ReactOS is a free and open-source operating system for x86/x64 personal computers intended to be binary-compatible with computer programs and devices. Developed by Aleksey Bragin
License: Open Source
ReactOS aims to be a free and open-source alternative to Windows, offering compatibility with Windows applications, while Haiku focuses on simplicity and efficiency, providing a modern experience inspired by BeOS. Both projects are open-source and lightweight, but they cater to different user needs and application ecosystems.