Create an ERC20 token

Custom ERC20 token code

ERC20 tokens are a standard for fungible tokens, which can be traded and represent a fixed value. You’ve used ERC20 tokens if you’ve transacted with USDC, DAI, USDT, LINK or UNI.

The ERC20 token we’re going to deploy will allow users to mint and burn tokens. The entire smart contract code is as follows:

// SPDX-License-Identifier: Unlicensed
pragma solidity ^0.8.19;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol";

contract TestToken is ERC20, Ownable, ERC20Burnable {
    constructor(string memory name, string memory symbol) ERC20(name, symbol) {
        _mint(msg.sender, 100 * 10 ** decimals());
    }

    function mint(address to, uint256 amount) public onlyOwner {
        _mint(to, amount);
    }
}

The most important features are:

• Ownable : this extension sets the deployer account as owner of the smart contract. It also introduces the onlyOwner modifier that restricts the execution of certain functions to the owner of the contract.
• ERC20Burnable: this extension adds the burn and burnFrom functions to the smart contract. These functions destroy tokens from a given account.
• constructor: called on deployment, the constructor will assign the given name and symbol to the token and mint 100 units of it to the account that deployed the contract.
• mint : this function creates new token units to a given account. It uses the onlyOwner modifier so it can only be called from the owner account.

Deploy the smart contract

Atlas is a browser-based IDE with an integrated AI assistant that allows you to write, test and deploy smart contracts directly from your browser. Click the button below to open the project in Atlas.

You can see the contract in the Atlas code editor. In the right sidebar, make sure the selected network is “ZKsync Sepolia Testnet“ and click on "Deploy" to trigger the smart contract compilation and deployment.

Once compiled sign the transaction with your wallet and wait until its processed. You’ll see the contract in the “Deployed contracts” section.

Interact with the ERC20 contract

In the scripts folder you can find the mint-token.ts script containing the following code:

import { ethers } from "hardhat";

// Address of the ERC20 token contract
const TOKEN_CONTRACT_ADDRESS = "";
// Wallet that will receive tokens
const RECEIVER_WALLET = "";
// Amount of tokens to mint in ETH format, e.g. 1.23
const TOKEN_AMOUNT = "";

async function main() {
  const Token = await ethers.getContractFactory("TestToken");
  const tokenContract = Token.attach(TOKEN_CONTRACT_ADDRESS);

  console.log("Minting tokens...");

  const tx = await tokenContract.mint(
    RECEIVER_WALLET,
    ethers.parseEther(TOKEN_AMOUNT),
  );
  await tx.wait();

  console.log("Success!");
  console.log(
    `The account ${RECEIVER_WALLET} now has ${await tokenContract.balanceOf(
      RECEIVER_WALLET,
    )} tokens`,
  );
}

main()
  .then(() => process.exit(0))
  .catch((error) => {
    console.error(error);
    process.exit(1);
  });

This scripts uses ethers to interact with the contract we’ve just deployed.

Fill the following variables:

• TOKEN_CONTRACT_ADDRESS: the contract address of the ERC20 token we just deployed.
• RECEIVER_WALLET: address of a different account that will receive new tokens.
• TOKEN_AMOUNT: the amount of tokens we’ll send to the account.

With the mint-token.ts file open in the Atlas editor, click on the “Deploy” button to run the script and see the output in the terminal.

To confirm the account has received the tokens, visit the ZKsync Sepolia Testnet explorer and search the receiver wallet address. You’ll see the new token balance in the assets table:

Custom ERC20 token code

ERC20 tokens are a standard for fungible tokens, which can be traded and represent a fixed value. You’ve used ERC20 tokens if you’ve transacted with USDC, DAI, USDT, LINK or UNI.

The ERC20 token we’re going to deploy will allow users to mint and burn tokens. The entire smart contract code is as follows:

// SPDX-License-Identifier: Unlicensed
pragma solidity ^0.8.19;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol";

contract TestToken is ERC20, Ownable, ERC20Burnable {
    constructor(string memory name, string memory symbol)
      ERC20(name, symbol) Ownable(msg.sender) {
        _mint(msg.sender, 100 * 10 ** decimals());
    }

    function mint(address to, uint256 amount) public onlyOwner {
        _mint(to, amount);
    }
}

The most important features are:

• Ownable : this extension sets the deployer account as owner of the smart contract. It also introduces the onlyOwner modifier that restricts the execution of certain functions to the owner of the contract.
• ERC20Burnable: this extension adds the burn and burnFrom functions to the smart contract. These functions destroy tokens from a given account.
• constructor: called on deployment, the constructor will assign the given name and symbol to the token and mint 100 units of it to the account that deployed the contract.
• mint : this function creates new token units to a given account. It uses the onlyOwner modifier so it can only be called from the owner account.

Deploy the smart contract

The Remix IDE is an open-source web and desktop application that supports Ethereum smart contract development and deployment, offering tools for writing, testing, debugging, and deploying smart contracts written in Solidity to EVM compatible protocols.

Enable the Remix ZKsync plugin

To open this project in Remix, use the “Clone” option from the file explorer to import it from the following GitHub repository:https://github.com/ZKsync-Community-Hub/zksync-quickstart-remix

Once the project is imported, open the contracts/TestToken.sol file. To compile the contract, click on the ZKsync plugin on the left menu and then "Compile TestToken.sol". If you get a popup message requesting permissions to access ACCESS TO "WRITEFILE" OF "FILE MANAGER", click on Accept.

We will use our wallet’s configured network to connect and deploy our smart contract so make sure your wallet is currently connected to the ZKsync Sepolia Testnet. In Remix, under the Environment Section, select “Wallet” and click on “Connect Wallet”.

To deploy the contract, click on “Deploy” and sign the transaction on your wallet. Congratulations, your ERC20 token contract is now deployed on ZKsync Sepolia Testnet!

Interact with the ERC20 contract

In the scripts folder you can find the mint-token.ts script containing the following code:

import {ethers} from "ethers";

// Address of the ERC20 token contract
const TOKEN_CONTRACT_ADDRESS = ""
// Wallet that will receive tokens
const RECEIVER_WALLET    = "";
// Amount of tokens to mint in ETH format, e.g. 1.23
const TOKEN_AMOUNT    = "123.55";

(async () => {
  try {

  // Note that the script needs the ABI which is generated from the compilation artifact.
  // Make sure contract is compiled for ZKsync and artifacts are generated
  const artifactsPath = `browser/contracts/artifacts/TestToken.json` // Change this for different path

  const metadata = JSON.parse(await remix.call('fileManager', 'getFile', artifactsPath))

  // 'web3Provider' is a remix global variable object
  const signer = (new ethers.providers.Web3Provider(web3Provider)).getSigner(0)

  // initialise token contract with address, abi and signer
  const tokenContract= new ethers.Contract(TOKEN_CONTRACT_ADDRESS, metadata.abi, signer);

  console.log("Minting tokens...");
  const tx = await tokenContract.mint(
    RECEIVER_WALLET,
    ethers.utils.parseEther(TOKEN_AMOUNT)
  );
  console.log(`Mint transaction is ${tx.hash}`)
  await tx.wait();
  console.log("Success!");

  const balance = await tokenContract.balanceOf(RECEIVER_WALLET)

  console.log(`The account ${RECEIVER_WALLET} now has ${balance} tokens`)

  } catch (e) {
    console.log(e.message)
  }
})()

This scripts uses ethers to interact with the contract we’ve just deployed.

Fill the following variables:

• TOKEN_CONTRACT_ADDRESS: the contract address of the ERC20 token we just deployed.
• RECEIVER_WALLET: address of a different account that will receive new tokens.
• TOKEN_AMOUNT: the amount of tokens we’ll send to the account.

With the mint-token.ts file open in the editor, click on the “▶️” button to run the script and see the output in the terminal.

To confirm the account has received the tokens, visit the ZKsync Sepolia Testnet explorer and search the receiver wallet address. You’ll see the new token balance in the assets table: