.

Base contracts: Always start with OpenZeppelin when pattern exists (tokens, access control, upgrades).

Solidity version: Use ^0.8.20 minimum. Named imports: import {ERC20} from "...";

Security-First Mindset

CEI Pattern (Checks-Effects-Interactions):

1. Checks - Validate all conditions and inputs first
2. Effects - Update contract state
3. Interactions - External calls LAST

This order prevents reentrancy. If external call happens before state update, attacker can re-enter and exploit stale state. Use ReentrancyGuard as additional protection.