<img src="/img/tutorial/behind-a-proxy/image03.png">

!!! tip
    The docs UI will interact with the server that you select.

### Disable automatic server from `root_path`

If you don't want **FastAPI** to include an automatic server using the `root_path`, you can use the parameter `root_path_in_servers=False`:

```Python hl_lines="9"

def get_invalid_none():
    return None
```

This way the data will be correctly validated, you won't have an internal server error, and the documentation will also reflect that this *path operation* could return `None` (or `null` in JSON).

### Fixes

<a href="https://reflex.dev" target="_blank" title="Reflex"><img src="https://fastapi.tiangolo.com/img/sponsors/reflex.png"></a>

### Alternative API docs upgrade

And now, go to <a href="http://127.0.0.1:8000/redoc" class="external-link" target="_blank">http://127.0.0.1:8000/redoc</a>.

* The alternative documentation will also reflect the new query parameter and body:

![ReDoc](https://fastapi.tiangolo.com/img/index/index-06-redoc-02.png)

### Recap

In summary, you declare **once** the types of parameters, body, etc. as function parameters.

  features:
  - search.suggest
  - search.highlight
  - content.tabs.link
  - navigation.indexes
  - content.tooltips
  - navigation.path
  - content.code.annotate
  - content.code.copy
  - content.code.select
  - navigation.tabs
  icon:
    repo: fontawesome/brands/github-alt
  logo: img/icon-white.svg
  favicon: img/favicon.png
  language: en
repo_name: tiangolo/fastapi
repo_url: https://github.com/tiangolo/fastapi