Apple recently cracked down on Cal AI, an app owned by MyFitnessPal that tried to skirt Apple's in-app purchase rules. Apple told TechCrunch that it briefly pulled the calorie-counting app last week for violating purchasing guidelines and using a deceptive billing design.

When the app was pulled last week, there was speculation that it was removed for implementing web-based payments, something that is now allowed in the U.S. Apple said that's not the whole story, though, and the app was violating other guidelines.

Apple's ongoing legal battle with Epic Games led a judge to force Apple to allow U.S. developers to include links to external payment systems in their apps, but apps that are not classified as reader apps also have to include an in-app purchase option. Apps like Netflix and Spotify that offer streaming content are considered reader apps, but Cal AI is not.

As a non-reader app, Cal AI was allowed to direct users to a non-Apple purchase option for a subscription, which it did with a purchase flow using Stripe, but the purchase option should have been displayed alongside an in-app purchase option. Apple said Cal AI bypassed its required in-app purchase flow, misled customers by displaying the weekly calculated pricing more prominently than the amount the user would be billed, and had a free trial toggle that did not make the subscription's automatic renewal clear.

The app also prompted users who declined the initial subscription to agree to a second, different subscription purchase flow, leading to multiple negative reviews for its confusing third-party payment options.

Cal AI fixed the issues that Apple brought up, and the app returned to the App Store. TechCrunch suggests that Cal AI was experimenting to see whether Apple was still enforcing its rules following the court ruling requiring it to allow external payments in apps. With the Cal AI crackdown, Apple made it clear that it is indeed policing external payments.

MyFitnessPal and Cal AI have not commented on the situation. After returning to the ‌App Store‌, Cal AI is once again the number four app on the ‌App Store‌'s Health and Fitness charts.