Researchers spot privacy concerns in APIs that share battery levels with site owners.
Researchers spot privacy concerns in APIs that share battery levels with site owners.

A battery status API, intended to allow site owners to serve low-power versions of sites and web apps, is being used to track user behavior.

Introduced in HTML 5, the API allows site owners to see a device's battery percentage and the time it would take to charge said device to prevent the execution of intensive operations if a user's battery was low, security and privacy technology researcher Lukasz Olejnik said in an Aug. 1 blog post.

Olejnik said the tracker could be used to collect behavior analytics, identify users in otherwise identical computer installations, record how often a user's device is under heavy use, and in some cases identify a user's battery capacity.

The information potentially could be monetized as people may be prone to pay more for a service if their battery levels are low, the blog said.