Contract Development on Testnet

When developing smart contracts on Testnet, use the Testnet version of the Cronos Explorer block explorer:

• Cronos Explorer Testnet URL: https://explorer.cronos.org/testnet

• Documentation of Cronos Explorer Testnet API: https://explorer-api-doc.cronos.org/testnet

Truffle: Deploy ERC20 Contract

Step 1. Enter smart-contract-example/truffle folder

$ cd cronos-smart-contract-example/truffle

Step 2. Run npm install inside the folder

$ npm install

Step 3. Make a copy of .env.example to .env

$ cp .env.example .env

Step 4. Modify .env and fill ONE of the field

MNEMONIC=goose easy ivory ...
PRIVATE_KEY=XXXXXXX

Step 5. Review Migration Script at migrations/2_deploy_cronos_token.js

  const CronosToken = artifacts.require("CronosToken");
  
  module.exports = function (deployer) {
      deployer.deploy(CronosToken, "Cronos Token", "CRT", "1000000000000000000000000");
  };

Step 6. Endpoints setting

By default, the script will be using your local host "127.0.0.1" - If you are not running a localhost, you may leverage the public endpoint https://evm-t3.cronos.org/ by making changes to networks in truffle-config.js, for example:

  networks: {
    development: {
      provider: new HDWalletProvider(getHDWallet(), "http://127.0.0.1:8545"), // TODO
      network_id: "*",       // Any network (default: none)
    },
    testnet: {
      provider: new HDWalletProvider(getHDWallet(), "https://evm-t3.cronos.org/"), // TODO
      network_id: "*",
      skipDryRun: true
    },
  },

Step 7. Deploy Contract

npm run deploy-contract-cronos

Step 8. Obtain Contract address from console and input to Metamask

Correct balance will be shown on Metamask page

Hardhat: Deploy ERC20 Contract

Step 1. Enter smart-contract-example/hardhat folder

$ cd smart-contract-example/hardhat

Step 2. Run npm install inside the folder

$ npm install

Step 3. Make a copy of .env.example to .env

$ cp .env.example .env

Step 4. Modify .env and fill ONE of the field

MNEMONIC=goose easy ivory ...
PRIVATE_KEY=XXXXXXX

Step 5. Review Migration Script at scripts/deploy-cronos-token.js

  async function main() {
      const CronosToken = await hre.ethers.getContractFactory("CronosToken");
      const cronosToken = await CronosToken.deploy("Cronos Token", "CRT", "1000000000000000000000000");
  
      await cronosToken.deployed();
  
      console.log("CronosToken deployed to:", cronosToken.address);
  }

Step 6. Endpoints setting

By default, the script will be using your local host "127.0.0.1" - If you are not running a localhost, you may leverage the public endpoint https://evm-t3.cronos.org/ by making changes to networks in hardhat.config.js, for example:

  networks: {
    development: {
      url: "http://localhost:8545",
      accounts: getHDWallet(),
     },
    testnet: {
      url: "https://evm-t3.cronos.org/",
      accounts: getHDWallet(),
    },
  },

Step 7. Deploy Contract

npm run deploy-contract-cronos

Step 8. Obtain Contract address from console and input to Metamask

Correct balance will be shown on Metamask page

CronosToken deployed to: 0x5F803c894a0A16B46fe5982fB5D89eb334eAF68