👷 Hardhat

Hardhat is a development environment for Ethereum and EVM chains: compile Solidity, run tests, and run scripts (deploy, interact) from the command line. It’s the standard choice for serious EVM development.

🎯 Why Hardhat

Local network — Built-in Hardhat Network for fast tests and debugging
TypeScript/JavaScript — Write tests and scripts in JS/TS with Ethers or Viem
Plugins — Hardhat Toolbox , Etherscan verification , deployment, coverage
Documentation — hardhat.org and Hardhat docs

🚀 Quick Start


mkdir my-project && cd my-project
npm init -y
npm install --save-dev hardhat @nomicfoundation/hardhat-toolbox
npx hardhat init

Choose Create a JavaScript project (or TypeScript). Then:


npx hardhat compile
npx hardhat test

📁 Project Layout


contracts/     # Solidity sources
scripts/       # Deploy and utility scripts
test/          # Tests (e.g. *.js / *.ts)
hardhat.config.js

⚙️ Config Example (Multiple Networks)


// hardhat.config.js
require("@nomicfoundation/hardhat-toolbox");
require("dotenv").config();
 
module.exports = {
  solidity: "0.8.24",
  networks: {
    hardhat: {
      chainId: 1337,
    },
    sepolia: {
      url: process.env.SEPOLIA_RPC_URL,
      accounts: process.env.PRIVATE_KEY ? [process.env.PRIVATE_KEY] : [],
    },
    mainnet: {
      url: process.env.MAINNET_RPC_URL,
      accounts: process.env.PRIVATE_KEY ? [process.env.PRIVATE_KEY] : [],
    },
  },
  etherscan: {
    apiKey: {
      sepolia: process.env.ETHERSCAN_API_KEY,
      mainnet: process.env.ETHERSCAN_API_KEY,
    },
  },
};

Secrets go in .env; see Environment Variables.

📝 Deploy Script Example


// scripts/deploy.js
const hre = require("hardhat");
 
async function main() {
  const [deployer] = await hre.ethers.getSigners();
  console.log("Deploying with", deployer.address);
 
  const MyContract = await hre.ethers.getContractFactory("MyContract");
  const contract = await MyContract.deploy(/* constructor args */);
  await contract.waitForDeployment();
 
  const address = await contract.getAddress();
  console.log("Deployed to", address);
}
 
main()
  .then(() => process.exit(0))
  .catch((err) => {
    console.error(err);
    process.exit(1);
  });

Run:


npx hardhat run scripts/deploy.js --network sepolia

🧪 Test Example


// test/MyContract.js
const { expect } = require("chai");
const hre = require("hardhat");
 
describe("MyContract", function () {
  it("should do something", async function () {
    const [owner] = await hre.ethers.getSigners();
    const MyContract = await hre.ethers.getContractFactory("MyContract");
    const contract = await MyContract.deploy();
    await contract.waitForDeployment();
 
    await expect(contract.someFunction()).to.not.be.reverted;
  });
});

🔗 Resources

Hardhat official site
Hardhat documentation
Hardhat Toolbox
TUM Hardhat & Web3 Dev Setup — Full workshop flow