Thunkable X
Thuckable X is a developing platform that allows you to create compelling and engaging apps for free, and all you need to sign in with google.
4 Alternatives To Thunkable X
Android
Android is an open source mobile operating system initially released by Google in 2008 and has since become of the most widely used operating systems on any platform.
Qt
C++
Thunkable
Powerful but easy to use, drag-and-drop mobile app builder.
Xamarin
Create iOS, Android and Mac apps in C#