In this case, the original path `/app` would actually be served at `/api/v1/app`.

Even though all your code is written assuming there's just `/app`.

```Python hl_lines="6"
{!../../../docs_src/behind_a_proxy/tutorial001.py!}
```

* 🌐 Add Korean translation for Tutorial - First Steps. PR [#2323](https://github.com/tiangolo/fastapi/pull/2323) by [@hard-coders](https://github.com/hard-coders).
* 🌐 Add Chinese translation for Tutorial - CORS (Cross-Origin Resource Sharing). PR [#2540](https://github.com/tiangolo/fastapi/pull/2540) by [@blt232018](https://github.com/blt232018).

* D'obtenir de nombreuses fonctionnalités supplémentaires (grâce à  Starlette) comme :
    * **WebSockets**
    * de tester le code très facilement avec `requests` et `pytest`
    * **<abbr title="Cross-Origin Resource Sharing">CORS</abbr>**
    * **Cookie Sessions**
    * ... et plus encore.

## Performance

### The callback path expression

The callback *path* can have an <a href="https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.1.0.md#key-expression" class="external-link" target="_blank">OpenAPI 3 expression</a> that can contain parts of the original request sent to *your API*.

In this case, it's the `str`:

</a>
</p>

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**Àkọsílẹ̀**: <a href="https://fastapi.tiangolo.com" target="_blank">https://fastapi.tiangolo.com</a>

**Orisun Kóòdù**: <a href="https://github.com/tiangolo/fastapi" target="_blank">https://github.com/tiangolo/fastapi</a>

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