Flex is a highly productive, free open source framework for building and maintaining expressive web applications that deploy consistently on all major browsers, desktops, and operating systems. While Flex applications can be built using only the free Flex SDK, developers can use Adobe® Flex® Builder™ 3 software to dramatically accelerate development.

Flex Builder 3™ offers powerful new capabilities for creating rich Internet applications (RIAs)
* Full support for Adobe AIR makes it easy to create RIAs for the desktop
* New integration with Adobe Creative Suite™ 3 helps designers and developers to work together more efficiently
* New and enhanced data visualization features, including the new advanced datagrid, enable even richer presentation of business data
* New memory and performance profilers make it easy to optimize your application