User Guide: SDKs > VoltMX Iris SDK > Setting User ID
Setting User ID
The setUserID API sets the user ID for the data gathered from an application. The user ID allows the data to be tracked on a user basis for broad analysis like how many different users used the application. It also helps to track activities of a specific user, which can help in seeing what activities were done before a crash, or what events led to a transaction not passing through. The user ID allows the same user to be tracked across different devices as well.
Note: HCLMetricsService.setUserId has been removed from apps built with Volt MX Iris Enterprise.