hardhat.config.js

require('dotenv').config();
require("@nomiclabs/hardhat-ethers");
require("@nomiclabs/hardhat-etherscan");

const { API_URL, PRIVATE_KEY } = process.env;
const ETHERSCAN_API_KEY = process.env.ETHERSCAN_API_KEY;

module.exports = {
  solidity: "0.7.3",
  defaultNetwork: "ropsten",
  networks: {
      hardhat: {},
      ropsten: {
         url: API_URL,
         accounts: [`0x${PRIVATE_KEY}`]
      }
  },
  etherscan: {
    // Your API key for Etherscan
    // Obtain one at https://etherscan.io/
    apiKey: ETHERSCAN_API_KEY
  }
};