Android
Android is a smartphone operating system (OS) developed by Google. Android phones typically come with several built-in applications and also support third-party programs. Android-based phones may have different graphical user interfaces GUIs even though they use the same OS. Developers can create programs for Android using the free Android SDK (Software Developer Kit). Android programs are written in Java.
Web Based Apps:
Web apps are sometimes designed to look and behave like apps when the purpose is simply to make content or functionality available on mobile.