What is hardhat

Hardhat is a development environment for Ethereum software. It consists of different components for editing, compiling, debugging and deploying your smart contracts and dApps, all of which work together to create a complete development environment.

How to use hardhat on Fuse and Spark

Following the instructions here, run npx hardhat to create a hardhat project.

Then in hardhat.config.js add Fuse and Spark to the network section:

hardhat.config.js

module.exports = {
  // ...
  networks: {
    fuse: {
      url: 'https://rpc.fuse.io/',
      accounts: {
        // put dev menomonic or PK here
      },
    },
    spark: {
      url: 'https://rpc.fusespark.io/',
      accounts: {
        // put dev menomonic or PK here
      },
    },
  },
  // ...
}

How to verify contracts

To verify contracts with hardhat the hardhat-etherscan is used. Yes it’s sound counterintuitive and wrong, but the hardhat-etherscan plugin verifies contracts in the blockscout explorer.

Add the following property to hardhat.config.js

hardhat.config.js

etherscan: {
    apiKey: {
      fuse: "YOUR_KEY_IF_YOU_HAVE_ONE",
      spark: "YOUR_KEY_IF_YOU_HAVE_ONE"
    },
    customChains: [
      {
        network: "fuse",
        chainId: 122,
        urls: {
          apiURL: "https://explorer.fuse.io/api",
          browserURL: "https://explorer.fuse.io"
        }
      },
      {
        network: "spark",
        chainId: 123,
        urls: {
          apiURL: "https://explorer.fusespark.io/api",
          browserURL: "https://explorer.fusespark.io"
        }
      }
    ]
  }

Now to verify the contract on Fuse:

npx hardhat verify --network fuse DEPLOYED_CONTRACT_ADDRESS "Constructor argument 1"