!!! tip
    As FastAPI is an async framework, one request could start being processed, and before finishing, another request could be received and start processing as well, and it all could be processed in the same thread.

!!! check
    Bei der Einbindung von Routern müssen Sie sich keine Gedanken über die Performanz machen.

    Dies dauert Mikrosekunden und geschieht nur beim Start.

    Es hat also keinen Einfluss auf die Leistung. ⚡

### Einen `APIRouter` mit benutzerdefinierten `prefix`, `tags`, `responses` und `dependencies` einfügen

## Coroutines

**Coroutine** is just the very fancy term for the thing returned by an `async def` function. Python knows that it is something like a function that it can start and that it will end at some point, but that it might be paused ⏸ internally too, whenever there is an `await` inside of it.

The command `fastapi dev` reads your `main.py` file, detects the **FastAPI** app in it, and starts a server using <a href="https://www.uvicorn.org" class="external-link" target="_blank">Uvicorn</a>.

By default, `fastapi dev` will start with auto-reload enabled for local development.

You can read more about it in the <a href="https://fastapi.tiangolo.com/fastapi-cli/" target="_blank">FastAPI CLI docs</a>.

</details>

### Check it

    frontmatter_end = match_pre.end()
    pre_end = match_start.end()
    post_start = match_end.start()
    template = Template(index_sponsors_template)
    message = template.render(sponsors=sponsors)
    pre_content = content[frontmatter_end:pre_end]
    post_content = content[post_start:]
    new_content = pre_content + message + post_content
    return new_content

Einige wichtige Konzepte sind:

* Sicherheit – HTTPS
* Beim Hochfahren ausführen
* Neustarts
* Replikation (die Anzahl der laufenden Prozesse)
* Arbeitsspeicher
* Schritte vor dem Start

Wir werden sehen, wie diese sich auf das **Deployment** auswirken.

<div class="termy">

```console
$ python ./scripts/docs.py live

<span style="color: green;">[INFO]</span> Serving on http://127.0.0.1:8008
<span style="color: green;">[INFO]</span> Start watching changes
<span style="color: green;">[INFO]</span> Start detecting changes
```

</div>

ドキュメントは、`http://127.0.0.1:8008`で提供します。

そうすることで、ドキュメント/ソースファイルを編集し、変更をライブで見ることができます。

#### Typer CLI (任意)

participant dep as Dep with yield
participant operation as Path Operation
participant tasks as Background tasks

    Note over client,operation: Can raise exceptions, including HTTPException
    client ->> dep: Start request
    Note over dep: Run code up to yield
    opt raise Exception
        dep -->> handler: Raise Exception
        handler -->> client: HTTP error response
    end

The command `fastapi dev` reads your `main.py` file, detects the **FastAPI** app in it, and starts a server using <a href="https://www.uvicorn.org" class="external-link" target="_blank">Uvicorn</a>.

By default, `fastapi dev` will start with auto-reload enabled for local development.

You can read more about it in the <a href="https://fastapi.tiangolo.com/fastapi-cli/" target="_blank">FastAPI CLI docs</a>.

</details>

### Check it

                    results.append(result)  # noqa: B023

                async with anyio.create_task_group() as tg:
                    for sub_value in value:
                        tg.start_soon(process_fn, sub_value.read)
                value = serialize_sequence_value(field=field, value=results)

            v_, errors_ = field.validate(value, values, loc=loc)

            if isinstance(errors_, list):