Please review the Apple Developer documentation at
rich kubota - firstname.lastname@example.org
developer technical support CoreOS/Hardware/MFI
> I can certainly store each receipt type from iOS and Mac into my DB separately and do the validations directly with AppStore and MacStore respectively. But I can't stop the user from purchasing the
standardsubscription twice, once from iOS and then again from Mac.
"But I can't stop" Yes you can. Before the user in iOS or Mac can purchase the subscription you require that they log onto your DB. If your DB indicates they have a subscription on their other system (i.e. Mac or iOS), don't let them make the purchase.