What is Xamarin?
Xamarin’s Mono-based products enable .NET developers to use their existing code, libraries and tools (including Visual Studio*), as well as skills in .NET and the C# programming language, to create mobile applications for the industry’s most widely-used mobile devices, including Android-based smartphones and tablets, iPhone, iPad and iPod Touch.
Xamarin is a tool in the Cross-Platform Mobile Development category of a tech stack.
Why developers like Xamarin
Power of c# on mobile devices
Native apps with native ui controls
Sharing more than 90% of code over all platforms
Ability to leverage visual studio
Many great c# libraries