<img src="/img/tutorial/security/image02.png">

!!! note
    It doesn't matter what you type in the form, it won't work yet. But we'll get there.

This is of course not the frontend for the final users, but it's a great automatic tool to document interactively all your API.

It can be used by the frontend team (that can also be yourself).

    {!> ../../../docs_src/dependencies/tutorial006.py!}
    ```

### Return values

And they can return values or not, the values won't be used.

So, you can re-use a normal dependency (that returns a value) you already use somewhere else, and even though the value won't be used, the dependency will be executed:

=== "Python 3.9+"

    ```Python hl_lines="11  16"

!!! check
    You don't have to worry about performance when including routers.

    This will take microseconds and will only happen at startup.

    So it won't affect performance. ⚡

### Include an `APIRouter` with a custom `prefix`, `tags`, `responses`, and `dependencies`

Now, let's imagine your organization gave you the `app/internal/admin.py` file.

                            dataValue["delay"] = 0;
                        }
                        if (buffer[buffer.length - 1] === "") {
                            // A last single <br> won't have effect
                            // so put an additional one
                            buffer.push("");
                        }
                        const bufferValue = buffer.join("<br>");

!!! tip
    `JSONResponse` itself is a sub-class of `Response`.

And when you return a `Response`, **FastAPI** will pass it directly.

It won't do any data conversion with Pydantic models, it won't convert the contents to any type, etc.

This gives you a lot of flexibility. You can return any data type, override any data declaration or validation, etc.

```Python hl_lines="2  7  19"
{!../../../docs_src/custom_response/tutorial003.py!}
```

!!! warning
    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.

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="7"
    {!> ../../../docs_src/dependencies/tutorial011.py!}
    ```

In this case, **FastAPI** won't ever touch or care about `__init__`, we will use it directly in our code.

## Create an instance

We could create an instance of this class with:

=== "Python 3.9+"

    ```Python hl_lines="18"

    * Only applications using forms (e.g. file uploads) could be affected.
    * For most cases, upgrading won't have any breaking changes.

## 0.91.0

### Upgrades

    ```Python hl_lines="7"
    {!> ../../../docs_src/path_params_numeric_validations/tutorial002.py!}
    ```

But keep in mind that if you use `Annotated`, you won't have this problem, it won't matter as you're not using the function parameter default values for `Query()` or `Path()`.

=== "Python 3.9+"

    ```Python hl_lines="10"

    {!> ../../../docs_src/additional_status_codes/tutorial001.py!}
    ```

!!! warning
    When you return a `Response` directly, like in the example above, it will be returned directly.

    It won't be serialized with a model, etc.

    Make sure it has the data you want it to have, and that the values are valid JSON (if you are using `JSONResponse`).

!!! note "Technical Details"