For 20 years, the German DINI Certificate for Open Access Publication Services has provided transparent criteria and guidelines for building and maintaining trustworthy publication services such as repositories and Diamond Open Access journals. The community-developed, non-commercial certificate paves the way for open scholarly communication and supports the prerequisites for the free availability of scholarly information as an essential element of future-oriented research-related services. Introduced in 2004 and now in its 7th revised version, the DINI Certificate has been used in approximately 120 - mostly successful - certification processes. Since the beginning the catalogue takes into account international standards (e.g. provided by COAR, OpenAIRE). With this poster, we are reaching out to the international repository community by illustrating the key features of the well-established Certificate and its catalogue of criteria. The latest version of the Certificate has been adapted to the Austrian legal system. We hope that other countries will follow, so that repositories in more countries can benefit from the DINI Certificate.