JetBrains Rider is a cross-platform .NET IDE (integrated development environment) developed by JetBrains. It provides development tools for .NET framework, .NET Core, and Xamarin, and supports various programming languages such as C#, F#, Visual Basic .NET, and more. Rider offers advanced code editing, debugging, and refactoring features, as well as integration with popular version control systems and build tools. It also includes support for front-end technologies such as JavaScript, TypeScript, HTML, and CSS. Rider is available for Windows, macOS, and Linux operating systems.