RubyMine is an integrated development environment (IDE) for the Ruby programming language, developed by JetBrains. It provides a wealth of features to help Ruby developers write, debug, and test their code more efficiently. Some key features of RubyMine include syntax highlighting, code completion, refactoring tools, debugger, and integration with version control systems. It also supports Ruby on Rails, Sinatra, and other popular Ruby frameworks. RubyMine is available for Windows, macOS, and Linux operating systems.