* `expose_headers` - Indicate any response headers that should be made accessible to the browser. Defaults to `[]`.
* `max_age` - Sets a maximum time in seconds for browsers to cache CORS responses. Defaults to `600`.

The middleware responds to two particular types of HTTP request...

### CORS preflight requests { #cors-preflight-requests }

## Container Images { #container-images }

Docker has been one of the main tools to create and manage **container images** and **containers**.

```txt
fastapi[standard]>=0.112.0,<0.113.0
```

that would mean that you would use the versions `0.112.0` or above, but less than `0.113.0`, for example, a version `0.112.2` would still be accepted.

If you use any other tool to manage your installations, like `uv`, Poetry, Pipenv, or others, they all have a way that you can use to define specific versions for your packages.

## Available versions { #available-versions }

Once you are ready and want to use a tool to **manage the entire project**, packages dependencies, virtual environments, etc. I would suggest you try <a href="https://github.com/astral-sh/uv" class="external-link" target="_blank">uv</a>.

`uv` can do a lot of things, it can:

* **Install Python** for you, including different versions
* Manage the **virtual environment** for your projects
* Install **packages**

# FastAPI CLI { #fastapi-cli }

**FastAPI CLI** is a command line program that you can use to serve your FastAPI app, manage your FastAPI project, and more.

When you install FastAPI (e.g. with `pip install "fastapi[standard]"`), it includes a package called `fastapi-cli`, this package provides the `fastapi` command in the terminal.

To run your FastAPI app for development, you can use the `fastapi dev` command:

<div class="termy">

```console

- name: agentkit
  html_url: https://github.com/BCG-X-Official/agentkit
  stars: 1779
  owner_login: BCG-X-Official
  owner_html_url: https://github.com/BCG-X-Official
- name: manage-fastapi
  html_url: https://github.com/ycd/manage-fastapi
  stars: 1770
  owner_login: ycd
  owner_html_url: https://github.com/ycd
- name: ormar
  html_url: https://github.com/collerek/ormar
  stars: 1766
  owner_login: collerek

But once you know the basic information of **HTTPS for developers** you can easily combine and configure different tools to help you manage everything in a simple way.

* Fix 2 typos in docs. PR [#1324](https://github.com/tiangolo/fastapi/pull/1324) by [@waynerv](https://github.com/waynerv).
* Update CORS docs, fix correct default of `max_age=600`. PR [#1301](https://github.com/tiangolo/fastapi/pull/1301) by [@derekbekoe](https://github.com/derekbekoe).

Every time you "log in with" Facebook, Google, GitHub, Microsoft, X (Twitter), that application is using OAuth2 with scopes.

In this section you will see how to manage authentication and authorization with the same OAuth2 with scopes in your **FastAPI** application.

/// warning

This is a more or less advanced section. If you are just starting, you can skip it.