> For the complete documentation index, see [llms.txt](https://developer.harness.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.harness.io/feature-flags/use-feature-flags/use-ff/ff-data/anonymous-users-maus.md).

# Track Anonymous Users & Monthly Active Users

This topic defines anonymous users, how their data is handled in Harness Feature Flags, and how they relate to the Monthly Active Users (MAUs) count.

{% hint style="info" %}
**NOTE**

Monthly Active Users (MAUs) are only applicable to client-side applications (JavaScript, iOS, Android, React, etc.).
{% endhint %}

### How do anonymous users contribute to MAUs? <a href="#how-do-anonymous-users-contribute-to-maus" id="how-do-anonymous-users-contribute-to-maus"></a>

MAUs are defined as unique end users evaluating flags from client-side SDKs (JavaScript, iOS, Android, React, etc.) over a 30-day period. If a user evaluates flags across multiple devices and sessions in a 30-day period, we count this as 1 MAU.

* Anonymous users can be assigned a target ID as any other target would, ensuring that multiple visits only account for one MAU. Essentially, you'd create a single target that applies to all of your anonymous traffic, and the anonymous traffic would be counted as one MAU.