It is becoming more and more evident that the major hindrance to the proliferation and adoption of the MDA vision in the large is the current lack of tool support. Parallax, based on aspect-oriented support and through a well-defined system of plug-ins, addresses this issue by providing a framework that enables developers to incorporate middleware-specific concerns in their designs, and to view their enhanced designs through a prism of middleware platforms and see how middleware-specific concerns are actually implemented at the code level. Moreover, developers and middleware vendors can contribute and enrich Parallax by implementing and providing the community with new plug-ins for their favorite middleware infrastructures.