> For the complete documentation index, see [llms.txt](https://docs.blastchain.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.blastchain.org/verifying-smart-contracts.md).

# Verifying Smart Contracts

### Using Developer Tools <a href="#using-developer-tools" id="using-developer-tools"></a>

Most smart contract tooling has plugins for verifying your contracts easily on Blast chain explorer.

Blast Chain Explorer API:  [https://blastchain.org/api](https://blastchain.org/api-docs)

### Hardhat <a href="#hardhat" id="hardhat"></a>

Modify `hardhat.config.ts` to point to Blast Chain’s RPC and block explorer API.

For example, the config for Blast Chain will look like this:

```javascript
...

const config: HardhatUserConfig = {
  ...
  networks: {
    blastChain: {
      url: 'https://zkevmrpc.blastchain.org' || '',
      accounts:
        process.env.PRIVATE_KEY !== undefined ? [process.env.PRIVATE_KEY] : [],
    },
  },
  etherscan: {
    apiKey: {
      blastChain: <YOUR API KEY>,
    },
    customChains: [
      {
        network: 'blastChain',
        chainId: 238,
        urls: {
          apiURL: 'https://blastchain.org/api',
          browserURL: 'https://blastchain.org/',
        },
      },
    ],
  },
}

...
```

Now you can verify the smart contract by running the following command.

```
npx hardhat verify --network blastChain <contract address> <space separated constructor parameters>

```

For example, this is how a smart contract that receives two uint parameters in the constructor should look:

```
npx hardhat verify --network blastChain 0xD9885478bd717189cC3Fbe7B9020F27fae7Ac76F 123 456
```

{% hint style="warning" %}
You may receive an error stating `etherscan.apiKey.trim is not a function`. If so, you need to update `@nomiclabs/hardhat-etherscan` to be able to support custom chains. Try running `npm update @nomiclabs/hardhat-etherscan`
{% endhint %}