# FastAPI
Confidence: high
Last verified: 2026-05-22
Generation: human_only


## TL;DR

FastAPI (Sebastian Ramirez, 2018) is a modern Python web framework for building APIs, emphasizing speed and automatic OpenAPI docs. Built on Starlette (web) and Pydantic (data validation). Async support native. Automatic interactive API docs (Swagger UI + ReDoc). One of the fastest-growing Python frameworks.

## Core Explanation

Path/query/body parameters with Python type hints — automatic validation, serialization, and docs. `@app.get('/items/{id}')` with `response_model=Item`. Dependency injection via `Depends()` — shared logic cleanly separated. Background tasks, WebSocket support, middleware (CORS, GZip). Performance comparable to Node.js/Go frameworks (benchmarked against Uvicorn).

## Further Reading

- [FastAPI Documentation](https://fastapi.tiangolo.com/)