Following news this week that a number of iPhone apps have been using analytics services to record data relating to how people interact with their phone, Apple Inc. Thursday warned developers that if they don’t disclose the existence of such software, their apps could be removed from the App Store.

The stern warning came after an investigation by TechCrunch Thursday revealed that popular apps were secretly recording how users swiped and tapped while using the app. The companies using the software included retail outlets, airlines, banks, travel sites and hoteliers.

The investigation found that the analytics software embedded into the apps would allow developers to see what are called “session replays.” These replays would essentially let developers see how a user interacted with an app and then relay that information back to a company.

The company behind the technology is called Glassbox. In a statement to The Verge, Glassbox said, “This information helps companies better understand how consumers are using their services, and where and why they are struggling.” The company said it was not “spying” on users, but helping improve the user experience, adding that consumers should be informed by companies that their data is being recorded.

It was also revealed that in some cases users’ passport numbers and credit card data were contained in the session replay.

Some big names such as Expedia, Hotels.com, and Singapore Airlines had this software embedded into their apps and, according to the investigation, none of them disclosed that to users. Soon after the investigation, said these developers are “in violation of these strict privacy terms and guidelines.”

“Protecting user privacy is paramount in the Apple ecosystem,” a spokesperson for Apple said. “Our App Store Review Guidelines require that apps request explicit user consent and provide a clear visual indication when recording, logging or otherwise making a record of user activity.”

According to TechCrunch, developers have already been contacted by Apple and told to remove the recording software, disclose that it’s there or risk facing immediate action.

“Your app uses analytics software to collect and send user or device data to a third party without the user’s consent,” Apple wrote in an email to one developer, as reported by TechCrunch. “Apps must request explicit user consent and provide a clear visual indication when recording, logging, or otherwise making a record of user activity.”

Image: Blake Patterson/Flickr