Restore in-app purchases when same native (Apple/Google) account on device but different app accounts

Question

You have a mobile app (Android/iOS) that requires the user to sign-in. The mobile app offers in-app purchases. A user makes an in-app purchase while * signed in as X on the

Answer 1

If you have your own account based system, you aren't required to restore purchases from the device receipt if they can be restored by logging in to their (your) account. Apple vaguely mentions this in their docs as do service providers.

From Apple (their example is iOS/macOS but might as well be iOS/Android):

You could let users who have a subscription in an iOS app access the content from a macOS app (or vice versa), but implementing that functionality is your responsibility. You would need a system to identify users and keep track of the content they are subscribed to, similar to what you would implement for an app that uses non-renewable subscriptions.

From RevenueCat:

Using an externally managed App User ID also provides a mechanism by which to restore purchases in a few scenarios:

...

2. When the user logs in on multiple devices - you can honor a subscription that was purchased on one device across any other platform.

You'll notice large, cross-platform, subscription apps like Netflix don't have a restore purchases button anywhere. As you've pointed out, restoring purchases could allow a single purchase receipt to be shared across multiple users that log-in on the same device.

Disclaimer: I work at RevenueCat