* The _path_ `/items/{item_id}` has an optional `str` _query parameter_ `q`.

### Interactive API docs { #interactive-api-docs }

Now go to [http://127.0.0.1:8000/docs](http://127.0.0.1:8000/docs).

You will see the automatic interactive API documentation (provided by [Swagger UI](https://github.com/swagger-api/swagger-ui)):

* Le _chemin_ `/items/{item_id}` a un _paramètre de requête_ optionnel `q` de type `str`.

### Documentation API interactive { #interactive-api-docs }

Maintenant, rendez-vous sur [http://127.0.0.1:8000/docs](http://127.0.0.1:8000/docs).

Vous verrez la documentation interactive automatique de l'API (fournie par [Swagger UI](https://github.com/swagger-api/swagger-ui)) :

* The _path_ `/items/{item_id}` has an optional `str` _query parameter_ `q`.

### Interactive API docs

Now go to [http://127.0.0.1:8000/docs](http://127.0.0.1:8000/docs).

You will see the automatic interactive API documentation (provided by [Swagger UI](https://github.com/swagger-api/swagger-ui)):

{* ../../docs_src/path_operation_configuration/tutorial004_py310.py hl[17:25] *}

It will be used in the interactive docs:

<img src="/img/tutorial/path-operation-configuration/image02.png">

## Response description { #response-description }

You can specify the response description with the parameter `response_description`:

```console
$ fastapi dev

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

## Check it { #check-it }

Go to the interactive docs at: [http://127.0.0.1:8000/docs](http://127.0.0.1:8000/docs).

You will see something like this:

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

/// check | Authorize button!

You will see the JSON response as:

```JSON
{"message": "Hello World"}
```

### Interactive API docs { #interactive-api-docs }

Now go to [http://127.0.0.1:8000/docs](http://127.0.0.1:8000/docs).

You will see the automatic interactive API documentation (provided by [Swagger UI](https://github.com/swagger-api/swagger-ui)):

And when you open your browser at [http://127.0.0.1:8000/docs](http://127.0.0.1:8000/docs), you will see an automatic, interactive, API documentation like:

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

/// check

Again, just with that same Python type declaration, **FastAPI** gives you automatic, interactive documentation (integrating Swagger UI).

Notice that the path parameter is declared to be an integer.

///

Vous verrez la réponse JSON suivante :

```JSON
{"message": "Hello World"}
```

### Documentation interactive de l’API { #interactive-api-docs }

Allez maintenant sur [http://127.0.0.1:8000/docs](http://127.0.0.1:8000/docs).

Vous verrez la documentation interactive de l’API générée automatiquement (fournie par [Swagger UI](https://github.com/swagger-api/swagger-ui)) :

### Automatic docs { #automatic-docs }

Interactive API documentation and exploration web user interfaces. As the framework is based on OpenAPI, there are multiple options, 2 included by default.

* [**Swagger UI**](https://github.com/swagger-api/swagger-ui), with interactive exploration, call and test your API directly from the browser.

![Swagger UI interaction](https://fastapi.tiangolo.com/img/index/index-03-swagger-02.png)

/// warning

A `Response` returned directly by your *path operation function* won't be documented in OpenAPI (for example, the `Content-Type` won't be documented) and won't be visible in the automatic interactive docs.

///

/// info

Of course, the actual `Content-Type` header, status code, etc, will come from the `Response` object you returned.

///