A typical qooxdoo application is created by leveraging the integrated development tools and the client-side programming model based on object-oriented JavaScript. Since no HTML, CSS nor DOM knowledge is needed, developers can fully concentrate on creating application classes without worrying about low-level cross-browser issues.

• qooxdoo runs in any modern web browser, including
  • Internet Explorer 6+
  • Firefox 2+
  • Opera 9+
  • Safari 3.0+
  • Chrome 2+
• No plugins required (neither ActiveX, Java, Flash nor Silverlight needed)
• Non-critical modifications of the native JavaScript objects to allow for easy integration with other libraries and custom code
• Cross-browser JavaScript 1.6 string/array generics

• Framework is fully class-based (currently about 350 classes)
• No pollution by global variables due to namespacing
• Besides regular classes, it offers abstract, static or singleton classes
• Constructors and destructors
• Public, protected and private members by naming convention, that can (partly) be enforced during development
• Single inheritance, full polymorphism
• Java-like interfaces
• Ruby-esque mixins
• So-called dynamic properties, a very convenient and powerful way to have optimized setter and getter methods generated from simple configuration

• Purely client-side JavaScript
• No HTML knowledge required
• No CSS knowledge required
• No DOM knowledge required
• Complete support for event-based programming
• Development of qooxdoo applications fully supported on all platforms, e.g. Windows, Linux, all Unixes, Mac OS X
• Quickstart for easy evaluation of the framework without the need to install any software
• Skeletons as pre-configured basis for full-featured custom applications
• Many sample applications and examples
• Designed for high performance
• Framework is memory-leak free
• Aid in developing memory-leak free user applications
• Extensive logging capabilities (e.g. different log appenders, Firebug support)
• Straightforward debugging (e.g. object introspection, benchmarking)
• Browser history management, i.e. browser back/forward button, bookmarks
• Cookies
• Generic JavaScript pretty printer / code formatter for unified code style

• Built-in internationalization (i18n) and localization (l10n) support
• Supporting all languages and locales, at least on this planet
• Based on the comprehensive Common Language Data Repository (CLDR)
• Internally using the mature GNU gettext tools
• Well-known translation file format (*.po)
• Support by professional, free translation tools (”po editors”) on all platforms

• Extended Javadoc-like source code comments
• Full API reference for both framework and custom application
• Online and offline API viewer application

• Integrated unit testing framework "Test Runner"
• Integrated functional testing framework "Simulator"

• Generation of a self-contained and easily deployable “build” version
• Complexity of the build process hidden behind user-friendly commands
• JavaScript compression (removal of whitespaces, etc.)
• Automatic dependency resolution of JavaScript classes; no need for manual “require” statements or tweaking a custom build
• Automatic linking of JavaScript classes (”JS linker”)
• Copying of required static resources like images or other external files into a self-contained build
• String extraction (tremendous performance improvement for IE6)
• Shortening and obfuscating local variables and/or private members
• Optional browser-specific variant for each supported browser (e.g. Firefox-only build)
• Generation of build versions depending on user-defined variants, which allows for different products from same code base
• Removal of debug statements within the application code before deployment

• Support for easy migration of custom applications from one framework release to another
• As painless as technically feasible
• Fully integrated into the regular build system
• All non-ambiguous changes are done automatically for maximum convenience and to avoid manual find/replace errors
• All ambiguous or semantic changes that require some developer decision are put into a comprehensive checklist

• Java/Eclipse: Eclipse Rich Ajax Platform (RAP)
• Java: qooxdoo Web Toolkit (QWT)
• PHP/Visual: Borland/CodeGear "Delphi For PHP"
• XML: XML-based GUI description