> For the complete documentation index, see [llms.txt](https://docs.helmut.de/helmut4-releases/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.helmut.de/helmut4-releases/helmut4-components/streamdesigner/wildcards/user-related-wildcards-10/user-os.md).

# User OS

This wildcard will be substituted with the client's operating system (referring to the client connected to the browser).

The valid values for this wildcard include:

* mac
* win
* linux

{% hint style="info" %}
This wildcard tells you the operating system of your client, accessing the Helmut4 website, the operating system of your job/stream might be another - consider to have a look into this wildcard [local OS](/helmut4-releases/helmut4-components/streamdesigner/wildcards/local-environment-related-wildcards-6/local-os.md)
{% endhint %}

{% hint style="warning" %}
Please note that Helmut4 employs case sensitivity for all types of variables.
{% endhint %}