I develop some premium apps that users can download directly from my landing pages, so the installs aren't going through play store.
The apps communicate with my server for tracking purposes, and I would like to be able to pinpoint which app installs correspond with which download entries in my downloads tracking system, to be able to accurately analyze my campaigns.
Is there a way in which I can identify the user or device in relation to the APK download?
Edit:
What I've tried so far is to create a fingerprint using data such as IP, country, browser user agent and android version, save it in the database, and have the app send me the same data after it's first opened, then try to find an entry like that, but it fails more often than not (can't find a corresponding entry).
I can't post that part of code, due to company policy (Yeah, I know...) -_-
As some extra info, my pages are using php in the backend. I've been trying to create some kind of fingerprint of the user device and compare it after the app is installed and opened with the fingerprint database on my server, but it's not a good system...