概述
This sample app demonstrates Quicknode's x402 protocol for pay-per-request blockchain API access. The x402 protocol enables seamless micropayments for API calls — each request is paid for with an EVM signature, removing the need for traditional API keys or subscription plans.
Connect your wallet, authenticate with Sign-In with Ethereum (SIWE), and request testnet USDC from the faucet. When you execute blockchain methods, if you don't have enough credits, the app will automatically purchase test credits using your testnet USDC. Execute RPC/REST methods across multiple networks including Ethereum, Base Sepolia, Arbitrum, Polygon, and Aptos.
建筑
Wallet ──► SIWE Auth ──► JWT Token
│
▼
x402 Fetch Wrapper (JWT + EVM payment signature)
│
▼
Quicknode x402 API ──► Blockchain RPC / REST
Each API request is wrapped by @x402/fetch, which automatically signs a payment authorization using your connected wallet. The x402 backend verifies the signature, deducts credits, and proxies the request to the target blockchain network.
功能
- Wallet Connection via ConnectKit (MetaMask, Coinbase Smart Wallet, etc.)
- SIWE Authentication to receive a session JWT
- Testnet USDC Faucet on Base Sepolia — credits are automatically purchased with testnet USDC when needed
- Multi-Chain RPC/REST Execution across Ethereum, Base Sepolia, Arbitrum, Polygon, and Aptos
- Payment Metadata Inspection returned with each response
- JSON-RPC, REST, gRPC-Web, and WebSocket method support
支持的方法
As all JSON-RPC, REST, gRPC-Web, and WebSocket methods are supported, you can call any method available on the target network. For demonstration, the app includes buttons for popular methods:
| 方法 | 议定书 | 网络 |
|---|---|---|
eth_blockNumber | JSON-RPC | Base Sepolia, Arbitrum, Polygon |
eth_gasPrice | JSON-RPC | 塞波利亚基地 |
eth_chainId | JSON-RPC | 以太坊 |
| Ledger Info | REST | 阿普托斯 |
| Block by Height | REST | 阿普托斯 |
先决条件
项目结构
src/
├── app/ # Next.js App Router (pages & layouts)
├── components/
│ ├── providers.tsx # Wagmi + React Query + ConnectKit providers
│ └── wallet-connection-shell.tsx
├── hooks/
│ ├── use-x402-auth.ts # SIWE authentication state
│ ├── use-credits.ts # Credit balance fetching
│ └── use-x402-fetch.ts # Authenticated fetch wrapper
└── lib/
├── constants.ts # x402 URLs, chain IDs, contract addresses
├── methods.ts # Available RPC/REST method definitions
├── types.ts # TypeScript types
└── x402.ts # Core x402 logic (auth, credits, execution)
环境变量
| Variable | 默认 | 描述 |
|---|---|---|
NEXT_PUBLIC_X402_BASE_URL | https://x402.quicknode.com/ | x402 API base URL |
创建一个 .env.local file to override, but the default points to the public x402 endpoint which you can use for testing without any setup.
NEXT_PUBLIC_X402_BASE_URL=https://x402.quicknode.com/
入门指南
1. Clone the repository
git clone https://github.com/quiknode-labs/qn-guide-examples.git
cd qn-guide-examples/sample-dapps/x402-quicknode
2. Install dependencies
pnpm install
3. Start the development server
pnpm dev
Open http://localhost:3000 in your browser. Connect your wallet, authenticate with SIWE, request testnet USDC from the faucet, and start making pay-per-request API calls — credits are automatically purchased with your testnet USDC when needed.
预览
- 分叉该仓库
- 创建一个功能分支：git checkout -b feature/amazing-feature
- 提交您的更改：git commit -m "添加超棒的功能"
- 推送您的分支：git push origin feature/amazing-feature
- 提交一个拉取请求。
