Mono

Mono provides an open‑source implementation of Microsoft’s .NET Framework that runs on multiple operating systems, including macOS, Linux, Android, and iOS. It follows the ECMA specifications for C# and the Common Language Runtime, allowing developers to compile and execute .NET applications without relying on Windows‑only runtimes. The project has been part of the .NET ecosystem since 2001 and is now stewarded by the WineHQ organization after Microsoft’s acquisition of Xamarin.

The platform targets developers who need to build or maintain cross‑platform .NET applications, especially those that must run on mobile devices, desktop Linux, or macOS environments. It offers a runtime and class libraries compatible with existing .NET code, enabling reuse of codebases across diverse hardware and operating systems.

Mono’s distinctiveness lies in its long history as the first .NET implementation on non‑Windows platforms and its continued open‑source development under the .NET Foundation. Documentation and source code are publicly available, and the community can contribute bug reports, patches, or new features. The project remains stable, with recent patch releases and binaries supported for several years.