Foundry is a robust, fast, and modular toolkit for Ethereum application development, written in Rust. It comprises several components: Forge, an Ethereum testing framework, Cast, a versatile tool for interacting with EVM smart contracts, sending transactions, and retrieving chain data; Anvil, a local Ethereum node akin to Ganache and Hardhat Network; and Chisel, a Solidity REPL. Foundry is designed to be highly configurable, it supports fast and flexible compilation pipelines, automatic Solidity compiler version detection and installation and caching and parallel compilation, among other features. Tests can be written in Solidity. It offers fast fuzz testing with shrinking of inputs and printing of counter-examples. Foundry also provides fast remote RPC forking mode