Android is a mobile operating system developed by Google which has 87% of market share in the world.
Xamarin is a Microsoft-owned San Francisco, founded in May 2011 by the engineers that created Mono, Mono for Android and MonoTouch, which are cross-platform implementations .With Certfication.
Ionic is the app platform for web developers. Build amazing mobile, web, and desktop apps all with one shared code base and open web standards.
Flutter is an open-source mobile application development SDK created by Google. It is used to develop applications for Android and iOS, as well as being the primary method of creating applications for Google Fuchsia.
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