Build Your First Web3 DApp: Complete Tutorial 2026
Build a DApp by: 1) Set up React + wagmi/viem 2) Connect wallet with ConnectKit/RainbowKit 3) Read contract state with hooks 4) Write transactions with proper error handling 5) Deploy contract and frontend.
Introduction
This tutorial walks through building a complete Web3 DApp from scratch. We will create a simple voting app that connects wallets, reads blockchain state, and submits transactions.
Prerequisites
- Node.js 18+
- Basic React knowledge
- MetaMask browser extension
- Sepolia testnet ETH (from faucet)
Project Setup
Create a new Next.js project with TypeScript and Tailwind. Install wagmi, viem, tanstack/react-query, and connectkit.
Configure Wagmi
Create a wagmi config with your chains (mainnet, sepolia) and transports. Use getDefaultConfig from connectkit for easy setup.
Wrap App with Providers
Wrap your app with WagmiProvider, QueryClientProvider, and ConnectKitProvider.
Connect Wallet Button
Use ConnectKitButton component for easy wallet connection.
Read Contract Data
Use useReadContract hook from wagmi to read blockchain state. Provide contract address, ABI, and function name.
Write to Contract
Use useWriteContract hook for transactions. Handle pending, confirming, and success states. Use useWaitForTransactionReceipt to wait for confirmation.
Testing
- Get Sepolia ETH from faucet
- Connect MetaMask to Sepolia
- Test wallet connection
- Test reading and writing
- Verify on Etherscan
Production Checklist
- Test on testnet thoroughly
- Audit smart contract
- Set up error monitoring
- Configure proper RPC endpoints
- Deploy to production L2
Conclusion
You have built a functional Web3 DApp! Key concepts: wagmi hooks for blockchain interaction, ConnectKit for wallets, and proper transaction handling. Expand this foundation to build more complex applications.
Key Takeaways
- Use viem/wagmi for modern Web3 development
- ConnectKit or RainbowKit for wallet connections
- Read operations are free, writes cost gas
- Always handle transaction failures gracefully
- Test on testnets before mainnet deployment
Frequently Asked Questions
Do I need to know Solidity?
For building frontends, you can interact with existing contracts without Solidity knowledge. To create your own contracts, you will need to learn Solidity basics.
Which network should I start with?
Start with Sepolia testnet for Ethereum development. It is free (faucet ETH) and behaves like mainnet. Move to mainnet or L2s like Base when ready for production.
Why do read operations from a smart contract cost nothing while writes cost gas?
Reads are free because they only query existing on-chain data without changing it, so no transaction is broadcast to the network. Writes cost gas because they modify blockchain state, which requires validators to process and confirm a transaction. This is why building a DApp means treating reads as cheap and instant while designing write flows carefully around gas and confirmation times.
What are wagmi and viem used for in a DApp?
Wagmi and viem are the modern libraries for connecting a frontend to the blockchain. Viem handles low-level interaction with Ethereum, such as encoding calls and sending transactions, while wagmi layers React hooks on top for reading contract state and managing wallet connections. Together they form the recommended foundation for building a DApp frontend in a React-based stack.
Which library should I use to add wallet connection?
ConnectKit and RainbowKit are the popular choices for adding wallet connection to a DApp. Both provide polished, ready-made interfaces that let users connect wallets like MetaMask with minimal setup, and they integrate cleanly with a wagmi and viem stack. Pick whichever styling and developer experience you prefer, since both handle the common connection flows so you do not build them from scratch.
About the Author
Marcus Williams
Blockchain & DeFi Editorial Desk
Blockchain & DeFi Editorial Desk · Web3AIBlog
Marcus Williams is a pen name for our blockchain and DeFi editorial desk. Posts under this byline are written and reviewed by contributors with backgrounds in protocol engineering, on-chain analysis, smart contract auditing, tokenomics, and decentralized finance. The desk covers consensus mechanisms, liquidity protocols, MEV, on-chain forensics, regulatory frameworks across jurisdictions, and the operational realities of running and using DeFi at scale. Our coverage is an editorial synthesis of protocol documentation, on-chain data, and audited primary sources, with every figure verified against a primary source before publication.
