Xamarin is a Microsoft-owned San Francisco-based software company founded in May 2011[2] by the engineers that created Mono,[3] Xamarin.Android (formerly Mono for Android) and Xamarin.iOS (formerly MonoTouch), which are cross-platform implementations of the Common Language Infrastructure (CLI) and Common Language Specifications (often called Microsoft .NET).

After Microsoft first announced their .NET Framework in June 2000,[8] de Icaza began investigating whether a Linux version was feasible.

[12][13] On May 16, 2011, Miguel de Icaza announced on his blog that Mono would be developed and supported by Xamarin, a newly formed company that planned to release a new suite of mobile products.

[14] After Xamarin was announced, the future of the project was questioned since MonoTouch and Mono for Android would now be in direct competition with the existing commercial offerings owned by Attachmate.

[23] Several investors from their Series A funding also participated, including Charles River Ventures, Floodgate, and Ignition Partners.

[31] Xamarin extends the .NET developer platform with tools and libraries specifically for building apps for Android, iOS, tvOS, watchOS, macOS, and Windows (UWP) primarily with C# in Visual Studio.

[21] Xamarin also released a component store to integrate backend systems, 3rd party libraries, cloud services and UI controls directly into mobile apps.

Mobile Blazor Bindings allow developers to build native Android and iOS using C#, .NET, and web programming patterns.

[44] Xamarin is a .NET developer platform made up of tools, programming languages, and libraries for building many different types of applications.

[45] Xamarin supplies add-ins to Microsoft Visual Studio that allows developers to build Android, iOS, and Windows apps within the IDE using code completion and IntelliSense.

Xamarin for Visual Studio also has extensions that provide support for the building, deploying, and debugging of apps on a simulator or a device.

[46] In late 2013, Xamarin and Microsoft announced a partnership that included further technical integration and customer programs to make it possible for their joint developer bases to build for all mobile platforms.

CEO and co-founder of Xamarin, Nat Friedman, announced the alliance at the launch of Visual Studio 2013 in New York.