Also, there might be tools that expect and use it (now or in the future) and that might be useful for you or your users, now or in the future.

That's the benefit of standards...

///

## See it in action { #see-it-in-action }

Open the interactive docs: <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

{* ../../docs_src/dependencies/tutorial001_02_an_py310.py hl[12,16,21] *}

/// tip

This is just standard Python, it's called a "type alias", it's actually not specific to **FastAPI**.

But because **FastAPI** is based on the Python standards, including `Annotated`, you can use this trick in your code. 😎

///

///

/// info

OpenAPI 3.1.0 (used since FastAPI 0.99.0) added support for `examples`, which is part of the **JSON Schema** standard.

Before that, it only supported the keyword `example` with a single example. That is still supported by OpenAPI 3.1.0, but is deprecated and is not part of the JSON Schema standard. So you are encouraged to migrate `example` to `examples`. 🤓

You can read more at the end of this page.

///

## Dependencies { #dependencies }

FastAPI depends on Pydantic and Starlette.

### `standard` Dependencies { #standard-dependencies }

When you install FastAPI with `pip install "fastapi[standard]"` it comes with the `standard` group of optional dependencies:

Used by Pydantic:

Vous faites cela avec les types Python standard modernes.

Vous n'avez pas à apprendre une nouvelle syntaxe, les méthodes ou les classes d'une bibliothèque spécifique, etc.

Juste du **Python** standard.

Par exemple, pour un `int`:

```Python
item_id: int
```

ou pour un modèle `Item` plus complexe :

## Dependencies { #dependencies }

FastAPI depends on Pydantic and Starlette.

### `standard` Dependencies { #standard-dependencies }

When you install FastAPI with `pip install "fastapi[standard]"` it comes with the `standard` group of optional dependencies:

Used by Pydantic:

![ReDoc](https://fastapi.tiangolo.com/img/index/index-02-redoc-simple.png)

### OpenAPI

**FastAPI** generiert ein „Schema“ mit all Ihren APIs unter Verwendung des **OpenAPI**-Standards zur Definition von APIs.

#### „Schema“

Ein „Schema“ ist eine Definition oder Beschreibung von etwas. Nicht der eigentliche Code, der es implementiert, sondern lediglich eine abstrakte Beschreibung.

#### API-„Schema“

	//
	// Reference:
	//	http://pubs.opengroup.org/onlinepubs/009695399/utilities/pax.html
	FormatPAX

	// FormatGNU represents the GNU header format.
	//
	// The GNU header format is older than the USTAR and PAX standards and
	// is not compatible with them. The GNU format supports
	// arbitrary file sizes, filenames of arbitrary encoding and length,
	// sparse files, and other features.
	//

Dans ce cas, l'URL serait : `/files//home/johndoe/myfile.txt`, avec un double slash (`//`) entre `files` et `home`.

///

## Récapitulatif

Avec **FastAPI**, en utilisant les déclarations de type rapides, intuitives et standards de Python, vous bénéficiez de :

* Support de l'éditeur : vérification d'erreurs, auto-complétion, etc.

      createConstantUtf8(APPLICATION_TYPE, "manifest+json");

  /**
   * <a href="http://www.opengeospatial.org/standards/kml/">OGC KML (Keyhole Markup Language)</a>.
   */
  public static final MediaType KML = createConstant(APPLICATION_TYPE, "vnd.google-earth.kml+xml");

  /**
   * <a href="http://www.opengeospatial.org/standards/kml/">OGC KML (Keyhole Markup Language)</a>,
   * compressed using the ZIP format into KMZ archives.
   */