An app developer has discovered a number of scam applications available to consumers in the Apple App Store, some of which have made millions of dollars from unsuspecting iPhone users.

9to5Mac reports that iOS developer Kosta Eleftheriou has been highlighting a growing issue in recent weeks — scam apps available in the Apple app store. Each of the scam apps Eleftheriou found appeared to use the same method including boosting their apparent legitimacy in the app store by purchasing fake reviews.

Eleftheriou is the developer of FlickType, a popular Apple Watch keyboard application. Eleftheriou is also of the developers of the Flesky keyboard app which was acquired by Pinterest, and Blind Type which was acquired by Google.

A week ago, Eleftheriou began highlighting applications that were basically non-functional copies of FlickType. One app in particular, KeyWatch, was a carbon copy of Eleftheriou’s app, according to the developer. In a Twitter post, Eleftheriou stated:

Just a few months ago, I was way ahead of my competition. By the time they figured out just how hard autocorrect algorithms were, I was already rolling out the swipe version of my keyboard, quickly approaching iPhone typing speeds. So how did they beat me?

First, they made an app that appeared to fulfill the promise of a watch keyboard – but was practically unusable. Then, they started heavily advertising on FB & Instagram, using my own promo video, of my own app, with my actual name on it.

When users downloaded the app, they were met with a blank interface with a large “Unlock now” button. Upon tapping the button they were prompted to accept an Apple subscription of $8 per week. Even after paying the subscription fee, the app failed to work.

However, despite the app’s lack of function, it had quite a high app store rating after the app’s developers allegedly purchased fake ratings and reviews. According to data from Appfigures, the scam app KeyWatch generated $2 million a year through the App Store scam.

After Eleftheriou’s Twitter thread gained popularity, Apple investigated and removed KeyWatch and a number of similar scam Apple Watch keyboard apps from the App Store. However, Eletheriou noted that while the app itself was removed, Apple did not disable the developer’s account.

Since then, Eleftheriou has exposed a number of additional scam apps on the App Store. He even compiled a thread titled “How to spot a $5M/year scam on the App Store, in 5 minutes flat.” In this thread, he pointed out an app called Star Gazer+ which is still available on the App Store with a 4.4 rating from over 80,000 allegedly fake users.

Read more at 9to5Mac here.

Lucas Nolan is a reporter for Breitbart News covering issues of free speech and online censorship. Follow him on Twitter @LucasNolan or contact via secure email at the address lucasnolan@protonmail.com