Rich Internet Applications

Rich Internet applications (RIAs) are web applications that have some of the characteristics of desktop applications, typically delivered by way of a proprietary web browser plug-ins or independently via sandboxes or virtual machines. Examples of RIA frameworks include Adobe Flex/AIR, Java/JavaFX and Microsoft Silverlight.

The term was introduced in the 1990s by vendors like Macromedia who were addressing limitations at the time in the "richness of the application interfaces, media and content, and the overall sophistication of the solutions" by introducing proprietary extensions. As web standards (such as Ajax and HTML 5) have developed and web browsers' compliance has improved there is less need for such extensions, and Javascript compilers with their associated desktop-like widget sets reduce the need for browser extensions even further.

HTML 5 delivers a full-fledged application platform; "a level playing field where video, sound, images, animations, and full interactivity with your computer are all standardized". It is now possible to build RIA-like Web applications that run in all modern browsers without the need of special run-times or plug-ins. This means that if one could run a modern Ajax-based Web application outside of a web browser (e.g. using Mozilla Prism or Fluid) it would essentially be an RIA, though there is some contention as to whether this is actually the case.