Amazon.com was sued on Wednesday by consumers who accused the retailing giant of secretly tracking their movements through their cellphones, and selling data it collects.

According to a proposed class action in San Francisco federal court, Amazon obtained “backdoor access” to consumers’ phones by providing tens of thousands of app developers with code known as Amazon Ads SDK to be embedded in their apps.

This allegedly enabled Amazon to collect an enormous amount of timestamped geolocation data about where consumers live, work, shop and visit, revealing sensitive information such as religious affiliations, sexual orientations and health concerns.
“Amazon has effectively fingerprinted consumers and has correlated a vast amount of personal information about them entirely without consumers’ knowledge and consent,” the complaint said.

The complaint was filed by Felix Kolotinsky of San Mateo, California, who said Amazon collected his personal information through the “Speedtest by Ookla” app on his phone.

He said Amazon’s conduct violated California’s penal law and a state law against unauthorized computer access, and seeks unspecified damages for millions of Californians.

Amazon, based in Seattle, did not immediately respond to requests for comment. Lawyers for the plaintiff did not immediately respond to requests for additional comment.

Individuals and regulators are increasingly complaining that companies are trying to profit from information gathered without consent from cellphones.

On Jan. 13, the state of Texas sued Allstate for allegedly tracking drivers through cellphones, using the data to raise premiums or deny coverage, and selling the data to other insurers.

Allstate said its data collection fully complies with all laws and regulations. At least eight similar private lawsuits against Allstate have been subsequently filed.

The case is Kolotinsky v Amazon.com Inc et al, U.S. District Court, Northern District of California, No. 25-00931.