In a team of 4 people (1 iOS, 1 Android, 1 backend, 1 designer) we created the Qube application. We've worked on this in our free time and are still busy implementing new features.
The purpose of Qube is to combine all the easy-to-use tools in one application so you can easier meet up with your friends.
Technologies, libraries and tools
Android X, based on icapps Android architecture components
Firebase crashlytics, analytics and authentication via text message