Common Pitfalls in FastAPI: The Most Frequent Mistakes for Novice Developers

This article summarizes 8 common errors and their solutions in FastAPI development: 1. Parameter type confusion: Path parameters need explicit type declaration (e.g., `user_id: int`), query parameters are suitable for simple filtering, and complex data should use POST with Pydantic request body; 2. Pydantic models must correctly define types and inherit `BaseModel`, with field types matching input parameters; 3. Status codes should follow REST specifications (201 for resource creation, 204 for deletion); 4. CORS configuration requires `CORSMiddleware`, specifying frontend domain in production; 5. Use `asyncio.run_in_executor` when calling synchronous libraries from async functions; 6. Use `yield` for dependency injection to handle resource release, and import middleware from FastAPI's corresponding modules; 7. Routes must be registered with the app to generate documentation. It is recommended to refer to the official documentation, verify parameter types and status codes, and avoid issues like un释放ed resources.