And integrate standards-based user interface tools:

    * <a href="https://github.com/swagger-api/swagger-ui" class="external-link" target="_blank">Swagger UI</a>
    * <a href="https://github.com/Rebilly/ReDoc" class="external-link" target="_blank">ReDoc</a>

    These two were chosen for being fairly popular and stable, but doing a quick search, you could find dozens of alternative user interfaces for OpenAPI (that you can use with **FastAPI**).

    * Objetos `datetime`.
    * Objetos `UUID`.
    * Modelos de bases de datos.
    * ...y muchos más.
* Documentación automática e interactiva incluyendo 2 interfaces de usuario alternativas:
    * Swagger UI.
    * ReDoc.

---

Volviendo al ejemplo de código anterior, **FastAPI** va a:

* Validar que existe un `item_id` en el path para requests usando `GET` y `PUT`.

    ---

    The `APIRouter`s are not "mounted", they are not isolated from the rest of the application.

    This is because we want to include their *path operations* in the OpenAPI schema and the user interfaces.

    As we cannot just isolate them and "mount" them independently of the rest, the *path operations* are "cloned" (re-created), not included directly.

## Check the automatic API docs

    * Generating **automatic errors** returned to the client when the data is invalid.
* **Document** the API using OpenAPI:
    * which is then used by the automatic interactive documentation user interfaces.

This might all sound abstract. Don't worry. You'll see all this in action in the [Tutorial - User Guide](tutorial/index.md){.internal-link target=_blank}.

---

## **Typer**, o FastAPI das interfaces de linhas de comando

<a href="https://typer.tiangolo.com" target="_blank"><img src="https://typer.tiangolo.com/img/logo-margin/logo-margin-vector.svg" style="width: 20%;"></a>

---

## **Typer**, le FastAPI des <abbr title="Command Line Interface">CLI</abbr>

<a href="https://typer.tiangolo.com" target="_blank"><img src="https://typer.tiangolo.com/img/logo-margin/logo-margin-vector.svg" style="width: 20%;"></a>

* Esto también permite la **generación automática de código de cliente** para muchos lenguajes.

### Documentación automática

Documentación interactiva de la API e interfaces web de exploración. Hay múltiples opciones, dos incluidas por defecto, porque el framework está basado en OpenAPI.

    * `datetime` objects.
    * `UUID` objects.
    * Database models.
    * ...and many more.
* Automatic interactive API documentation, including 2 alternative user interfaces:
    * Swagger UI.
    * ReDoc.

---

Coming back to the previous code example, **FastAPI** will:

* Validate that there is an `item_id` in the path for `GET` and `PUT` requests.

<a href="https://typer.tiangolo.com" target="_blank"><img src="https://typer.tiangolo.com/img/logo-margin/logo-margin-vector.svg" style="width: 20%;"></a>

Se stai sviluppando un'app <abbr title="Command Line Interface (interfaccia della riga di comando)">CLI</abbr> da usare nel terminale invece che una web API, ti consigliamo <a href="https://typer.tiangolo.com/" class="external-link" target="_blank">**Typer**</a>.

* Эти схемы являются частью сгенерированной схемы OpenAPI и используются для автоматического документирования <abbr title="Пользовательских интерфейсов (User Interfaces)">UI</abbr>.

## Автоматическое документирование

Схема JSON ваших моделей будет частью сгенерированной схемы OpenAPI и будет отображена в интерактивной документации API:

<img src="/img/tutorial/body/image01.png">