Judge Yvonne Gonzalez Rodgers ordered Apple to immediately drop the 27% fee for developers linking users to the web for purchases.
Changes have already been reflected in Apple's App Review Guidelines following the court decision.
The new rules affect only the U.S. App Store, further fragmenting App Store regulations along geopolitical boundaries.
Major companies like Patreon, Spotify, and Epic Games are making adjustments to their app practices in response to the ruling, signaling potential changes in business models for indie developers.