* **Facile**: Progettato per essere facile da usare e imparare. Si riduce il tempo da dedicare alla lettura della documentazione.
* **Sintentico**: Minimizza la duplicazione di codice. Molteplici funzionalità, ognuna con la propria dichiarazione dei parametri. Meno errori.
* **Robusto**: Crea codice pronto per la produzione con documentazione automatica interattiva.

    On voit bien dans la documentation que `item_id` est déclaré comme entier.

## Les avantages d'avoir une documentation basée sur une norme, et la documentation alternative.

    * 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).

It was one of the first examples of **automatic API documentation**, and this was specifically one of the first ideas that inspired "the search for" **FastAPI**.

!!! note
    Django REST Framework was created by Tom Christie. The same creator of Starlette and Uvicorn, on which **FastAPI** is based.


!!! check "Inspired **FastAPI** to"
    Have an automatic API documentation web user interface.

    This is incredibly helpful while developing and debugging code that interacts with your API.

## Documentation

And when you open your browser at <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>, you will see an automatic, interactive, API documentation like:

<img src="/img/tutorial/path-params/image01.png">

!!! check

And those Python files are included/injected in the documentation when generating the site.

### Docs for tests

Most of the tests actually run against the example source files in the documentation.

This helps to make sure that:

* The documentation is up-to-date.
* The documentation examples can be run as is.
* Most of the features are covered by the documentation, ensured by test coverage.

On utilise alors l'argument `deprecated=True` de `Query` :

```Python hl_lines="18"
{!../../../docs_src/query_params_str_validations/tutorial010.py!}
```

La documentation le présentera comme il suit :

And of course, it supports the same:

* data validation
* data serialization
* data documentation, etc.

This works the same way as with Pydantic models. And it is actually achieved in the same way underneath, using Pydantic.

!!! info
    Keep in mind that dataclasses can't do everything Pydantic models can do.

```Python hl_lines="3  22  25-26"
{!../../../docs_src/graphql/tutorial001.py!}
```

You can learn more about Strawberry in the <a href="https://strawberry.rocks/" class="external-link" target="_blank">Strawberry documentation</a>.

And also the docs about <a href="https://strawberry.rocks/docs/integrations/fastapi" class="external-link" target="_blank">Strawberry with FastAPI</a>.

## Older `GraphQLApp` from Starlette

FastAPI will use this `response_model` to do all the data documentation, validation, etc. and also to **convert and filter the output data** to its type declaration.

!!! tip
    If you have strict type checks in your editor, mypy, etc, you can declare the function return type as `Any`.

    That way you tell the editor that you are intentionally returning anything. But FastAPI will still do the data documentation, validation, filtering, etc. with the `response_model`.