I'll tell you a bit more about these **concepts** here, and that would hopefully give you the **intuition** you would need to decide how to deploy your API in very different environments, possibly even in **future** ones that don't exist yet.

By considering these concepts, you will be able to **evaluate and design** the best way to deploy **your own APIs**.

But **FastAPI** will handle it, give you the correct data in your function, and validate and document the correct schema in the *path operation*.

You can also declare singular values to be received as part of the body.

**FastAPI** is all based on these type hints, they give it many advantages and benefits.

But even if you never use **FastAPI**, you would benefit from learning a bit about them.

!!! note
    If you are a Python expert, and you already know everything about type hints, skip to the next chapter.

## Motivation

# Conditional OpenAPI

If you needed to, you could use settings and environment variables to configure OpenAPI conditionally depending on the environment, and even disable it entirely.

## About security, APIs, and docs

Hiding your documentation user interfaces in production *shouldn't* be the way to protect your API.

That doesn't add any extra security to your API, the *path operations* will still be available where they are.

    Using a relative URL is important to make sure your application keeps working even in an advanced use case like [Behind a Proxy](../../advanced/behind-a-proxy.md){.internal-link target=_blank}.

So, install PassLib with Bcrypt:

<div class="termy">

```console
$ pip install "passlib[bcrypt]"

---> 100%
```

</div>

!!! tip
    With `passlib`, you could even configure it to be able to read passwords created by **Django**, a **Flask** security plug-in or many others.

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

### Order of tags

The order of each tag metadata dictionary also defines the order shown in the docs UI.

For example, even though `users` would go after `items` in alphabetical order, it is shown before them, because we added their metadata as the first dictionary in the list.

## OpenAPI URL

"docs_src/dependencies/tutorial008b_an_py39.py" = ["B904"]


[tool.ruff.lint.isort]
known-third-party = ["fastapi", "pydantic", "starlette"]

[tool.ruff.lint.pyupgrade]
# Preserve types, even if a file imports `from __future__ import annotations`.

!!! tip
    Having `dependencies` in the `APIRouter` can be used, for example, to require authentication for a whole group of *path operations*. Even if the dependencies are not added individually to each one of them.

!!! check

* **After** obtaining a secure connection, the communication protocol is **still HTTP**.
    * The contents are **encrypted**, even though they are being sent with the **HTTP protocol**.