And then, you could give that JWT token to a user (or bot), and they could use it to perform those actions (drive the car, or edit the blog post) without even needing to have an account, just with the JWT token your API generated for that.

Using these ideas, JWT can be used for way more sophisticated scenarios.

### Run Automatically on Startup

In general, you will probably want the server program (e.g. Uvicorn) to be started automatically on server startup, and without needing any **human intervention**, to have a process always running with your API (e.g. Uvicorn running your FastAPI app).

### Separate Program

### Docs

* 📝 Tweak wording in `help-fastapi.md`. PR [#11040](https://github.com/tiangolo/fastapi/pull/11040) by [@tiangolo](https://github.com/tiangolo).

* `$`: ends there, doesn't have any more characters after `fixedquery`.

If you feel lost with all these **"regular expression"** ideas, don't worry. They are a hard topic for many people. You can still do a lot of stuff without needing regular expressions yet.

But whenever you need them and go and learn them, know that you can already use them directly in **FastAPI**.

### Pydantic v1 `regex` instead of `pattern`

                oauth2.callback({auth: oauth2.auth, token: qp, isValid: isValid, redirectUrl: redirectUrl});
            }
            window.close();
        }

        if (document.readyState !== 'loading') {
            run();
        } else {
            document.addEventListener('DOMContentLoaded', function () {
                run();
            });
        }
    </script>
    </body>
    </html>

    title: Inbetriebnahme eines scikit-learn-Modells mit ONNX und FastAPI
  - author: Felix Schürmeyer
    author_link: https://hellocoding.de/autor/felix-schuermeyer/
    link: https://hellocoding.de/blog/coding-language/python/fastapi
    title: REST-API Programmieren mittels Python und dem FastAPI Modul
  Japanese:
  - author: '@bee2'
    author_link: https://qiita.com/bee2

This can be very useful for setting up **resources** that you need to use for the whole app, and that are **shared** among requests, and/or that you need to **clean up** afterwards. For example, a database connection pool, or loading a shared machine learning model.

## Use Case

Let's start with an example **use case** and then see how to solve it with this.

Nevertheless, as this would mean waiting for the response to travel through the network while unnecessarily holding a resource in a dependency with yield (for example a database connection), this was changed in FastAPI 0.106.0.

!!! tip

You can create and use environment variables in the shell, without needing Python:

=== "Linux, macOS, Windows Bash"

    <div class="termy">

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

You will be able to return a database model and it will read the data from it.

#### Technical Details about ORM mode

SQLAlchemy and many others are by default "lazy loading".

That means, for example, that they don't fetch the data for relationships from the database unless you try to access the attribute that would contain that data.

For example, accessing the attribute `items`: