Building dApps with Scaffold-ETH 2 on Kaia

Decentralized applications (dApps) are transforming how developers build and deploy digital solutions on blockchain networks. With tools like Scaffold-ETH 2, creating full-stack dApps on EVM-compatible chains such as Kaia has never been easier. This powerful open-source toolkit streamlines smart contract development, deployment, and frontend integration using modern web3 technologies.

In this comprehensive guide, you'll learn how to set up a development environment, configure Hardhat and Next.js, deploy smart contracts to the Kairos Testnet, and launch a fully functional dApp using Scaffold-ETH 2. Whether you're new to web3 or an experienced developer, this step-by-step walkthrough will help you get started building on Kaia.

Prerequisites for Development

Before diving into the setup process, ensure your system meets the following requirements:

Node.js (version >= v18.17)
Yarn package manager (v1 or v2+)
Basic understanding of JavaScript and React fundamentals, including hooks
A MetaMask wallet installed and configured
Test KAIA tokens from the Kaia faucet
Access to a Kaia RPC endpoint via supported providers

These tools form the foundation of your development stack and are essential for interacting with the Kaia network.

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Setting Up Your Scaffold-ETH 2 Environment

Scaffold-ETH 2 offers two installation methods: cloning the GitHub repository or using the npx command. For simplicity and speed, we’ll use the latter approach.

Run the following command in your terminal:

npx create-eth@latest

You’ll be prompted with several configuration options:

Project Name: Enter a name like kaia-scaffold-example
Framework Selection: Choose between Hardhat or Foundry. In this guide, we'll use Hardhat
Install Packages: Press Enter to accept the default "yes" option

Once installation completes, navigate into your project directory:

cd kaia-scaffold-example

This initializes a complete development environment with pre-built components including smart contracts, deployment scripts, and a React-based frontend powered by Next.js, RainbowKit, and Wagmi.

Key Steps in the Scaffold-ETH 2 Workflow

The typical development cycle using Scaffold-ETH 2 involves the following stages:

Update Hardhat network configuration for Kaia
Add or modify Solidity smart contracts in packages/hardhat/contracts
Customize deployment scripts in packages/hardhat/deploy
Deploy contracts to the Kairos Testnet
Verify deployed contracts using Hardhat plugins
Configure the frontend in packages/nextjs/scaffold.config.ts to target Kaia
Customize UI components under packages/nextjs/pages

We'll focus on adapting the default example contract and frontend to work seamlessly with Kaia.

Configuring Hardhat for Kaia

To interact with the Kaia blockchain, you need to configure Hardhat with the correct network settings and credentials.

Step 1: Create a `.env` File

Start by creating a .env file in the Hardhat package directory:

touch packages/hardhat/.env

Refer to .env.example for reference variables. For Kaia, only one key is required:

deployer_private_key=insert_private_key

Replace insert_private_key with the private key of the MetaMask account that will deploy and interact with contracts on Kaia.

Step 2: Update `hardhat.config.ts`

Modify the hardhat.config.ts file to include Kaia’s network configuration. Set the defaultNetwork to kairos and add the following network object:

kairos: {
  chainId: 1001,
  url: "https://public-en-kairos.node.kaia.io",
  accounts: [deployerPrivateKey],
},

Ensure the deployerPrivateKey is loaded from your .env file using dotenv.

Step 3: Deploy Contracts to Kaia

Compile your contracts first:

yarn compile

Then deploy them to the Kairos Testnet:

yarn deploy --network kairos

If no default network is set, always specify --network kairos to avoid deployment errors.

Step 4: Verify Deployed Contracts

To verify your contract on Kaiascope (Kaia’s block explorer), add Etherscan-compatible verification settings in hardhat.config.ts:

etherscan: {
  apiKey: {
    kairos: "unnecessary",
  },
  customChains: [
    {
      network: "kairos",
      chainId: 1001,
      urls: {
        apiURL: "https://api-baobab.klaytnscope.com/api",
        browserURL: "https://kairos.kaiascope.com",
      },
    },
  ],
},

Verify your contract using:

yarn hardhat verify --network kairos CONTRACT_ADDRESS "constructor_arg_if_any"

Example:

yarn hardhat verify --network kairos 0x7fc9656fc8c8ab433867e58b7c6afc19ec4275da

Upon success, you'll receive a confirmation and a link to view your verified contract on Kaiascope.

Frontend Configuration with Next.js

Now that your contract is live, configure the frontend to connect to Kaia.

Targeting Kairos Testnet in `scaffold.config.ts`

Open packages/nextjs/scaffold.config.ts and update the targetNetworks array:

targetNetworks: [chains.klaytnBaobab],

This tells the frontend to connect to Kaia’s testnet and interact with deployed contracts.

Launching the dApp Locally

Start the development server:

yarn start

Visit http://localhost:3001 to access your dApp. You can now:

Connect your MetaMask wallet
Interact with contract functions via the UI
Debug transactions using built-in tools

Your dApp is now fully integrated with Kaia’s blockchain.

Frequently Asked Questions

What is Scaffold-ETH 2 used for?

Scaffold-ETH 2 is a full-stack toolkit that simplifies dApp development on EVM-compatible blockchains. It combines Hardhat, Foundry, Next.js, RainbowKit, and Wagmi to provide a seamless workflow for deploying smart contracts and building interactive frontends.

Can I use Scaffold-ETH 2 on non-Ethereum blockchains?

Yes. Scaffold-ETH 2 supports any EVM-compatible chain, including Kaia, Polygon, BSC, and Avalanche. You just need to configure network settings and RPC endpoints accordingly.

How do I get test KAIA tokens?

Visit the official Kaia faucet and connect your wallet to receive free testnet KAIA tokens for development and testing.

Is it necessary to verify smart contracts?

While not mandatory, contract verification increases transparency and trust. Verified contracts can be audited and explored on block explorers like Kaiascope.

What tools does Scaffold-ETH 2 include?

Key tools include Hardhat or Foundry for contract development, Next.js for frontend rendering, RainbowKit for wallet connection, and Wagmi for web3 hooks—all written in TypeScript.

Can I customize the default dApp template?

Absolutely. The scaffold includes modular components that you can extend or replace. Modify contracts, styles, pages, and deployment scripts to suit your project needs.

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Conclusion

You’ve successfully deployed a smart contract and launched a dApp on Kaia using Scaffold-ETH 2. By configuring Hardhat for deployment and Next.js for frontend interaction, you’ve built a complete web3 application ready for further customization.

With this foundation, you can now experiment with more complex contracts, integrate additional features like NFTs or token swaps, and prepare for mainnet deployment. The modular nature of Scaffold-ETH 2 makes it ideal for rapid prototyping and scalable development on Kaia and other EVM chains.

For further learning, check out the Scaffold-ETH 2 documentation or join discussions on the Kaia developer forum.

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