Hardhat

To verify your Hardhat contracts, you can use Hardhat's Etherscan plugin to verify contracts on BlockScout.

note

Note that this is included as part of the hardhat-toolbox plugin.

These steps assume you stored your secret keys in a .env file, which you can read more about here.

Download the plugin

If you aren't already using @nomicfoundation/hardhat-toolbox, download the etherscan plugin:

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

And add the plugin to the top of your hardhat.config.js file:

require("@nomiclabs/hardhat-etherscan");

Add your Etherscan API Key

We'll be using a .env file to store our sensitive information:

npm i -D dotenv

Next, you'll need to get an Etherscan key by creating an account at https://etherscan.io/. Grab your key, and add it to the .env file:

PRIVATE_KEY=YOUR_PRIVATE_KEY_HERE
ETHERSCAN_API_KEY=YOUR_API_KEY_HERE

Then, add the key to your hardhat.config.js as follows:

require("@nomicfoundation/hardhat-toolbox");
require("dotenv").config();
const { PRIVATE_KEY, ETHERSCAN_API_KEY } = process.env;

module.exports = {
  solidity: "0.8.17",
  networks: {
    linea: {
      url: `https://rpc.goerli.linea.build/`,
      accounts: [PRIVATE_KEY],
    },
  },
  etherscan: {
    apiKey: linea,
  },
};

Add the custom chain

Because Linea is not supported by the network yet, we'll have to add a custom chain like so:

etherscan: {
  apiKey: {
    linea: ETHERSCAN_API_KEY
  },
  customChains: [
    {
      network: "linea",
      chainId: 59140,
      urls: {
        apiURL: "https://explorer.goerli.linea.build/api",
        browserURL: "https://explorer.goerli.linea.build/"
      }
    }
  ]
}

note

The Etherscan apiKey and network name for your custom chain must match the network name under networks in your hardhat.config.js.

Verify the smart contract

To verify your contract, run the following command:

npx hardhat verify --network linea <DEPLOYED_CONTRACT_ADDRESS>

Don't worry if your result looks like this:

Successfully submitted source code for contract
contracts/Token.sol:Token at 0xF0d4039a96b01F3767010dEf837EfB3CCfe54675
for verification on the block explorer. Waiting for verification result...

Error in plugin @nomiclabs/hardhat-etherscan: The API responded with an unexpected message.
Contract verification may have succeeded and should be checked manually.
Message: Unknown UID

For more info run Hardhat with --show-stack-traces

You can check that it was verified correctly by navigating to the block explorer and pasting in the deployed contract address.

info

Learn more about different configurations for verifying your smart contracts.