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>.

### Authenticate { #authenticate }

Click the "Authorize" button.

Use the credentials:

    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA

Also add information on how to contact you by electronic and paper mail.

If the program is interactive, make it output a short notice like this
when it starts in an interactive mode:

    Gnomovision version 69, Copyright (C) year name of author
    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type

///

## Déclarer des métadonnées supplémentaires

On peut aussi ajouter plus d'informations sur le paramètre.

Ces informations seront incluses dans le schéma `OpenAPI` généré et utilisées par la documentation interactive ou les outils externes utilisés.

/// note

Gardez en tête que les outils externes utilisés ne supportent pas forcément tous parfaitement OpenAPI.

    * Générant automatiquement des **erreurs** renvoyées au client quand la donnée est invalide.
* **Documenter** l'API avec OpenAPI :
    * ce qui ensuite utilisé par les interfaces utilisateur automatiques de documentation interactive.

Tout cela peut paraître bien abstrait, mais ne vous inquiétez pas, vous verrez tout ça en pratique dans [Tutoriel - Guide utilisateur](tutorial/index.md){.internal-link target=_blank}.

}
```

/// tip

To declare a query parameter with a type of `list`, like in the example above, you need to explicitly use `Query`, otherwise it would be interpreted as a request body.

///

The interactive API docs will update accordingly, to allow multiple values:

<img src="/img/tutorial/query-params-str-validations/image02.png">

When you see the automatic docs, you can check that the input model and output model will both have their own JSON Schema:

<img src="/img/tutorial/response-model/image01.png">

And both models will be used for the interactive API documentation:

<img src="/img/tutorial/response-model/image02.png">

## Other Return Type Annotations { #other-return-type-annotations }

* **Validate data**: coming from each request:
    * 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}.

                        user = auth.getUserName();
                        password = new String(auth.getPassword());
                    } catch (final Exception ex) {
                        log.debug("Interactive authentication failed", ex);
                    }
                }
                final Type2Message type2 = (Type2Message) message;

* `/items/`
* `/items/{item_id}`

...as we intended.

* They will be marked with a list of tags that contain a single string `"items"`.
    * These "tags" are especially useful for the automatic interactive documentation systems (using OpenAPI).
* All of them will include the predefined `responses`.
* All these *path operations* will have the list of `dependencies` evaluated/executed before them.

![Swagger UI interaction](https://fastapi.tiangolo.com/img/index/index-04-swagger-03.png)

* سپس روی دکمه "Execute" کلیک کنید، خواهید دید که واسط کاربری با APIهای تعریف شده ارتباط برقرار کرده، پارامترهای مورد نیاز را به آن‌ها ارسال می‌کند، سپس نتایج را دریافت کرده و در صفحه نشان می‌دهد:

![Swagger UI interaction](https://fastapi.tiangolo.com/img/index/index-05-swagger-04.png)