Certification of software artifacts offers organizations more certainty and confidence about software. Certification of software helps software sales, acquisition, and can be used to certify legislative compliance or to achieve acceptable deliverables in outsourcing. In this article, we present a software product certification model. This model has evolved from a maturity model for product quality to a more general model with which the conformance of software product artifacts to certain properties can be assessed. Such a conformance assessment we call a ‘software product certificate’. The practical application of the model is demonstrated in concrete software certificates for two software product areas that are on different ends of the software product spectrum (ranging from a requirements definition to an executable). For each certificate, a concrete case study has been performed. We evaluate the use of the model for these certificates. It will be shown that the model can be used satisfactorily for quite different kinds of certificates.