FastAPI is a modern web framework first released in 2018 for building RESTful APIs in Python.[3] It is used for building APIs with Python 3.8+ based on standard Python-type hints.
| Developer(s) | Sebastián Ramírez |
|---|---|
| Initial release | December 5, 2018[1] |
| Stable release | 0.111.0[2]  / 3 May 2024 |
| Repository | github |
| Written in | Python |
| Type | Web framework |
| License | MIT |
| Website | fastapi |
FastAPI is based on Pydantic and uses type hints to validate, serialize and deserialize data. It also automatically generates OpenAPI documentation for APIs built with it.[4]
Components
Pydantic
Pydantic is a data validation library for Python. While writing code in an IDE, Pydantic provides type hints for schema validation and serialization through type annotations.[5]
Starlette
Starlette is a lightweight ASGI framework/toolkit, to support async functionality in Python.[6]
Uvicorn
Uvicorn is a minimal low-level server/application web server for async frameworks, following the ASGI specification.
Example
The following code shows a simple web application that displays "Hello World!" when visited:
from fastapi import FastAPIapp = FastAPI()@app.get("/")def read_root(): return "Hello World!"