Regulators in different countries are scrutinizing how Apple extracts payments through the App Store.
The issue will be the focal point of a federal court trial scheduled to start May 3.
Epic Games, the maker of the popular video game Fortnite, will try to prove its contention that Apple has turned its app store into a weapon for shaking down smaller companies to boost its own already huge profits.
Apple insists its fees are reasonable in light of its massive investment in the iPhone and that its “walled garden” approach helps protect the security of its customers and their devices.
Apple dropped Fortnite from their app stores after Epic Games introduced a direct payment plan that bypasses their platforms.
Apple takes a 30% cut from in-app revenue purchases in games, which has long been a sore spot with developers.
Fortnite is free, but users can pay for in-game additions like special weapons and new characters.
Apple CEO Tim Cook is expected to testify during the trial, which begins Monday at the US District Court in San Francisco.