When I first read the docs on iOS App Store in-app subscriptions, I was surprised at how complicated it was. I was even more surprised when the docs had gaps in critical areas, such as how to determine when a subscription was renewed, after I went down the wrong path on that. Then there was some inconsistency between documented and actual JSON responses when dealing with receipt verification and status update notifications. I scrounged on the developer forums and Stack Overflow just to make non-intuitive guesses as to what Apple intended for developers to do.
Anyway, I couldn't find any out-of-box open source solutions. It would've been convenient to refer to an up-to-date implementation when I needed to. So I wrote my own subscription server and put it on GitHub.
https://github.com/carpenterscode/superscribe
I'd love some help for the new server-to-server notifications coming down the pipeline for this Fall or whenever they actually come, but first…
1) How did you implement App Store subscriptions? (existing solutions, in-house, etc.)
2) What feedback do you have for the subscription server I posted above? (whether technical design, code, or what to do next)