Solfec is a computational code aimed at simulation of constrained multibody systems on distributed memory parallel computers. It implements an instance of the Contact Dynamics (CD) method by Moreau and Jean, hence the constraints are handled implicitly. One of the main goals of the software is to provide a user friendly platform for testing formulations and solution methods for the (dynamic) frictional contact problem. It is also meant to serve as a development platform for other aspects of time-stepping methods (e.g. contact detection, time integration, kinematic models). The purpose of this communication is to outline the algorithmic ideas behind Solfec, with an emphasis on the Gauss–Seidel constraints solver, a classical element of CD, efficiently implemented on a distributed memory model. The remaining topics include a dynamic domain decomposition balancing the computational load of the overall algorithm, and an accuracy measure for the frictional contact constraints. Solfec is an open-source software and can be downloaded from http://code.google.com/p/solfec. Copyright © 2011 John Wiley & Sons, Ltd.