Deploy an ERC-20 Using Hardhat¶

Introduction¶

ERC-20 tokens are fungible tokens commonly used for creating cryptocurrencies, governance tokens, and staking mechanisms. Polkadot Hub enables easy deployment of ERC-20 tokens via Ethereum-compatible smart contracts and tools.

This guide demonstrates how to deploy an ERC-20 contract on Polkadot Hub TestNet using Hardhat, an Ethereum development environment. The ERC-20 contract can be retrieved from OpenZeppelin's GitHub repository or generated with the OpenZeppelin Contracts Wizard for Polkadot.

Prerequisites¶

Before you begin, ensure you have the following:

• A basic understanding of Solidity programming and ERC-20 fungible tokens.
• Node.js v22.13.1 or later installed.
• Test tokens for gas fees, available from the Polkadot faucet. See Get Test Tokens for a guide to using the faucet.
• A wallet with a private key for signing transactions.

Set Up Your Project¶

This tutorial uses a Hardhat ERC-20 template that contains all the necessary files.

To get started, take the following steps:

1. Clone the GitHub repository locally:

   git clone https://github.com/polkadot-developers/revm-hardhat-examples/
   cd revm-hardhat-examples/erc20-hardhat
   

2. Install the dependencies using the following command:

   npm i
   

   This command will fetch all the necessary packages to help you use Hardhat to deploy an ERC-20 to Polkadot.

Configure Hardhat¶

If you started with the cloned Hardhat ERC-20 template, hardhat.config.ts is already configured to deploy to the Polkadot TestNet as shown in the example below:

import { HardhatUserConfig, vars } from "hardhat/config";
import "@nomicfoundation/hardhat-toolbox";

const config: HardhatUserConfig = {
  solidity: {
    version: "0.8.28",
    settings: {
      optimizer: {
        enabled: true,
        runs: 200,
      },
    },
  },
  networks: {
    polkadotTestnet: {
      url: vars.get("TESTNET_URL", "http://127.0.0.1:8545"),
      accounts: vars.has("TESTNET_PRIVATE_KEY") ? [vars.get("TESTNET_PRIVATE_KEY")] : [],
    },
  },
  mocha: {
    timeout: 40000,
  },
};

export default config;

Compile the Contract¶

Next, compile the contract included with the template by running the following command:

npx hardhat compile

If everything compiles successfully, you will see output similar to the following:

Test the Contract¶

You can view the predefined test file at test/MyToken.test.ts. This example test includes verification of the following:

• The token name and symbol exist (confirms deployment) and are correct.
• The token owner is correctly configured.
• The initial token supply is zero.
• The owner can mint tokens.
• The total supply increases after a mint.
• Successful mints to different test addresses with expected account balance and total supply changes.

Run the tests using the following command:

npx hardhat test --network polkadotTestnet

If tests are successful, you will see outputs similar to the following:

Deploy the Contract¶

You are now ready to deploy the contract to your chosen network. This example demonstrates deployment to the Polkadot TestNet. Deploy the contract as follows:

1. Run the following command in your terminal:

   npx hardhat ignition deploy ./ignition/modules/MyToken.ts --network polkadotTestnet
   

2. Confirm the target deployment network name and chain ID when prompted:

   npx hardhat ignition deploy ./ignition/modules/MyToken.ts --network polkadotTestnet ✔ Confirm deploy to network polkadotTestnet (420420417)? … yes   Hardhat Ignition 🚀   Deploying [ TokenModule ]   Batch #1 Executed TokenModule#MyToken   Batch #2 Executed TokenModule#MyToken.mint   [ TokenModule ] successfully deployed 🚀   Deployed Addresses   TokenModule#MyToken - 0xc01Ee7f10EA4aF4673cFff62710E1D7792aBa8f3

Congratulations! You've successfully deployed an ERC-20 token contract to Polkadot Hub TestNet using Hardhat. Consider the following resources to build upon your progress.

Where to Go Next¶