## Running on Startup

In most cases, when you create a web API, you want it to be **always running**, uninterrupted, so that your clients can always access it. This is of course, unless you have a specific reason why you want it to run only in certain situations, but most of the time you want it constantly running and **available**.

### In a Remote Server

Most of these settings are variable (can change), like database URLs. And many could be sensitive, like secrets.

For this reason it's common to provide them in environment variables that are read by the application.

## Environment Variables

!!! tip

    client to send the form field `grant_type` with the value `"password"`, which
    is required in the OAuth2 specification (it seems that for no particular reason),
    while for `OAuth2PasswordRequestForm` `grant_type` is optional.

    Read more about it in the

    author_link: https://www.linkedin.com/in/navule/
    link: https://www.tutlinks.com/deploy-fastapi-on-ubuntu-gunicorn-caddy-2/
    title: Deploy FastAPI on Ubuntu and Serve using Caddy 2 Web Server
  - author: Patrick Ladon
    author_link: https://dev.to/factorlive
    link: https://dev.to/factorlive/python-facebook-messenger-webhook-with-fastapi-on-glitch-4n90
    title: Python Facebook messenger webhook with FastAPI on Glitch

Aso, when returning several objects, like in `get_users`, we directly call `list`, like in:

```Python
list(models.User.select())
```