> ## Documentation Index
> Fetch the complete documentation index at: https://docs.celo.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Verify Smart Contract using Hardhat

Verifying a smart contract allows developers to review your code from within the CeloScan Block Explorer

<Tip>
  If you use [Celo Composer](https://github.com/celo-org/celo-composer) all the configuration is done for you out of the box, all you need is the CeloScan API keys!
</Tip>

## Prerequisites

Before the installation steps you need to have your hardhat project initialized using the command

```bash theme={null}
npx hardhat init
```

Make sure to have dependencies installed and the hardhat config file is importing `@nomicfoundation/hardhat-toolbox`

### Hardhat Configuration

Use environment variables for secrets. Install `dotenv`, create a `.env`, and load it at the top of `hardhat.config.js`.

```bash theme={null}
npm i -D dotenv
```

```js theme={null}
// hardhat.config.js
require("dotenv").config();
```

```bash theme={null}
# .env
PRIVATE_KEY=0xYOUR_PRIVATE_KEY
ETHERSCAN_API_KEY=your_celoscan_api_key
```

Then add the following configuration to the `config` object in `hardhat.config.js`.

```js theme={null}
    networks: {
        celoSepolia: {
            // can be replaced with the RPC url of your choice.
            url: "https://forno.celo-sepolia.celo-testnet.org/",
            accounts: [process.env.PRIVATE_KEY],
        },
        celo: {
            url: "https://forno.celo.org",
            accounts: [process.env.PRIVATE_KEY],
        }
    },
    etherscan: {
        apiKey: process.env.ETHERSCAN_API_KEY,
        customChains: [
            {
                network: "celoSepolia",
                chainId: 11142220,
                urls: {
                    apiURL: "https://api.etherscan.io/v2/api",
                    browserURL: "https://sepolia.celoscan.io",
                },
            },
            {
                network: "celo",
                chainId: 42220,
                urls: {
                    apiURL: "https://api.etherscan.io/v2/api",
                    browserURL: "https://celoscan.io/",
                },
            },
        ]
    },
```

## Verifying Contracts

Use the following command (Make sure your contracts are compiled before verification)

Celo Sepolia Testnet

```bash theme={null}
npx hardhat verify [CONTRACT_ADDRESS] [...CONSTRUCTOR_ARGS] --network celoSepolia
```

Celo Mainnet

```bash theme={null}
npx hardhat verify [CONTRACT_ADDRESS] [CONSTRUCTOR_ARGS] --network celo
```