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# Hardhat

To verify your Hardhat contracts, use [Hardhat's Etherscan plugin](https://hardhat.org/hardhat-runner/plugins/nomiclabs-hardhat-etherscan) to verify contracts on Lineascan.

note

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 [in the Hardhat deployment instructions](/network/how-to/deploy-smart-contract/hardhat#deploy-the-contract).

## Download the plugin

If you aren't already using `@nomicfoundation/hardhat-toolbox`, you can use `@nomicfoundation/hardhat-verify` instead. Find the instructions on how to add it to your project [here](https://hardhat.org/hardhat-runner/plugins/nomicfoundation-hardhat-verify#installation).

## Add your Lineascan API Key

Obtain a Lineascan (Linea instance of Etherscan) key by creating an account at [https://lineascan.build/myapikey](https://lineascan.build/myapikey). Grab your key, and add it to the `.env` file:

```text
LINEASCAN_API_KEY=YOUR_API_KEY_HERE
```

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

```javascript
const { PRIVATE_KEY, LINEASCAN_API_KEY } = process.env;
```

## Add the custom chain

note

These instructions verify using the Linea instance of Etherscan, which currently doesn't support Yul. If you would like to verify using Blockscout, please use the [Blockscout API URL for the required network](/network/build/block-explorers).

First, we'll need to add a custom chain like so:

-   Mainnet
-   Testnet

```javascript
networks: {
  linea_mainnet: {
    ...
  }
},
etherscan: {
  apiKey: {
    linea_mainnet: LINEASCAN_API_KEY
  },
  customChains: [
    {
      network: "linea_mainnet",
      chainId: 59144,
      urls: {
        apiURL: "https://api.lineascan.build/api",
        browserURL: "https://lineascan.build/"
      }
    }
  ]
}
```

```javascript
networks: {
  linea_sepolia: {
    ...
  }
},
etherscan: {
  apiKey: {
    linea_sepolia: LINEASCAN_API_KEY
  },
  customChains: [
    {
      network: "linea_sepolia",
      chainId: 59141,
      urls: {
        apiURL: "https://api-sepolia.lineascan.build/api",
        browserURL: "https://sepolia.lineascan.build/address"
      }
    }
  ]
}
```

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:

-   Mainnet
-   Testnet

```bash
npx hardhat verify --network linea_mainnet <DEPLOYED_CONTRACT_ADDRESS> <CONTRACT_ARGUMENTS>
```

```bash
npx hardhat verify --network linea_sepolia <DEPLOYED_CONTRACT_ADDRESS> <CONTRACT_ARGUMENTS>
```

You should see something that looks a little like this if verifying on Linea Sepolia:

```bash
npx hardhat verify --network linea_sepolia 0x3Af089fee468eb7fcf750e929321b0D7f7845f5C "1893456000"

[INFO] Sourcify Verification Skipped: Sourcify verification is currently disabled. To enable it, add the following entry to your Hardhat configuration:

sourcify: {
  enabled: true
}

Or set 'enabled' to false to hide this message.

For more information, visit https://hardhat.org/hardhat-runner/plugins/nomicfoundation-hardhat-verify#verifying-on-sourcify
Successfully submitted source code for contract
contracts/Lock.sol:Lock at 0x3Af089fee468eb7fcf750e929321b0D7f7845f5C
for verification on the block explorer. Waiting for verification result...

Successfully verified contract Lock on the block explorer.
https://sepolia.lineascan.build/address/0x3Af089fee468eb7fcf750e929321b0D7f7845f5C#code
```

note

If you get an error saying that the address doesn't have bytecode, it probably means that Etherscan has not indexed your contract yet. In that case, wait for a while and then try again.

You can check that it was verified correctly by navigating to the [testnet block explorer](https://sepolia.lineascan.build/) or the [mainnet block explorer](https://lineascan.build/) and pasting in the deployed contract address.

info

[Learn more about different configurations for verifying your smart contracts](https://hardhat.org/hardhat-runner/docs/guides/verifying).