Blockchain Development

Foundry10.3k★

If you're building smart contracts on Ethereum (or any EVM chain) and want fast testing, deployment, and debugging — Foundry is a Rust-based toolkit that replaced Hardhat for a lot of Solidity developers. Write your tests in Solidity instead of JavaScript, and they run orders of magnitude faster. 10K stars, growing at +28/week, Apache 2.0. Four CLI tools: forge (build/test), cast (interact with contracts), anvil (local testnet), and chisel (Solidity REPL). The testing framework supports fuzz testing, invariant testing, and gas snapshots natively. Fully free. No paid tier, no hosted version. Install the CLI and go. The speed difference over Hardhat is not marginal — it's dramatic. Test suites that took minutes run in seconds. The Solidity-native testing means no context-switching between Solidity and JavaScript. Solo through large teams: free, no restrictions. The tooling is mature enough for production use at every scale. The catch: Foundry's Solidity-only testing means you lose access to Hardhat's JavaScript plugin ecosystem. If you need complex deployment scripts with off-chain logic, Hardhat's JavaScript flexibility is easier. The learning curve from Hardhat to Foundry is real — different testing patterns, different project structure. And if you're not in the EVM ecosystem, this is irrelevant.

Hardhat8.5k★

If you're building on Ethereum — smart contracts, DeFi protocols, NFT projects — Hardhat is the development environment that most Solidity developers reach for. Think of it as the Node.js of blockchain development: a local testing chain, a compiler, a debugger, and a deployment pipeline all in one. Everything is free and open source. No paid tier, no cloud service, no premium plugins. The core team (Nomic Foundation) is funded by the Ethereum Foundation, not by charging developers. MIT-like license on most components. There's nothing to host. Hardhat runs locally as a Node.js package. `npx hardhat` gets you a project scaffold, a local Ethereum network for testing, and a compilation pipeline. It integrates with ethers.js, Viem, and every major Ethereum library. Solo developers: this is your starting point for Solidity development. The local network and console.log in Solidity (yes, really) make debugging so much faster than the alternatives. Small teams: Hardhat's plugin system lets you add gas reporting, contract verification, and coverage analysis. Larger teams: the Hardhat Ignition deployment system handles multi-step contract deployments across networks. The catch: Hardhat is Ethereum-specific. If you're building on Solana, Cosmos, or other chains, this isn't for you. And compilation speed on large projects can be slow — Foundry (written in Rust) compiles significantly faster.