I am completely sure that Apple gets 30% of the in app purchase in Spotify’s iOS app. But now with the new WWDC in app purchase update, after a year it will only be a 85/15 split so it’ll be a bit better for Spotify.

But that’s the whole reason that Spotify is getting mad. It is trying to get around this revenue split by having customers sign in through their website. Apple is rejecting their app because of “business model” reasons and they are forcing Spotify to use their subscription payment system. So even if Spotify makes their iOS app a web app (which in my opinion would diminish the UX) it wouldn’t matter because Apple would still reject it.