Mono is an open source implementation of .NET that runs on many platforms, including Linux, Mac OS X, and Windows. This allows running .NET applications on platforms other than Windows with little to no modification. Do NOT use this tag for questions about Java/Spring - use [spring]/[java] instead.
Mono, the open source development platform based on the .NET framework, allows developers to build Linux and cross-platform applications with improved developer productivity. Mono's .NET implementation is based on the ECMA standards for C# and the Common Language Infrastructure, but it also re-implements many Microsoft proprietary components like ADO.NET, WebForms, and WinForms.
Mono includes both developer tools and the infrastructure needed to run .NET client and server applications.
Since Microsoft open sourced .NET Core, the Mono repo has started to lose its importance in the ecosystem. Contribution to it fell significantly after 2020 and many reported issues remain opened.
Features:
Multi-Platform Runs on Linux, OS X, BSD, and Microsoft Windows, including x86, x86-64, ARM, s390, PowerPC and much more
Multi-Language Develop in C# 4.0 (including LINQ and dynamic), VB 8, Java, Python, Ruby, Eiffel, F#, Oxygene, and more
Binary Compatible Built on an implementation of the ECMA's Common Language Infrastructure and C#
Microsoft Compatible API Run ASP.NET, ADO.NET, Silverlight and Windows.Forms applications without recompilation
Open Source, Free Software Mono's runtime, compilers, and libraries are distributed under OSI approved licenses and are available for dual-licensing
Comprehensive Technology Coverage Bindings and managed implementations of many popular libraries and protocols
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