FastAPI framework, high performance, easy to learn, fast to code, ready for production
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**Documentation**: https://fastapi.tiangolo.com
**Source Code**: https://github.com/fastapi/fastapi
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# Overview
FastAPI is a modern, fast (high‑performance) web framework for building APIs with Python 3.8+ based on standard Python type hints. It combines the speed of **Node.js** and **Go** with the developer friendliness of **Python**, delivering:
* **Performance** – on par with the fastest Python frameworks because it is built on **Starlette** for the web parts and **Pydantic** for the data parts.
* **Fast to code** – increase development speed by 200 %–300 % thanks to automatic request validation, serialization, interactive API docs, and editor autocompletion.
* **Reduced bugs** – data validation and type checking catch many errors at runtime, lowering the chance of human‑introduced bugs.
* **Intuitive** – editors provide instant completion and type checking for request bodies, query parameters, headers, and more.
* **Production ready** – OpenAPI, JSON‑Schema, automatic interactive documentation (Swagger UI & ReDoc), dependency injection, security utilities, and extensive testing support.
# Installation
FastAPI is released on PyPI and can be installed with **pip**. It has no external runtime dependencies besides **uvicorn** (or another ASGI server) for development and production.
```bash
pip install "fastapi[all]" # includes optional dependencies such as python‑multipart, email‑validator, jinja2
# Or, if you only need the core framework:
pip install fastapi
```
> **Note**: FastAPI requires Python **3.8** or newer.
# Quick start
Below is a minimal example that demonstrates the core concepts:
```python
from fastapi import FastAPI
from pydantic import BaseModel
app = FastAPI()
class Item(BaseModel):
name: str
description: str | None = None
price: float
tax: float | None = None
@app.get("/items/{item_id}")
async def read_item(item_id: int, q: str | None = None):
return {"item_id": item_id, "q": q}
@app.post("/items/")
async def create_item(item: Item):
return {"item_id": 1, **item.dict()}
```
Run the application with **uvicorn**:
```bash
uvicorn myapp:app --reload # where `myapp.py` contains the code above
```
Open your browser at to see the automatically generated Swagger UI, or at for ReDoc.
For a more detailed tutorial, see the official documentation: .
# Documentation
The full documentation lives at . It covers:
* **Tutorial** – step‑by‑step guide for beginners.
* **Advanced user guide** – dependency injection, background tasks, websockets, security, testing, etc.
* **Reference** – exhaustive API reference for `fastapi`, `starlette`, and `pydantic` integration.
* **API OpenAPI schema** – automatically generated and customizable.
# Contributing
Contributions are welcome! Please read our [CONTRIBUTING guide](https://github.com/fastapi/fastapi/blob/master/CONTRIBUTING.md) before submitting a pull request. All contributors are expected to follow the code of conduct and ensure that new code is covered by tests and adheres to the project's style guidelines.
# License
FastAPI is licensed under the MIT License. See the `LICENSE` file for the full text.
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*FastAPI – The modern, fast (high‑performance) web framework for building APIs with Python.*