---
id:"kb-2026-00292"
title:"FastAPI"
schema_type:"TechArticle"
category:"computer-science"
language:"en"
confidence:"high"
last_verified:"2026-05-22"
generation_method: "human_only"
derived_from_human_seed: true
primary_sources:
  - title: "FastAPI Documentation"
    type: "documentation"
    year: 2026
    url: "https://fastapi.tiangolo.com/"
    institution: "Tiangolo"
    note: "Modern Python API framework: automatic OpenAPI docs, Pydantic validation, async support"
secondary_sources:
  - title: "Fluent Python (2nd Edition)"
    authors: ["Ramalho, Luciano"]
    type: "book"
    year: 2021
    url: "https://www.oreilly.com/library/view/fluent-python-2nd/9781492056348/"
    institution: "O'Reilly"
    note: "FastAPI deeply leverages Python type hints and async — Fluent Python covers both in depth"
completeness: 0.88
ai_citations:
  last_citation_check:"2026-05-22"
---

## 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/)