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FastAPI Server Example

Example FastAPI server with X402 payment requirements.

Setup

  1. Install dependencies: 

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    pip install -r requirements.txt

  2. Configure environment: 

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    cp .env.example .env
# Edit .env with your wallet address and token mint

  3. Run the server: 

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    python main.py

  4. Visit http://localhost:8000/docs for API documentation

Testing

Get free data:

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curl http://localhost:8000/free-data

Try premium endpoint (will return 402):

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curl http://localhost:8000/premium-data

With payment client:

See the langchain-agent example for how to make payments automatically.

Endpoints

  • GET / - API information (free)
  • GET /free-data - Free data (no payment)
  • GET /premium-data - Premium data (0.10 USDC)
  • GET /expensive-data - Expensive AI data (1.00 USDC)
  • GET /tiered-data/{tier} - Tiered access (0.05 USDC)