fastapi

FastAPI is a modern Python framework for building high-performance APIs using type hints and automatic validation. It handles routing, dependency injection, and data validation with Pydantic models, allowing you to create production-ready endpoints quickly with built-in async support and automatic documentation.

Use FastAPI's routing decorators to define endpoints and leverage dependency injection to manage shared logic, database connections, and authentication. Organize endpoints by resource, inject dependencies as function parameters, and FastAPI automatically resolves and validates them at request time.

FastAPI integrates Pydantic models for automatic request and response validation. Define models with type annotations, use them as endpoint parameters, and FastAPI validates incoming data against the schema, returning detailed errors and generating OpenAPI documentation automatically.

Yes, FastAPI supports background tasks for asynchronous processing and WebSockets for real-time bidirectional communication. Use BackgroundTasks to queue operations and WebSocket endpoints to maintain persistent connections for streaming data and live updates.

FastAPI testing uses the TestClient from Starlette to simulate requests without running a server. Write tests that call endpoints with test data, assert response status and content, and verify dependency behavior. Combine with Pydantic validation to ensure data integrity across test cases.

FastAPI requires Uvicorn as an ASGI server to run your application. For production, also consider adding async database drivers, environment configuration tools, and monitoring libraries. The Skill provides patterns for these integrations within a standard Python project setup.