You will see the automatic API docs for the main app, including only its own _path operations_:

<img src="/img/tutorial/sub-applications/image01.png">

And then, open the docs for the sub-application, at <a href="http://127.0.0.1:8000/subapi/docs" class="external-link" target="_blank">http://127.0.0.1:8000/subapi/docs</a>.

```Python
{
    "id": 1,
    "text": "Some note",
    "completed": False,
}
```

## Check it

You can copy this code as is, and see the docs at <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

There you can see all your API documented and interact with it:

<img src="/img/tutorial/async-sql-databases/image01.png">

## More info

If you want to play with JWT tokens and see how they work, check <a href="https://jwt.io/" class="external-link" target="_blank">https://jwt.io</a>.

## Install `python-jose`

We need to install `python-jose` to generate and verify the JWT tokens in Python:

Let's use the tools provided by **FastAPI** to handle security.

## How it looks

Let's first just use the code and see how it works, and then we'll come back to understand what's happening.

## Create `main.py`

Copy the example in a file `main.py`:

=== "Python 3.9+"

    ```Python

This might all sound abstract. Don't worry. You'll see all this in action in the [Tutorial - User Guide](tutorial/index.md){.internal-link target=_blank}.

The important thing is that by using standard Python types, in a single place (instead of adding more classes, decorators, etc), **FastAPI** will do a lot of the work for you.

!!! info

If you check out the "task manager" or "system monitor" (or similar tools) in your operating system, you will be able to see many of those processes running.

And, for example, you will probably see that there are multiple processes running the same browser program (Firefox, Chrome, Edge, etc). They normally run one process per tab, plus some other extra processes.

# Body - Multiple Parameters

Now that we have seen how to use `Path` and `Query`, let's see more advanced uses of request body declarations.

## Mix `Path`, `Query` and body parameters

First, of course, you can mix `Path`, `Query` and request body parameter declarations freely and **FastAPI** will know what to do.

And you can also declare body parameters as optional, by setting the default to `None`:

=== "Python 3.10+"

!!! tip
    You could become an official FastAPI Expert too!

    Just [help others with questions in GitHub](help-fastapi.md#help-others-with-questions-in-github){.internal-link target=_blank}. 🤓

You can see the **FastAPI Experts** for:

* [Last Month](#fastapi-experts-last-month) 🤓
* [3 Months](#fastapi-experts-3-months) 😎
* [6 Months](#fastapi-experts-6-months) 🧐
* [1 Year](#fastapi-experts-1-year) 🧑‍🔬

We are going to include this `APIRouter` in the main `FastAPI` app, but first, let's check the dependencies and another `APIRouter`.

## Dependencies

We see that we are going to need some dependencies used in several places of the application.

So we put them in their own `dependencies` module (`app/dependencies.py`).

* Decompressing gzip-compressed request bodies.
* Automatically logging all request bodies.

## Handling custom request body encodings

Let's see how to make use of a custom `Request` subclass to decompress gzip requests.

And an `APIRoute` subclass to use that custom request class.

### Create a custom `GzipRequest` class

!!! tip