Cocos2d-x is an open-source game development framework that allows developers to create 2D games for multiple platforms, including iOS, Android, and Windows. It is based on the original Cocos2d engine and is written in C++, making it suitable for high-performance applications. The framework provides a rich set of features, including graphics rendering, physics simulation, and audio support. One of the key advantages of Cocos2d-x is its cross-platform capabilities, enabling developers to write code once and deploy it across various devices. It also supports scripting languages like Lua and JavaScript, allowing for flexibility in game design. With a strong community and extensive documentation, Cocos2d-x is a popular choice for indie developers and studios alike.