Foundry

Foundry is the Ethereum dev toolkit that makes Hardhat feel slow. Tests run in Solidity (not JavaScript), execute 10-100x faster, and the built-in fuzz testing catches edge-case vulnerabilities that unit tests miss. Forge, Cast, Anvil, and Chisel give you testing, RPC interaction, local chains, and a REPL — all in one Rust-powered CLI.

If you're writing Solidity and care about test speed and security, Foundry is the move. Hardhat still powers 60% of projects with better JavaScript integration, TypeScript support, and a larger plugin ecosystem. Truffle is legacy — don't start new projects on it. Remix is the browser IDE for quick prototyping.

The catch: Foundry means Solidity-only testing. No JavaScript, no TypeScript. If your team writes frontend integration tests alongside contracts, you'll need both Foundry and Hardhat. The Solidity testing DSL (vm.prank, vm.deal) has its own learning curve. And Foundry's documentation, while improving, still assumes you already understand EVM internals deeply.