Parallel GAP: Mature interactive parallel computing Parallel GAP (ParGAP) is now a mature system to support parallel applications. No prior experience with parallel programming is needed in order to quickly develop new parallel applications. This article provides a description of some of the features of ParGAP that can greatly ease the challenge of writing a parallel program. As is true with standard GAP, ParGAP can be run in a completely interactive manner. This simple interactive usage is illustrated by a short program that implements “parallel streaming”, running distinct algorithms on the same problem, but under different processes. One then returns the first answer to be produced, and interrupts the other processes. This usage of ParGAP can be useful even on a single computer.