App that shows what's passing in sky? I'm not an astronomer but I enjoy looking up at the sky.

So tonight I saw something moving in the sky. It looked like a star, and it was definitely not a plane (I checked in flightradar).

Is there an app, similar to flightradar for planes, that will tell me what's traveling above me in the sky?
Chris Peat maintains a very sophisticated database of satellites and their visibilites at http://heavens-above.com, and there is an app available.