Over the past years several users (in Belgium, the Netherlands and abroad) have adopted the ESAT speech recognition software package (developed for over 15 years at ESAT, K.U.Leuven, [5, 10]) as they found that it satisfied their research needs better than other available packages. However, typical of organically grown software, the learning effort was considerable and documentation lacking. The software needed a major overhaul and this is accomplished with support from the STEVIN programme and a partnership consisting of Katholieke Universiteit Leuven, Radboud University Nijmegen, Twente University and TNO. At the same time the main weaknesses were addressed and the code base was modernised. This effort also addressed the need of the research community for a Dutch speech recognition system that can be used by non-specialists. We also found this to be an ideal moment to open up the code to the community at large. It is now distributed as open source for academic usage and at moderate cost for commercial exploitation. The toolkit, its documentation and references can be found at http://www.spraak.org. In this article details of the SPRAAK toolkit are given in several sections: Sect. 6.2 discusses the possible uses of the toolkit, Sect. 6.3 explains the features of the different components of the software, some benchmark results are given in Sect. 6.4, system requirements of the software are mentioned in Sect. 6.5, licensing and distribution is covered in Sect. 6.6, relation to other STEVIN projects in Sects. 6.7 and 6.8 addresses future work. Finally a conclusion is given in Sect. 6.9. This article tries to give as complete information as possible about SPRAAK and is therefore targeted at several audiences: