* Automatic data model documentation with <a href="https://json-schema.org/" class="external-link" target="_blank"><strong>JSON Schema</strong></a> (as OpenAPI itself is based on JSON Schema).

It will have a *path operation* that will receive an `Invoice` body, and a query parameter `callback_url` that will contain the URL for the callback.

This part is pretty normal, most of the code is probably already familiar to you:

```Python hl_lines="9-13  36-53"
{!../../../docs_src/openapi_callbacks/tutorial001.py!}
```

!!! tip

    - how-to/sql-databases-peewee.md
    - how-to/async-sql-encode-databases.md
    - how-to/nosql-databases-couchbase.md
- Reference (Code API):
  - reference/index.md
  - reference/fastapi.md
  - reference/parameters.md
  - reference/status.md
  - reference/uploadfile.md
  - reference/exceptions.md
  - reference/dependencies.md
  - reference/apirouter.md
  - reference/background.md
  - reference/request.md

}

// ServeHTTP - implements http.Handler interface.
//
// When the `list` query parameter is provided (its value is ignored), the
// server lists all metrics that could be returned for the requested path.
//
// The (repeatable) `buckets` query parameter is a list of bucket names (or it
// could be a comma separated value) to return metrics with a bucket label.

</div>

Open your browser at <a href="http://127.0.0.1:8000" class="external-link" target="_blank">http://127.0.0.1:8000</a>.

There you can set:

* The "Item ID", used in the path.
* The "Token" used as a query parameter.

!!! tip
    Notice that the query `token` will be handled by a dependency.

With that you can connect the WebSocket and then send and receive messages:

<img src="/img/tutorial/websockets/image05.png">

    <module>maven-model</module>
    <module>maven-monitor</module>
    <module>maven-plugin-api</module>
    <module>maven-plugin-descriptor</module>
    <module>maven-plugin-parameter-documenter</module>
    <module>maven-plugin-registry</module>
    <module>maven-plugin-tools</module>
    <module>maven-profile</module>
    <module>maven-project</module>
    <module>maven-reporting</module>