I am developing an app, and we are at the payment integration stage.
The app uses a large array of cloud services and requires a subscription service to be economically viable. The current market plan is to make 20 uses of the app's features for free, and then usage above that requires a paid account.
The app store terms of use make it very clear that I cannot simply have users sign up for a paid account on a website and use that to unlock more uses of the service (if this is incorrect, please tell me) and that unlocking services in the app store would require using Apple Pay and IAP.
My problem, however, is that one user account is intended to be used across multiple platforms (iOS, website, Play Store, etc.), much like a Netflix account can be used on any device regardless of sign-up method.
My questions:
Am I allowed to have users who have signed up and subscribed on the website / another mobile platform use the service on iOS? For example, they sign up on the site and then use the app by simply signing in to their paid, premium account and the features unlock?
Also, Spotify appears to only unlock premium uses of the service through their website, which unlocks features in the app: https://support.spotify.com/is/article/spotify-through-the-app-store/
How is this possible? Obviously I would prefer not to forward the Apple charges onto my users and make things more expensive for iOS purchases. Can I simply have all uses above 20 return a "Please go to the site and become a premium member to continue using the service" message?
