Curious hobby developer here. After getting curious about historical data on CE prices I decided to poke around, only to find that there isn't any. No sites I could find tracked it, and the closest I came was seeing an android app that allowed you to see [i]current[/i] prices, but as far as I can tell the developer didn't collect them. So, my question is thus: Is there some sort of API (even via Steam API), or even just a login/logout that would give me this data? I know I'm not alone in wondering this but it seems all prior questions have gone unanswered.

If there is no such API, though, then how was the android app able to function? Did the developer simply maintain a database of some sort?