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

## More info

To learn more about the options, check Starlette's documentation for:

* <a href="https://www.starlette.io/websockets/" class="external-link" target="_blank">The `WebSocket` class</a>.

    The actual callback is just an HTTP request.

    When implementing the callback yourself, you could use something like <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a> or <a href="https://requests.readthedocs.io/" class="external-link" target="_blank">Requests</a>.

## Write the callback documentation code

This code won't be executed in your app, we only need it to *document* how that *external API* should look like.

        daemon --> worker2

        worker3["Worker process"]
        daemon --> worker3
    
```

These are all Java processes. Each process has a corresponding "runtime".
All source code in Gradle is written to target one or more of these runtimes.
Most source code targets the daemon and the remaining code either targets a single runtime, for example the Gradle client, or is shared across multiple runtimes.

## Composition by architecture modules

For production you would use `fastapi run` instead. 🚀

Internally, **FastAPI CLI** uses <a href="https://www.uvicorn.org" class="external-link" target="_blank">Uvicorn</a>, a high-performance, production-ready, ASGI server. 😎

## `fastapi dev`

When you run `fastapi dev`, it will run on development mode.

### Check the docs

Now you can start your app and go to <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

You will see your docs have the normal *path operations* and now also some **webhooks**:

* <a href="https://www.uvicorn.org/" class="external-link" target="_blank">Uvicorn</a>: a high performance ASGI server.
* <a href="https://pgjones.gitlab.io/hypercorn/" class="external-link" target="_blank">Hypercorn</a>: an ASGI server compatible with HTTP/2 and Trio among other features.
* <a href="https://github.com/django/daphne" class="external-link" target="_blank">Daphne</a>: the ASGI server built for Django Channels.

# Including WSGI - Flask, Django, others

You can mount WSGI applications as you saw with [Sub Applications - Mounts](sub-applications.md){.internal-link target=_blank}, [Behind a Proxy](behind-a-proxy.md){.internal-link target=_blank}.

For that, you can use the `WSGIMiddleware` and use it to wrap your WSGI application, for example, Flask, Django, etc.

## Using `WSGIMiddleware`

You need to import `WSGIMiddleware`.