Microsoft acquired Xamarin in 2016 as part of its push to help developers build mobile apps with .NET and C#.
Xamarin was founded by engineers associated with the Mono project, including Nat Friedman and Miguel de Icaza. Its tools allowed developers to use C# and share code while creating applications for Android, iOS, and Windows. That made it especially attractive to developers already working in Microsoft's Visual Studio ecosystem.
Microsoft announced a definitive agreement to acquire Xamarin on February 24, 2016. At Microsoft's Build conference later that year, the company announced that Xamarin tools would be integrated into Visual Studio and made available across its editions. Xamarin's technology later became part of Microsoft's broader .NET strategy, including the transition toward .NET MAUI.
Xamarin is sometimes confused with Unity, which is primarily a game engine, or PhoneGap, which uses web technologies for cross-platform apps. Xamarin's distinctive foundation was native mobile development through C# and the .NET platform.