This provider might be charging you per request, and calling it might take some extra time than if you had a fixed mock user for tests.

You probably want to test the external provider once, but not necessarily call it for every test that runs.

In this case, you can override the dependency that calls that provider, and use a custom dependency that returns a mock user, only for your tests.

### Use the `app.dependency_overrides` attribute

        use_sub_dependant = sub_dependant
        if (
            dependency_overrides_provider
            and dependency_overrides_provider.dependency_overrides
        ):
            original_call = sub_dependant.call
            call = getattr(
                dependency_overrides_provider, "dependency_overrides", {}
            ).get(original_call, original_call)

{!../../../docs_src/custom_docs_ui/tutorial001.py!}
```

!!! tip
    The *path operation* for `swagger_ui_redirect` is a helper for when you use OAuth2.

    If you integrate your API with an OAuth2 provider, you will be able to authenticate and come back to the API docs with the acquired credentials. And interact with it using the real OAuth2 authentication.

!!! tip
    Integrating other authentication/authorization providers like Google, Facebook, Twitter, GitHub, etc. is also possible and relatively easy.

    The most complex problem is building an authentication/authorization provider like those, but **FastAPI** gives you the tools to do it easily, while doing the heavy lifting for you.

## **FastAPI** utilities

                solved_result = await solve_dependencies(
                    request=request,
                    dependant=dependant,
                    body=body,
                    dependency_overrides_provider=dependency_overrides_provider,
                    async_exit_stack=async_exit_stack,
                )
                values, errors, background_tasks, sub_response, _ = solved_result
                if not errors:

# Deploy FastAPI on Cloud Providers

You can use virtually **any cloud provider** to deploy your FastAPI application.

In most of the cases, the main cloud providers have guides to deploy FastAPI with them.

## Cloud Providers - Sponsors

Some cloud providers ✨ [**sponsor FastAPI**](../help-fastapi.md#sponsor-the-author){.internal-link target=_blank} ✨, this ensures the continued and healthy **development** of FastAPI and its **ecosystem**.

* Ein sehr leistungsfähiges und einfach zu bedienendes System für **<abbr title="Dependency Injection – Einbringen von Abhängigkeiten: Auch bekannt als Komponenten, Ressourcen, Provider, Services, Injectables">Dependency Injection</abbr>**.
* Sicherheit und Authentifizierung, einschließlich Unterstützung für **OAuth2** mit **JWT-Tokens** und **HTTP-Basic**-Authentifizierung.

The most common is the implicit flow.

The most secure is the code flow, but is more complex to implement as it requires more steps. As it is more complex, many providers end up suggesting the implicit flow.

!!! note

  - author: Nils de Bruin
    author_link: https://medium.com/@nilsdebruin
    link: https://medium.com/data-rebels/fastapi-google-as-an-external-authentication-provider-3a527672cf33
    title: FastAPI — Google as an external authentication provider
  - author: William Hayes
    author_link: https://medium.com/@williamhayes
    link: https://medium.com/@williamhayes/fastapi-starlette-debug-vs-prod-5f7561db3a59

* **Modify some DNS records**.
    * For this, the renewal program needs to support the APIs of the DNS provider, so, depending on the DNS provider you are using, this might or might not be an option.
* **Run as a server** (at least during the certificate acquisition process) on the public IP address associated with the domain.