This is different from using an `APIRouter` as a mounted application is completely independent. The OpenAPI and docs from your main application won't include anything from the mounted application, etc.

You can read more about this in the [Advanced User Guide](../advanced/index.md){.internal-link target=_blank}.

## Details { #details }

This sub-application is just another standard FastAPI application, but this is the one that will be "mounted":

{* ../../docs_src/sub_applications/tutorial001_py39.py hl[11, 14:16] *}

### Mount the sub-application { #mount-the-sub-application }

In your top-level application, `app`, mount the sub-application, `subapi`.

In this case, it will be mounted at the path `/subapi`:

{* ../../docs_src/sub_applications/tutorial001_py39.py hl[11, 19] *}

TFCI_WHL_IMPORT_TEST_ENABLE=1
TFCI_PYTHON_VERIFY_PIP_INSTALL_ARGS=""

# Used to simulate a T:\ drive within the container, to a limited extent,
# via a symlink.
# Helpful since the internal CI utilizes a T:\ drive, part of which is mounted
# to the container, and would result in C:\<path> != T:\<path> mismatches,
# when using variables like `TFCI_OUTPUT_DIR` in `docker exec commands,
# requiring conditional path adjustments throughout the CI scripts.

```html
<a href="/items/42">
```

## Templates and static files { #templates-and-static-files }

You can also use `url_for()` inside of the template, and use it, for example, with the `StaticFiles` you mounted with the `name="static"`.

```jinja hl_lines="4"
{!../../docs_src/templates/templates/item.html!}
```

In this example, it would link to a CSS file at `static/styles.css` with:

```CSS hl_lines="4"

* «the lock»: «der Lock»
* «the locking»: «das Locking»
* «the mobile application»: «die Mobile-Anwendung»
* «the model object»: «das Modellobjekt»
* «the mounting»: «das Mounten»
* «mounted»: «gemountet»
* «the origin»: «das Origin»
* «the override»: «Die Überschreibung»
* «the parameter»: «der Parameter»
* «the parameters» (plural): «die Parameter»

**Note**: this is a very technical detail that you probably can **just skip**.

---

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.

///

# Unteranwendungen – Mounts { #sub-applications-mounts }

Wenn Sie zwei unabhängige FastAPI-Anwendungen mit deren eigenen unabhängigen OpenAPI und deren eigenen Dokumentationsoberflächen benötigen, können Sie eine Hauptanwendung haben und dann eine (oder mehrere) Unteranwendung(en) „mounten“.

## Eine **FastAPI**-Anwendung mounten { #mounting-a-fastapi-application }

            _extract_endpoint_context(dependant.call)
            if dependant.call
            else EndpointContext()
        )

        if dependant.path:
            # For mounted sub-apps, include the mount path prefix
            mount_path = request.scope.get("root_path", "").rstrip("/")
            endpoint_ctx["path"] = f"{request.method} {mount_path}{dependant.path}"

        # Read body and auto-close files

Essa sub-aplicação é apenas outra aplicação FastAPI padrão, mas esta é a que será "montada":

{* ../../docs_src/sub_applications/tutorial001_py39.py hl[11, 14:16] *}

### Monte a sub-aplicação { #mount-the-sub-application }

Na sua aplicação de nível superior, `app`, monte a sub-aplicação, `subapi`.

Neste caso, ela será montada no path `/subapi`:

{* ../../docs_src/sub_applications/tutorial001_py39.py hl[11, 19] *}

# WSGI inkludieren – Flask, Django und andere { #including-wsgi-flask-django-others }

Sie können WSGI-Anwendungen mounten, wie Sie es in [Unteranwendungen – Mounts](sub-applications.md){.internal-link target=_blank}, [Hinter einem Proxy](behind-a-proxy.md){.internal-link target=_blank} gesehen haben.

Dazu können Sie die `WSGIMiddleware` verwenden und damit Ihre WSGI-Anwendung wrappen, zum Beispiel Flask, Django usw.

## `WSGIMiddleware` verwenden { #using-wsgimiddleware }