Error with Hardhat Clean: Cannot find module '@nomicfoundation/hardhat-etherscan'

I'm encountering an error when trying to clean my Hardhat project workspace:

npx hardhat clean
An unexpected error occurred: Error: Cannot find module '@nomicfoundation/hardhat-etherscan'

What I've tried:

• Installing the missing package:

  npm install --save-dev @nomiclabs/hardhat-etherscan
  

• Deleting node_modules and package-lock.json, then running:

  npm install
  

• Checking hardhat.config.js for incorrect imports

My hardhat.config.js:

require("@nomicfoundation/hardhat-toolbox");
require("@nomicfoundation/hardhat-etherscan");
require("dotenv").config();

const SEPOLIA_RPC_URL = process.env.SEPOLIA_RPC_URL;
const PRIVATE_KEY = process.env.PRIVATE_KEY;
const ETHERSCAN_API_KEY = process.env.ETHERSCAN_API_KEY;

/** @type import('hardhat/config').HardhatUserConfig */
module.exports = {
  defaultNetwork: "hardhat",
  networks: {
    sepolia: {
      url: SEPOLIA_RPC_URL,
      accounts: [PRIVATE_KEY],
      chainId: 11155111,
    },
  },
  etherscan: {
    apiKey: ETHERSCAN_API_KEY,
  },
  solidity: "0.8.9",
};

Environment:

• Node.js version: v22.13.1
• Hardhat version: 2.22.19
• OS: Windows

What could be the possible reason for this error, and how can I fix it?

Error with Hardhat Clean: Cannot find module '@nomicfoundation/hardhat-etherscan'

I'm encountering an error when trying to clean my Hardhat project workspace:

npx hardhat clean
An unexpected error occurred: Error: Cannot find module '@nomicfoundation/hardhat-etherscan'

What I've tried:

• Installing the missing package:

  npm install --save-dev @nomiclabs/hardhat-etherscan
  

• Deleting node_modules and package-lock.json, then running:

  npm install
  

• Checking hardhat.config.js for incorrect imports

My hardhat.config.js:

require("@nomicfoundation/hardhat-toolbox");
require("@nomicfoundation/hardhat-etherscan");
require("dotenv").config();

const SEPOLIA_RPC_URL = process.env.SEPOLIA_RPC_URL;
const PRIVATE_KEY = process.env.PRIVATE_KEY;
const ETHERSCAN_API_KEY = process.env.ETHERSCAN_API_KEY;

/** @type import('hardhat/config').HardhatUserConfig */
module.exports = {
  defaultNetwork: "hardhat",
  networks: {
    sepolia: {
      url: SEPOLIA_RPC_URL,
      accounts: [PRIVATE_KEY],
      chainId: 11155111,
    },
  },
  etherscan: {
    apiKey: ETHERSCAN_API_KEY,
  },
  solidity: "0.8.9",
};

Environment:

• Node.js version: v22.13.1
• Hardhat version: 2.22.19
• OS: Windows

What could be the possible reason for this error, and how can I fix it?

• node.js
• blockchain
• solidity
• hardhat
• etherscan

1 Answer 1

Your code tries to import @nomicfoundation/hardhat-etherscan on line 2. But the expected package name is @nomiclabs/hardhat-etherscan (different scope name, before the slash symbol).

updated hardhat-config.js:

// instead of require("@nomicfoundation/hardhat-etherscan");
require("@nomiclabs/hardhat-etherscan");

Also note that the @nomiclabs/hardhat-etherscan package is deprecated in favor of @nomicfoundation/hardhat-verify (source). So you might want to use this one instead:

npm install --save-dev @nomicfoundation/hardhat-verify

updated hardhat-config.js:

// instead of require("@nomicfoundation/hardhat-etherscan");
require("@nomicfoundation/hardhat-verify");