You can use the same type declarations with `str`, `float`, `bool` and many other complex data types.

Several of these are explored in the next chapters of the tutorial.

## Order matters { #order-matters }

When creating *path operations*, you can find situations where you have a fixed path.

Like `/users/me`, let's say that it's to get data about the current user.

If you declare the return type, FastAPI will use it to **validate** the data, **document** it in OpenAPI, **filter** it, and **serialize** it using Pydantic.

/// tip

As Pydantic will serialize it in the **Rust** side, you will get much higher **performance** than if you don't declare a return type.

///

### Non-async *path operation functions* { #non-async-path-operation-functions }

///

...so, you are a [team member of FastAPI](./fastapi-people.md#team)? Wow, you are so cool! 😎

You can help with everything on [Help FastAPI - Get Help](./help-fastapi.md) the same ways as external contributors. But additionally, there are some tasks that only you (as part of the team) can perform.

 *
 * <h3>How to get an instance</h3>
 *
 * <p>We encourage you to return {@code ListenableFuture} from your methods so that your users can
 * take advantage of the {@linkplain Futures utilities built atop the class}. The way that you will
 * create {@code ListenableFuture} instances depends on how you currently create {@code Future}
 * instances:
 *
 * <ul>

In most cases you would (and should) have a "termination proxy" handling HTTPS for you on top, this will depend on how you deploy your application, your provider might do this for you, or you might need to set it up yourself.

/// tip

To protect your rights, we need to make restrictions that forbid anyone
to deny you these rights or to ask you to surrender the rights. These
restrictions translate to certain responsibilities for you if you
distribute copies of the software, or if you modify it.

For example, if you distribute copies of such a program, whether gratis
or for a fee, you must give the recipients all the rights that you have.

/*
 * Copyright (C) 2012 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

        By asking questions in a structured way (following this) it will be much easier to help you.

        And there's a high chance that you will find the solution along the way and you won't even have to submit it and wait for an answer. 😎

In some cases, you may want to override the logic used by the `Request` and `APIRoute` classes.

In particular, this may be a good alternative to logic in a middleware.

For example, if you want to read or manipulate the request body before it is processed by your application.

/// danger

This is an "advanced" feature.

If you are just starting with **FastAPI** you might want to skip this section.

///

from fastapi import FastAPI

description = """
ChimichangApp API helps you do awesome stuff. 🚀

## Items

You can **read items**.

## Users

You will be able to:

* **Create users** (_not implemented_).
* **Read users** (_not implemented_).
"""

app = FastAPI(
    title="ChimichangApp",
    description=description,
    summary="Deadpool's favorite app. Nuff said.",
    version="0.0.1",