JavaFX is a set of tools and libraries for designing and creating graphically rich user interfaces for desktop, web, and mobile applications using the Java programming language. It provides a wide range of controls and layouts for creating visually appealing and interactive applications, as well as support for multimedia, animation, and 3D graphics. JavaFX is built on top of the Java platform and is part of the standard Java Development Kit (JDK). It is used by developers to build applications for various platforms including Windows, Mac, Linux, and mobile devices.