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):

For example, in Visual Studio Code, you can:

* Go to the "Debug" panel.
* "Add configuration...".
* Select "Python"
* Run the debugger with the option "`Python: Current File (Integrated Terminal)`".

It will then start the server with your **FastAPI** code, stop at your breakpoints, etc.

Here's how it might look:

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

---

If you use Pycharm, you can:

But Gunicorn supports working as a **process manager** and allowing users to tell it which specific **worker process class** to use. Then Gunicorn would start one or more **worker processes** using that class.

And **Uvicorn** has a **Gunicorn-compatible worker class**.

<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>

Он запустит сайт документации по адресу: `http://127.0.0.1:8008`.

👉 🖼 ✔️ **🚘-📳** 🛠️ 🔌 ⚒ **🔢 👨‍🏭 🛠️** ⚓️ 🔛 💽 🐚 💪.

⚫️ ✔️ **🤔 🔢**, ✋️ 👆 💪 🔀 & ℹ 🌐 📳 ⏮️ **🌐 🔢** ⚖️ 📳 📁.

⚫️ 🐕‍🦺 🏃 <a href="https://github.com/tiangolo/uvicorn-gunicorn-fastapi-docker#pre_start_path" class="external-link" target="_blank">**⏮️ 🔁 ⏭ ▶️**</a> ⏮️ ✍.

!!! tip

Es unterstützt auch die Ausführung von <a href="https://github.com/tiangolo/uvicorn-gunicorn-fastapi-docker#pre_start_path" class="external-link" target="_blank">**Vorab-Schritten vor dem Start** </a> mit einem Skript.

!!! tip "Tipp"

このイメージには、利用可能なCPUコアに基づいて**ワーカー・プロセスの数**を設定する**オートチューニング**メカニズムが含まれています。

これは**賢明なデフォルト**を備えていますが、**環境変数**や設定ファイルを使ってすべての設定を変更したり更新したりすることができます。

また、スクリプトで<a href="https://github.com/tiangolo/uvicorn-gunicorn-fastapi-docker#pre_start_path" class="external-link" target="_blank">**開始前の事前ステップ**</a>を実行することもサポートしている。

!!! tip

A container is running as long as the **main process** (command or program) is running.

A container normally has a **single process**, but it's also possible to start subprocesses from the main process, and that way you will have **multiple processes** in the same container.

            a custom encoder.
            """
        ),
    ] = None,
    sqlalchemy_safe: Annotated[
        bool,
        Doc(
            """
            Exclude from the output any fields that start with the name `_sa`.

            This is mainly a hack for compatibility with SQLAlchemy objects, they
            store internal SQLAlchemy-specific state in attributes named with `_sa`,