- Mono is the original cross-platform and open source .NET implementation, first shipping in 2004.
- It can be thought of as a community clone of the .NET Framework.
- The Mono project team relied on the open .NET standards (notably ECMA 335)
- Mono supports a subset of the .NET Framework app-models (for example, Windows Forms)
- Mono supports a large subset of the .NET Framework APIs, using the same assembly names and factoring.
- Mono supports many platforms and CPUs.
- Mono and .NET Core both use the MIT license and are .NET Foundation projects.
- The primary focus of Mono in recent years is mobile platforms, while .NET Core is focused on cloud and desktop workloads.