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Contract Verification

📜 TL;DR:

  • This guide explains how to verify smart contracts deployed on the Hemi blockchain using two methods:

    1. API-based verification using tools like Hardhat and Foundry/Forge.

    2. Manual UI-based verification via Blockscout.

🏁 Prerequisites

  • Hemi RPC URL and deployed contract address.

  • Contract source code available (flattened only if verifying manually via the Hemi Blockscout UI).

  • API key from Hemi Blockscout (only needed for API-based verification).

🚧 API-Based Contract Verification

API-based verification is the preferred method since it automates the process using development tools like Hardhat or Foundry/Forge.

Hardhat Verification

1. Install dependencies

If you haven't already installed Hardhat and the Etherscan plugin (adapted for Blockscout), run the following:

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

2. Configure Hardhat for Hemi

In your `hardhat.config.js`, set up the Hemi network and include Blockscout API key information for contract verification:

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

module.exports = {
  solidity: "0.8.4",
  networks: {
    hemi: {
      url: "RPC_URL",
      accounts: [process.env.PRIVATE_KEY]
    }
  },
  etherscan: {
    apiKey: {
      hemi: "YOUR_BLOCKSCOUT_API_KEY"
    },
    customChains: [
      {
        network: "Hemi Sepolia",
        chainId: 743111, // Hemi Sepolia Chain ID
        urls: {
          apiURL: "API_URL",
          browserURL: "https://testnet.explorer.hemi.xyz"
        }
      }
      {
        network: "Hemi Mainnet",
        chainId: 43111, // Hemi mainnet Chain ID
        urls: {
          apiURL: "MAINNET_API_URL",
          browserURL: "MAINNET_EXPLORER_URL"
        }
      }    
    ]
  }
};

3. Deploy your contract

Deploy your contract using Hardhat (assuming it hasn’t already been deployed):

npx hardhat run scripts/deploy.js --network hemi

4. Verify the contract 🎉

Once deployed, you can verify the contract using Hardhat’s `verify` command. Make sure to include any constructor arguments if necessary:

npx hardhat verify --network hemi <DEPLOYED_CONTRACT_ADDRESS> "Constructor Argument 1" "Constructor Argument 2"

Foundry / Forge Verification

1. Install Foundry

If you haven’t installed Foundry, you can do so by running:

curl -L https://foundry.paradigm.xyz | bash
foundryup

2. Set Up Forge Project

To set up a Forge project, initialize the project:

mkdir my-foundry-project
cd my-foundry-project
forge init

3. Deploy your contract

Deploy your contract to Hemi using Forge:

forge create --rpc-url <URL> --private-key $PRIVATE_KEY src/MyContract.sol:MyContract

4. Verify the contract 🎉

Use the following command to verify the contract using the Blockscout API:

forge verify-contract --chain-id 743111 --etherscan-api-key YOUR_BLOCKSCOUT_API_KEY --watch CONTRACT_ADDRESS src/MyContract.sol:MyContract

Make sure to replace YOUR_BLOCKSCOUT_API_KEY and CONTRACT_ADDRESS with your actual values.

Blockscout UI Verification

Manual verification is performed directly through the Blockscout UI. This method requires flattening the contract source code and uploading it manually.

1. Flatten the contract

Flattening a contract is necessary when verifying through the UI.

For Hardhat:

npx hardhat flatten contracts/MyContract.sol > MyContractFlattened.sol

For Foundry:

forge flatten src/MyContract.sol > MyContractFlattened.sol

2. Access Hemi Blockscout

Go to Hemi Blockscout Explorer and navigate to the Verify & Publish Contract page.

3. Input contract information

Input your deployed contract address, contract license, and contract verification method.

4. Submit for verification 🎉

Once the required details are entered, submit the form. Blockscout will match the uploaded source code with the deployed bytecode, and if they match, your contract will be verified.

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