# 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+"

Given the simplicity of Flask, it seemed like a good match for building APIs. The next thing to find was a "Django REST Framework" for Flask.

!!! check "Inspired **FastAPI** to"
    Be a micro-framework. Making it easy to mix and match the tools and parts needed.

    Have a simple and easy to use routing system.


### <a href="https://requests.readthedocs.io" class="external-link" target="_blank">Requests</a>

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If your application (somehow) doesn't have to communicate with anything else and wait for it to respond, use `async def`.

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If you just don't know, use normal `def`.

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**Note**: You can mix `def` and `async def` in your *path operation functions* as much as you need and define each one using the best option for you. FastAPI will do the right thing with them.

Чтобы это понять, представьте такую картину:

### Конкурентные бургеры

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Вы идёте со своей возлюбленной 😍 в фастфуд 🍔 и становитесь в очередь, в это время кассир 💁 принимает заказы у посетителей перед вами.