title: Share an In-App Purchase between iOS and OS X?
body: <p>I noticed Bear Notes has a subscription in-app purchase that if you buy it on iOS it also unlocks it on Mac OS X, and vice-versa.</p>
  
  <p>I've seen a few clues out there as to how to do it, such as using the App Store receipt, but I don't know how Bear was able to identify that I'm the same user on my Mac as I am on iOS.</p>
  
  <p>If it was using a receipt, then it would have to take the receipt from iOS, send it to the server, but then know do you fetch the receipt for me when I'm on my Mac?</p>
  
  <p>As far as I remember, I didn't have to identify myself in either app.</p>