The Data Seal of Approval (DSA) and the International Council for Science’s World Data System (ICSU-WDS) have both developed core certification standards for trustworthy digital repositories and offer their own certification services. However, whilst the DSA and WDS core certifications standards evolved independently, their catalogues of criteria and their review procedures are based on the same principles of openness, transparency, and striking the right balance between the simplicity and robustness of the work and effort involved. A DSA–WDS Partnership Working Group (WG) was initiated under the umbrella of the Research Data Alliance (RDA) with the objectives of realizing efficiencies, simplifying assessment options, stimulating more certifications, and increasing impact on the community. The WG delivered a harmonized DSA–WDS Catalogue of Common Requirements for core certification of repositories, as well as a set of Common Procedures for their assessment. This unified certification standard will be adopted by the two organizations, and integrated into relevant tools and systems, before the end of 2016.