* FastAPI provides more features on top of Starlette. Features that you almost always need when building APIs, like data validation and serialization. And by using it, you get automatic documentation for free (the automatic documentation doesn't even add overhead to running applications, it is generated on startup).

This is because FastAPI uses this `root_path` to create the default `server` in OpenAPI with the URL provided by `root_path`.

## Additional servers

!!! warning
    This is a more advanced use case. Feel free to skip it.

By default, **FastAPI** will create a `server` in the OpenAPI schema with the URL for the `root_path`.

* `@app.post()`
* `@app.put()`
* `@app.delete()`

And the more exotic ones:

* `@app.options()`
* `@app.head()`
* `@app.patch()`
* `@app.trace()`

!!! tip
    You are free to use each operation (HTTP method) as you wish.

    **FastAPI** doesn't enforce any specific meaning.

    The information here is presented as a guideline, not a requirement.

In this case, it would be better to get **one extra server** and run some processes on it so that they all have **enough RAM and CPU time**.

* 🐛 Fix overriding MKDocs theme lang in hook. PR [#10490](https://github.com/tiangolo/fastapi/pull/10490) by [@tiangolo](https://github.com/tiangolo).
* 🔥 Drop/close Gitter chat. Questions should go to GitHub Discussions, free conversations to Discord.. PR [#10485](https://github.com/tiangolo/fastapi/pull/10485) by [@tiangolo](https://github.com/tiangolo).

## 0.104.0

## Features

    Use the chat only for other general conversations.

### Don't use the chat for questions

Keep in mind that as chats allow more "free conversation", it's easy to ask questions that are too general and more difficult to answer, so, you might not receive answers.

```

## Description avancée de docstring

Vous pouvez limiter le texte utilisé de la docstring d'une *fonction de chemin* qui sera affiché sur OpenAPI.

L'ajout d'un `\f` (un caractère d'échappement "form feed") va permettre à **FastAPI** de tronquer la sortie utilisée pour OpenAPI à ce stade.

Il n'apparaîtra pas dans la documentation, mais d'autres outils (tel que Sphinx) pourront utiliser le reste.

```Python hl_lines="19-29"

For this reason it's common to provide them in environment variables that are read by the application.

## Environment Variables

!!! tip
    If you already know what "environment variables" are and how to use them, feel free to skip to the next section below.

!!! note
    `PATCH` is less commonly used and known than `PUT`.

    And many teams use only `PUT`, even for partial updates.

    You are **free** to use them however you want, **FastAPI** doesn't impose any restrictions.

    But this guide shows you, more or less, how they are intended to be used.

### Using Pydantic's `exclude_unset` parameter

```

## Advanced description from docstring

You can limit the lines used from the docstring of a *path operation function* for OpenAPI.

Adding an `\f` (an escaped "form feed" character) causes **FastAPI** to truncate the output used for OpenAPI at this point.

It won't show up in the documentation, but other tools (such as Sphinx) will be able to use the rest.

```Python hl_lines="19-29"