ines-course.jpg...

fastapi-course-bundle-banner.png...

fastapi-course-bundle-banner.svg...

## Running on Startup

In most cases, when you create a web API, you want it to be **always running**, uninterrupted, so that your clients can always access it. This is of course, unless you have a specific reason why you want it to run only in certain situations, but most of the time you want it constantly running and **available**.

### In a Remote Server

We get the same response:

```JSON
{
    "message": "Hello World",
    "root_path": "/api/v1"
}
```

but this time at the URL with the prefix path provided by the proxy: `/api/v1`.

Of course, the idea here is that everyone would access the app through the proxy, so the version with the path prefix `/api/v1` is the "correct" one.

    A `Response` returned directly by your *path operation function* won't be documented in OpenAPI (for example, the `Content-Type` won't be documented) and won't be visible in the automatic interactive docs.

!!! info
    Of course, the actual `Content-Type` header, status code, etc, will come from the `Response` object you returned.

### Document in OpenAPI and override `Response`

### Example in the docs UI

With any of the methods above it would look like this in the `/docs`:

<img src="/img/tutorial/body-fields/image01.png">

### `Body` with multiple `examples`

You can of course also pass multiple `examples`:

=== "Python 3.10+"

    ```Python hl_lines="23-38"
    {!> ../../../docs_src/schema_extra_example/tutorial004_an_py310.py!}
    ```

=== "Python 3.9+"

### Using your local FastAPI

If you create a Python file that imports and uses FastAPI, and run it with the Python from your local environment, it will use your cloned local FastAPI source code.

And if you update that local FastAPI source code when you run that Python file again, it will use the fresh version of FastAPI you just edited.

That way, you don't have to "install" your local version to be able to test every change.

It would depend mainly on the tool you use to **install** those requirements.

The most common way to do it is to have a file `requirements.txt` with the package names and their versions, one per line.

You would of course use the same ideas you read in [About FastAPI versions](versions.md){.internal-link target=_blank} to set the ranges of versions.

For example, your `requirements.txt` could look like:

```
fastapi>=0.112.0,<0.113.0

$ python -m venv env
```

</div>

👈 🔜 ✍ 📁 `./env/` ⏮️ 🐍 💱 &amp; ⤴️ 👆 🔜 💪 ❎ 📦 👈 ❎ 🌐.

### 🔓 🌐

🔓 🆕 🌐 ⏮️:

=== "💾, 🇸🇻"

    <div class="termy">

    ```console
    $ source ./env/bin/activate
    ```

    </div>

=== "🚪 📋"

    <div class="termy">

    ```console
    $ .\env\Scripts\Activate.ps1
    ```

    </div>

=== "🚪 🎉"