truffle-config.js

require("dotenv").config();
const HDWalletProvider = require("@truffle/hdwallet-provider");

module.exports = {
  plugins: [
    "truffle-plugin-verify"
  ],
  networks: {
    kovan: {
      provider: () => {
        return new HDWalletProvider({
          mnemonic: {
            phrase: process.env.MNEMONIC
          },
          providerOrUrl: process.env.NODE
        })
      },
      network_id: 42,
      gas: 4500000,
      confirmations: 2,
      timeoutBlocks: 200,
      skipDryRun: true,
    },
    development: {
      host: "localhost", // Localhost (default: none)
      port: 8545, // Standard Ethereum port (default: none)
      network_id: "*" // Any network (default: none)
    },
    mainnet: {
      provider: () => {
        return new HDWalletProvider({
          mnemonic: {
            phrase: process.env.MAIN_MNEMONIC
          },
          providerOrUrl: process.env.MAIN_NODE
        })
      },
      network_id: 1,
      gasPrice: 6000000000, // 6 gwei,
      confirmations: 2,
      timeoutBlocks: 200,
      skipDryRun: false,
    },
  },

  // Set default mocha options here, use special reporters etc.
  mocha: {
    // timeout: 100000
  },

  // Configure your compilers
  compilers: {
    solc: {
      version: "0.5.0",    // Fetch exact version from solc-bin (default: truffle's version)
      // docker: true,        // Use "0.5.1" you've installed locally with docker (default: false)
      // settings: {          // See the solidity docs for advice about optimization and evmVersion
      //  optimizer: {
      //    enabled: false,
      //    runs: 200
      //  },
      //  evmVersion: "byzantium"
      // }
    },
  },
  api_keys: {
    etherscan: process.env.ETH_SCAN_API_KEY
  }
};