Adobe Flex is a software development kit (SDK) released by Adobe Systems for the development and deployment of cross-platform rich Internet applications based on the Adobe Flash platform. Flex applications can be written using Adobe Flash Builder or by using the freely available Flex compiler from Adobe.
Define an application interface using a set of pre-defined components (forms, buttons, and so on) . Arrange components into a user interface design . Use styles and themes to define the visual design . Add dynamic behaviour (one part of the application interacting with another, for example). Define and connect to data services as needed.
Flex is a free, open source framework for building highly interactive, expressive web applications that deploy consistently on all major browsers, desktops, and operating systems.