Foundry

Foundry is a blazing fast, portable, and modular toolkit for Ethereum application development written entirely in Rust. Developed by Paradigm (a leading crypto investment and research firm) and released in 2021, Foundry has quickly become the preferred development environment for Solidity smart contracts, replacing Hardhat and Truffle for many developers. As of 2026, it has over 8,500 stars. The toolkit consists of four core tools: Forge (the Ethereum testing framework, enabling writing tests in Solidity with cheatcodes for manipulating state like vm.warp, vm.prank, vm.roll, fuzz testing with automatic input generation, invariant testing for property-based testing, gas reporting per function, coverage analysis, and deployment with verification to Etherscan and Sourcify), Anvil (a local Ethereum development node similar to Ganache/Hardhat Network, supporting mainnet forking via archive RPC endpoints, JSON-RPC API compatibility, mining modes: auto, interval, and none, custom genesis configuration, and account impersonation), Cast (a command-line Swiss Army knife for interacting with Ethereum nodes, enabling RPC calls, transaction decoding, ABI encoding and decoding, keccak256 hashing, signature recovery, contract reading and writing, and chain state inspection), and Chisel (a Solidity REPL for rapid prototyping and debugging). Foundry projects are configured via foundry.toml with configurable Solidity compiler versions, optimizer settings, remappings, and test profiles.