We are trying to find a way to identify specific purchases when using Google in-app billing via Google Play—specifically, to identify a specific purchased product on a new device, or after a memory wipe. I've considered trying to retrieve the Google ID used in purchase, as in this question, but it's proven problematic.
However, the developer payload might provide a solution, but this depends on how it behaves. Basically what I am hoping is that, when a purchase is restored using RESTORE_TRANSACTIONS, the developer payload put into the original purchase request is returned. If so we can use this payload to identify a user: when they install the application on a new device, we restore transactions, and get the developer payload to identify them; otherwise we assume they are a new user and generate a new developer payload.
Can this work? Does the developer payload persist for managed products?
