https://www.cnet.com/news/apple-to-face-eu-antitrust-investigation-thanks-to-spotify-says-report/

In the complaint, Spotify said Apple charged subscription companies a 30% fee for in-app purchases while other non-subscription apps didn't have to pay any fee. The music-streaming company stated in its complaint that Apple is attempting to stifle competitive music services.

The iPhone maker responded in March saying the allegations were misleading and that "Spotify wouldn't be the business they are today without the App Store ecosystem." Apple also said the 30% fee drops to 15% after the first year and continues to drop the following years. Apple accused Spotify of wanting a "free ride."