# Behind a Proxy

In some situations, you might need to use a **proxy** server like Traefik or Nginx with a configuration that adds an extra path prefix that is not seen by your application.

In these cases you can use `root_path` to configure your application.

The `root_path` is a mechanism provided by the ASGI specification (that FastAPI is built on, through Starlette).

The `root_path` is used to handle these specific cases.

"docs_src/dependencies/tutorial010.py" = ["F821"]
"docs_src/custom_response/tutorial007.py" = ["B007"]
"docs_src/dataclasses/tutorial003.py" = ["I001"]
"docs_src/path_operation_advanced_configuration/tutorial007.py" = ["B904"]
"docs_src/path_operation_advanced_configuration/tutorial007_pv1.py" = ["B904"]
"docs_src/custom_request_and_route/tutorial002.py" = ["B904"]
"docs_src/dependencies/tutorial008_an.py" = ["F821"]

* ✨ Add support for tags with Enums. PR [#4468](https://github.com/tiangolo/fastapi/pull/4468) by [@tiangolo](https://github.com/tiangolo). New docs: [Path Operation Configuration - Tags with Enums](https://fastapi.tiangolo.com/tutorial/path-operation-configuration/#tags-with-enums).

    - tutorial/response-status-code.md
    - tutorial/request-forms.md
    - tutorial/request-files.md
    - tutorial/request-forms-and-files.md
    - tutorial/handling-errors.md
    - tutorial/path-operation-configuration.md
    - tutorial/encoder.md
    - tutorial/body-updates.md
    - Dependencies:
      - tutorial/dependencies/index.md
      - tutorial/dependencies/classes-as-dependencies.md

    ```

    !!! tip
        The `Config` class is used just for Pydantic configuration. You can read more at <a href="https://docs.pydantic.dev/1.10/usage/model_config/" class="external-link" target="_blank">Pydantic Model Config</a>.

!!! info

* <a href="https://jinja.palletsprojects.com" target="_blank"><code>jinja2</code></a> - Obligatoire si vous souhaitez utiliser la configuration de template par défaut.

* <a href="https://jinja.palletsprojects.com" target="_blank"><code>jinja2</code></a> - Required if you want to use the default template configuration.

* <a href="https://jinja.palletsprojects.com" target="_blank"><code>jinja2</code></a> - Required if you want to use the default template configuration.

It has **sensible defaults**, but you can still change and update all the configurations with **environment variables** or configuration files.

It also supports running <a href="https://github.com/tiangolo/uvicorn-gunicorn-fastapi-docker#pre_start_path" class="external-link" target="_blank">**previous steps before starting**</a> with a script.

!!! tip

No more typing the wrong key names, coming back and forth between docs, or scrolling up and down to find if you finally used `username` or `user_name`.

### Short

It has sensible **defaults** for everything, with optional configurations everywhere. All the parameters can be fine-tuned to do what you need and to define the API you need.

But by default, it all **"just works"**.

### Validation