* Help me check that the PR has **tests**.

* Check that the tests **fail** before the PR. 🚨

* Then check that the tests **pass** after the PR. ✅

* Many PRs don't have tests, you can **remind** them to add tests, or you can even **suggest** some tests yourself. That's one of the things that consume most time and you can help a lot with that.

* Then also comment what you tried, that way I'll know that you checked it. 🤓

Nutzen Sie den Chat nur für andere allgemeine Gespräche.

///

### Den Chat nicht für Fragen verwenden

Si puedes ayudarme con eso, **me estás ayudando a mantener FastAPI** y asegurando que siga **avanzando más rápido y mejor**. 🚀

## Únete al chat

Únete al servidor de chat 👥 <a href="https://discord.gg/VQjSZaeJmf" class="external-link" target="_blank">Discord</a> 👥 y charla con otros en la comunidad de FastAPI.

/// tip | Consejo

Use o chat apenas para outro tipo de assunto.

///

### Não faça perguntas no chat

  stars: 5978
  owner_login: hatchet-dev
  owner_html_url: https://github.com/hatchet-dev
- name: serge
  html_url: https://github.com/serge-chat/serge
  stars: 5751
  owner_login: serge-chat
  owner_html_url: https://github.com/serge-chat
- name: fastapi-users
  html_url: https://github.com/fastapi-users/fastapi-users
  stars: 5517
  owner_login: fastapi-users

* Then close one of the tabs.

That will raise the `WebSocketDisconnect` exception, and all the other clients will receive a message like:

```
Client #1596980209979 left the chat
```

/// tip

The app above is a minimal and simple example to demonstrate how to handle and broadcast messages to several WebSocket connections.

    finally:
        some_cleanup()
```

...that way the `finally` block is run regardless of any exception that might happen.

### Features

* The same PR [#4575](https://github.com/tiangolo/fastapi/pull/4575) from above also fixes the `contextvars` context for the code before and after `yield`. This was the main objective of that PR.

...
```

#### What is OpenAPI for { #what-is-openapi-for }

The OpenAPI schema is what powers the two interactive documentation systems included.

And there are dozens of alternatives, all based on OpenAPI. You could easily add any of those alternatives to your application built with **FastAPI**.

This decoupling of parts, and being a "microframework" that could be extended to cover exactly what is needed was a key feature that I wanted to keep.

Given the simplicity of Flask, it seemed like a good match for building APIs. The next thing to find was a "Django REST Framework" for Flask.

/// check | Inspired **FastAPI** to

* **Nhanh**: Hiệu năng rất cao khi so sánh với **NodeJS** và **Go** (cảm ơn Starlette và Pydantic). [Một trong những Python framework nhanh nhất](#hieu-nang).
* **Code nhanh**: Tăng tốc độ phát triển tính năng từ 200% tới 300%. *
* **Ít lỗi hơn**: Giảm khoảng 40% những lỗi phát sinh bởi con người (nhà phát triển). *