You leverage its integrated tool chain to develop and deploy applications of any scale, while taking advantage of a comprehensive feature set and a state-of-the-art GUI toolkit. qooxdoo is open source under liberal licenses, run by one of the world's leading web hosts 1&1, with a vibrant community.
No HTML has to be used and augmented to define the interface. The qooxdoo developer does not even have to know CSS to style the interface. Clean and easy-to-configure themes for appearance, colors, borders, fonts and icons allow for a full-fledged styling.
While being a client-side and server-agnostic solution, the qooxdoo project includes different communication facilities, and supports low-level XMLHttpRequests (XHR) as well as an RPC API. An abstract transport layer supports queues, timeouts and implementations via XHR, Iframes and Scripts. Like the rest of qooxdoo it fully supports event-based programming which greatly simplifies asynchronous communication.