// You could create an env var MY_NAME with
    $ export MY_NAME="Wade Wilson"

    // Then you could use it with other programs, like
    $ echo "Hello $MY_NAME"

    Hello Wade Wilson
    ```

    </div>

=== "🚪 📋"

    <div class="termy">

    ```console
    // Create an env var MY_NAME
    $ $Env:MY_NAME = "Wade Wilson"

    // Use it with other programs, like

    // You could create an env var MY_NAME with
    $ export MY_NAME="Wade Wilson"

    // Then you could use it with other programs, like
    $ echo "Hello $MY_NAME"

    Hello Wade Wilson
    ```

    </div>

=== "Windows PowerShell"

    <div class="termy">

    ```console
    // Create an env var MY_NAME
    $ $Env:MY_NAME = "Wade Wilson"

    // Use it with other programs, like

    $ export MY_NAME="Wade Wilson"

    // 然后您可以与其他程序一起使用它，例如
    $ echo "Hello $MY_NAME"

    Hello Wade Wilson
    ```

    </div>

=== "Windows PowerShell"

    <div class="termy">

    ```console
    // 创建一个名为 MY_NAME 的环境变量
    $ $Env:MY_NAME = "Wade Wilson"

    // 与其他程序一起使用它，例如
    $ echo "Hello $Env:MY_NAME"

    Hello Wade Wilson
    ```

    </div>

    $ export MY_NAME="Wade Wilson"

    // Dann könnten Sie diese mit anderen Programmen verwenden, etwa
    $ echo "Hello $MY_NAME"

    Hello Wade Wilson
    ```

    </div>

=== "Windows PowerShell"

    <div class="termy">

    ```console
    // Erstelle eine Umgebungsvariable MY_NAME
    $ $Env:MY_NAME = "Wade Wilson"

    // Verwende sie mit anderen Programmen, etwa

And we can add a list of `dependencies` that will be added to all the *path operations* in the router and will be executed/solved for each request made to them.

!!! tip

* 📝 Fix broken link in `docs/en/docs/tutorial/sql-databases.md`. PR [#10765](https://github.com/tiangolo/fastapi/pull/10765) by [@HurSungYun](https://github.com/HurSungYun).
* 📝 Add External Link: FastAPI application monitoring made easy. PR [#10917](https://github.com/tiangolo/fastapi/pull/10917) by [@tiangolo](https://github.com/tiangolo).

    img: https://fastapi.tiangolo.com/img/sponsors/codacy.png
bronze:
  - url: https://www.exoflare.com/open-source/?utm_source=FastAPI&utm_campaign=open_source
    title: Biosecurity risk assessments made easy.
    img: https://fastapi.tiangolo.com/img/sponsors/exoflare.png
  - url: https://testdriven.io/courses/tdd-fastapi/
    title: Learn to build high-quality web apps with best practices

If you use a `try` block in a dependency with `yield`, you'll receive any exception that was thrown when using the dependency.

For example, if some code at some point in the middle, in another dependency or in a *path operation*, made a database transaction "rollback" or create any other error, you will receive the exception in your dependency.

So, you can look for that specific exception inside the dependency with `except SomeException`.

It was one of the first extremely fast Python frameworks based on `asyncio`. It was made to be very similar to Flask.

!!! note "Technical Details"
    It used <a href="https://github.com/MagicStack/uvloop" class="external-link" target="_blank">`uvloop`</a> instead of the default Python `asyncio` loop. That's what made it so fast.

## Adding ASGI middlewares

As **FastAPI** is based on Starlette and implements the <abbr title="Asynchronous Server Gateway Interface">ASGI</abbr> specification, you can use any ASGI middleware.

A middleware doesn't have to be made for FastAPI or Starlette to work, as long as it follows the ASGI spec.

In general, ASGI middlewares are classes that expect to receive an ASGI app as the first argument.