And it shows their true commitment to FastAPI and its **community** (you), as they not only want to provide you a **good service** but also want to make sure you have a **good and healthy framework**, FastAPI. 🙇

For example, you might want to try <a href="https://speakeasyapi.dev/?utm_source=fastapi+repo&utm_medium=github+sponsorship" class="external-link" target="_blank">Speakeasy</a>.

### FastAPI Data Filtering

Now, for FastAPI, it will see the return type and make sure that what you return includes **only** the fields that are declared in the type.

FastAPI does several things internally with Pydantic to make sure that those same rules of class inheritance are not used for the returned data filtering, otherwise you could end up returning much more data than what you expected.

Another big feature needed by APIs is data validation, making sure that the data is valid, given certain parameters. For example, that some field is an `int`, and not some random string. This is especially useful for incoming data.

Au final, peu importe le cas parmi ceux ci-dessus, **FastAPI** fonctionnera de manière asynchrone et sera extrêmement rapide.

Mais si vous suivez bien les instructions ci-dessus, alors **FastAPI** pourra effectuer quelques optimisations et ainsi améliorer les performances.

## Détails techniques

### Separate Program

To achieve this, you will normally have a **separate program** that would make sure your application is run on startup. And in many cases, it would also make sure other components or applications are also run, for example, a database.

### Example Tools to Run at Startup

Some examples of the tools that can do this job are:

* Docker

Usado por FastAPI / Starlette:

* <a href="https://www.uvicorn.org" target="_blank"><code>uvicorn</code></a> - para el servidor que carga y sirve tu aplicación.
* <a href="https://github.com/ijl/orjson" target="_blank"><code>orjson</code></a> - Requerido si quieres usar `ORJSONResponse`.

The same way you can include an `APIRouter` in a `FastAPI` application, you can include an `APIRouter` in another `APIRouter` using:

```Python
router.include_router(other_router)
```

    * Make sure you add your link to the start of the corresponding section.
* To help [translate the documentation](contributing.md#translations){.internal-link target=_blank} to your language.
    * You can also help to review the translations created by others.
* To propose new documentation sections.
* To fix an existing issue/bug.
    * Make sure to add tests.
* To add a new feature.

!!! info
    FastAPI added support for `Annotated` (and started recommending it) in version 0.95.0.

    If you have an older version, you would get errors when trying to use `Annotated`.

    Make sure you [Upgrade the FastAPI version](../../deployment/versions.md#upgrading-the-fastapi-versions){.internal-link target=_blank} to at least 0.95.1 before using `Annotated`.

### Import `Depends`

=== "Python 3.10+"

## What is "Form Data"

The way HTML forms (`<form></form>`) sends the data to the server normally uses a "special" encoding for that data, it's different from JSON.

**FastAPI** will make sure to read that data from the right place instead of JSON.

!!! note "Technical Details"
    Data from forms is normally encoded using the "media type" `application/x-www-form-urlencoded` when it doesn't include files.