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FastAPI

Modern, fast Python web framework for building APIs with automatic OpenAPI docs and type validation.

Version: v0.111

Official Documentation ↗

Installation

pippip install fastapi uvicorn

Methods

FAQ

How does FastAPI compare to Flask?
FastAPI provides automatic type validation, OpenAPI/Swagger docs, and async support out of the box. Flask requires extensions for these features. FastAPI is also faster, benchmarking at par with NodeJS and Go frameworks.
What is the ASGI server requirement?
FastAPI requires an ASGI server like Uvicorn (dev) or Hypercorn/Gunicorn with uvicorn worker (prod). This enables async/await support for concurrent request handling and WebSockets.
How do I handle database connections?
Use SQLAlchemy 2.0 with async sessions, or SQLModel (built on Pydantic + SQLAlchemy). For NoSQL, Motor (MongoDB) or Redis async. Dependency injection manages connection lifecycle per request.