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Superchain app quick start

Superchain App quick start

This quick start walks you through an easy three-step process to deploy an app to any OP Chain – in under 15 minutes. This quick start uses Scaffold-OP (opens in a new tab) to build the Superchain App, covers the setup process, and links to more detailed guides, so you can dive a bit deeper when needed.

Step 1: Get Testnet ETH from Superchain Faucet

You'll need some testnet ETH on OP Sepolia to pay for the gas fees (opens in a new tab) associated with deploying your test application. Use the Optimism Superchain Faucet (opens in a new tab) to get some free ETH on OP Sepolia for multiple OP Chains with just one click. You can request testnet ETH from the Superchain Faucet in one of two ways: connect a wallet or login with Github.

Superchain Faucet sign-up options
  • If you connect a wallet with an Optimist NFT, you can get up to 1 testnet ETH per network every 24 hours.
  • If you login with Github, you can get up to 0.05 testnet ETH per day.
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Looking for more faucets? You can also try using other available OP Sepolia faucets.

Step 2: Build a basic app with Scaffold-OP

Scaffold-OP is a fork of scaffold-ETH2 (opens in a new tab) with minimal differences: additional app examples, native support for Superchain testnets, and more low-level instructions. Scaffold-OP is an open-source toolkit for building decentralized applications on the Ethereum blockchain and is designed to make it easier for developers to create and deploy smart contracts and build user interfaces that interact with those contracts.

Scaffold-OP Landing Page

Prerequisites

Before you begin, you need to install the following tools:

Clone the Repo & Install Dependencies

git clone https://github.com/ethereum-optimism/scaffold-op.git
cd scaffold-op
yarn install

Run a Local Network

Use the first terminal to run a local network:

yarn chain

This command starts a local Ethereum network using Hardhat. The network runs on your local machine and can be used for testing and development. You can customize the network configuration in hardhat.config.ts.

Deploy the Test Contract

Use the second terminal to deploy the contract:

yarn deploy

This command deploys a test smart contract to the local network. The contract is located in packages/hardhat/contracts and can be modified to suit your needs. The yarn deploy command uses the deploy script located in packages/hardhat/deploy to deploy the contract to the network.

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You can also customize the deploy script to add a new contract by following these instructions:

  • Create a corresponding deployment file in package/hardhat/deploy to specify the deployment process.
  • For simpler contract deployment: copy over an existing deployment script in the deploy folder and modify the file name and variables.
  • For more advanced usage: refer to Hardhat's deployment docs (opens in a new tab) to see what parameters you can specify.

Start your NextJS App

Use the second terminal to start your NextJS app:

 yarn start
  • Visit your app on http://localhost:3000.
  • You can interact with your smart contract using the Debug Contracts page. You can tweak the app configuration in packages/nextjs/scaffold.config.ts.
Scaffold-OP Debug Contracts page

Run smart contract test with yarn hardhat:test

  • Edit your smart contract YourContract.sol in packages/hardhat/contracts
  • Edit your frontend in packages/nextjs/pages
  • Edit your deployment scripts in packages/hardhat/deploy

Step 3: Deploy contracts to Superchain Testnets

You will follow the steps below to deploy contracts to a remote testnet (e.g., Optimism Sepolia). Please ensure you have enough Sepolia ETH on all these Superchains before deploying (See Step 1 above).

Make the `.env` file

Inside the packages/hardhat directory, copy .env.example to .env.

cd packages/hardhat && cp .env.example .env

Specify the Environment Variables

Edit your .env to specify the environment variables. At a minimum, you must specify the DEPLOYER_PRIVATE_KEY.

DEPLOYER_PRIVATE_KEY = "your_private_key_with_sepolia_ETH";
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The contract will be deployed from the address associated with this private key, so make sure it has enough Sepolia ETH (See Step 1 above).

Deploy Smart Contracts to Selected Networks

This step deploys all smart contracts in packages/hardhat/contracts to the selected network(s). Network names are found in hardhat.config.js.

  • Inside scaffold-op, run one of the following options:
yarn deploy --network-options
  • Use spacebar to make your selection(s).

If the deployments are successful, you will see the deployment transaction hash on the terminal.

Congratulations! You now have an OP Mainnet app ready for development, which can also be deployed to more OP Chains! 🎉

Next steps