I’ve written a couple articles elsewhere (1, 2) about what I see to be the next evolutionary step for RIA platforms: The Fit Client. A Fit Client Platform combines the capabilities of fat clients for the desktop with widget engines and RIA to provide a full-featured runtime that is portable across operating systems. There are a number of examples of these kinds of platforms including Java Web Start, Adobe AIR, Curl Nitro, and to a lesser extent Google Gears.

I recently read an article on ars technical about how Nokia, a supporter of Webkit and future home of Trolltech is helping port Firefox to Trolltech’s own Fit Client technology called Qt. You may never have heard of Qt but its been used to develop a lot of stuff you probably have on your desktop like Google Earth, Skype, Adobe Photoshop Album, Opera web browser, and the popular KDE Linux desktop. Qt is quietly seeping into a lot the GUI applications we use on a daily basis.

Like Java, Adobe AIR and Curl Nitro, Qt provides a substantial set of APIs and GUI components that can be used across operating systems. In fact, Qt supports more operating systems than any other Fit Client Platform including Windows, Mac OS X, Linux /X11, Windows CE, and Embedded Linux. I’ll go out on a limb and predict that Qt will be ported to Nokia’s Symbian operating system as well.

What makes Qt interesting is not only its established track record in free an commercial software, but its lineage which dates back to 1991 making Qt more mature than any other Fit Client Platform including Curl and Java both of which are over a decade in the making. Another thing that makes Qt interesting is that Qt applications are written in C++.

Nokia’s interest in creating a viable competitive platform across mobile operating systems and the fact that Nokia is going to own Qt - as much as any commercial entity can own a dual licensed product -its not a big leap to see the potential of Qt as the foundation for a C++ RIA platform. If both Firefox and WebKit support Qt, it makes sense to extend Qt from a Fit Client to a RIA plug-in. Lest we forget, WebKit is the foundation of both Apple Safari and Opera is written in Qt. That would be a reverse of the evolutionary model of other Fit Client Platforms which started out as RIAs and evolved into Fit Clients.

It’s going to be interesting to see where Nokia takes Qt - they could be the Daddy Warbucks Qt needs to become a dominate player in the Fit Client Platforms arena - but its also possible that Nokia will add little or no value or that it might eventually abandon Qt all together. Time will tell but I’m betting that Qt will become more pervasive as Nokia extends its reach to new platforms and new deployment models including RIA.

Read more from Richard Monson-Haefel.