> For the complete documentation index, see [llms.txt](https://docs.arkannis.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.arkannis.net/programming/postman/environment-variables.md).
# Environment Variables
* Environment variables allow developers to switch between DEV and PROD for example
* It allows for definition of different variables based on needs
* Allows to define variables dynamically
#### To define Environment variables such as the URL:
* After this has been defined, you can call it in the operation path:
#### It also became harder to test our API since we have added the login logic and protected routes
* So to save some time, we can automate the definition of the JWT as an environment variable through code
* This should be done under the `login` path operation as to define it directly as you log in
* Navigate to the `Tests` tab and select `Set an environment variable`
* Use the following code to set it dynamically
```python
pm.environment.set("JWT", pm.response.json().access_token);
```
* The above code sets the environment variable as `JWT` with the value fetching first the response, then transforming it into a JSON output from which the variable named in the return output is called
* In our case `access_token` but can be anything as it's app defined under the route return
* After this is defined, we can call it under the authorization tab as `{{JWT}}` to always have it update on login