Effective groupware toolkits not only make it possible for average programmers to develop groupware, but also enhance their creativity. By removing low-level implementation burdens and supplying appropriate building blocks, toolkits give people a ‘language’ to think about groupware, which in turn allows them to concentrate on creative designs. This is important, for it means that programmers can rapidly generate and test new ideas, replicate and refine ideas presented by others, and create demonstrations for others to try. To illustrate the link between groupware toolkits and creativity, I describe example toolkits we have built and how others have leveraged them in their own work.