FastAPI framework, high performance, easy to learn, fast to code, ready for production

--- **Documentation**: [https://fastapi.tiangolo.com](https://fastapi.tiangolo.com) **Source Code**: [https://github.com/fastapi/fastapi](https://github.com/fastapi/fastapi) --- FastAPI is a modern, fast (high-performance), web framework for building APIs with Python based on standard Python type hints. The key features are: * **Fast**: Very high performance, on par with **NodeJS** and **Go** (thanks to Starlette and Pydantic). [One of the fastest Python frameworks available](#performance). * **Fast to code**: Increase the speed to develop features by about 200% to 300%. * * **Fewer bugs**: Reduce about 40% of human (developer) induced errors. * * **Intuitive**: Great editor support. Completion everywhere. Less time debugging. * **Easy**: Designed to be easy to use and learn. Less time reading docs. * **Short**: Minimize code duplication. Multiple features from each parameter declaration. Fewer bugs. * **Robust**: Get production-ready code. With automatic interactive documentation. * **Standards-based**: Based on (and fully compatible with) the open standards for APIs: [OpenAPI](https://github.com/OAI/OpenAPI-Specification) (previously known as Swagger) and [JSON Schema](https://json-schema.org/). * estimation based on tests conducted by an internal development team, building production applications. ## Sponsors ### Keystone Sponsor

### Gold Sponsors

### Silver Sponsors

[Other sponsors](https://fastapi.tiangolo.com/fastapi-people/#sponsors) ## Opinions

"_[...] I'm using **FastAPI** a ton these days. [...] I'm actually planning to use it for all of my team's **ML services at Microsoft**. Some of them are getting integrated into the core **Windows** product and some **Office** products._"

Kabir Khan - Microsoft (ref)

--- "_We adopted the **FastAPI** library to spawn a **REST** server that can be queried to obtain **predictions**. [for Ludwig]_"

Piero Molino, Yaroslav Dudin, and Sai Sumanth Miryala - Uber (ref)

--- "_**Netflix** is pleased to announce the open-source release of our **crisis management** orchestration framework: **Dispatch**! [built with **FastAPI**]_"

Kevin Glisson, Marc Vilanova, Forest Monsen - Netflix (ref)

--- "_If anyone is looking to build a production Python API, I would highly recommend **FastAPI**. It is **beautifully designed**, **simple to use** and **highly scalable**, it has become a **key component** in our API first development strategy and is driving many automations and services such as our V …

Deon Pillsbury - Cisco (ref)

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## FastAPI mini documentary There's a [FastAPI mini documentary](https://www.youtube.com/watch?v=mpR8ngthqiE) released at the end of 2025, you can watch it online: ## **Typer**, the FastAPI of CLIs

If you are building a CLI app to be used in the terminal instead of a web API, check out [**Typer**](https://typer.tiangolo.com/). **Typer** is FastAPI's little sibling. And it's intended to be the **FastAPI of CLIs**. ⌨️ 🚀 ## Requirements FastAPI stands on the shoulders of giants: * [Starlette](https://starlette.dev/) for the web parts. * [Pydantic](https://pydantic.dev/docs/) for the data parts. ## Installation First, [install `uv`](https://docs.astral.sh/uv/getting-started/installation/), and then add FastAPI to your project:

```console $ uv add "fastapi[standard]" ---> 100% ```

**Note**: Make sure you put `"fastapi[standard]"` in quotes to ensure it works in all terminals. If you prefer to use `pip`, install `fastapi[standard]` inside a virtual environment. See the [installation guide](tutorial/#install-fastapi) for the alternative steps. ## Example ### Create it Create a file `main.py` with: ```Python from fastapi import FastAPI app = FastAPI() @app.get("/") def read_root(): return {"Hello": "World"} @app.get("/items/{item_id}") def read_item(item_id: int, q: str | None = None): return {"item_id": item_id, "q": q} ```

Or use async def...

If your code uses `async` / `await`, use `async def`: ```Python hl_lines="7 12" from fastapi import FastAPI app = FastAPI() @app.get("/") async def read_root(): return {"Hello": "World"} @app.get("/items/{item_id}") async def read_item(item_id: int, q: str | None = None): return {"item_id": item_id, "q": q} ``` **Note**: If you don't know, check the _"In a hurry?"_ section about [`async` and `await` in the docs](https://fastapi.tiangolo.com/async/#in-a-hurry).

### Run it Run the server with:

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