hardhat.config.js

const { version } = require("chai");

require("@nomiclabs/hardhat-waffle");
require("hardhat-deploy");
require("@nomiclabs/hardhat-ethers");
require("@nomiclabs/hardhat-etherscan");

// This is a sample Hardhat task. To learn how to create your own go to
// https://hardhat.org/guides/create-task.html
task("accounts", "Prints the list of accounts", async (taskArgs, hre) => {
  const accounts = await hre.ethers.getSigners();

  for (const account of accounts) {
    console.log(account.address);
  }
});

// You need to export an object to set up your config
// Go to https://hardhat.org/config/ to learn more

require('dotenv').config()
const RINKEBY_RPC_URL = process.env.RINKEBY_RPC_URL
const MNEMONIC = process.env.MNEMONIC
const ETHERSCAN_API_KEY = process.env.ETHERSCAN_API_KEY
/**
 * @type import('hardhat/config').HardhatUserConfig
 */
module.exports = {
  defaultNetwork: "hardhat",
  networks: {
    hardhat: {},
    rinkeby: {
      url: RINKEBY_RPC_URL,
      accounts: {
        mnemonic: MNEMONIC
      },
      saveDeployments: true,
    },
    polygon: {
      url: 'https://polygon-mumbai.g.alchemy.com/v2/89cnHdzCHXzONYZj9q7ddITaWfHuD1xE',
      accounts: {
        mnemonic: MNEMONIC
      },
      saveDeployments: true
    }
  },
  etherscan: {
    apiKey: ETHERSCAN_API_KEY
  },
  solidity: {
    compilers: [
      {version: "0.8.0"}, {version: "0.4.24"}, {version: "0.6.6"}, {version: "0.7.0"}
    ]
  },
  namedAccounts: {
    deployer: {
      default: 0
    }
  }
};