The ESR is a central electronic database for qualified experts listed under the umbrella of the TRAIN4SUSTAIN standard. The database also provides different functionalities like a user interface and a match-making section (both also accessible via a mobile app from smartphones and tablets). The registry is the central instrument for comparing qualification schemes in the EU and for increasing the visibility of professionals. It provides an electronic interview mode for entering and evaluating existing qualifications schemes according to the new standard/framework and allows a self-classification and approval of skill levels for existing national qualifications (evaluation done by scheme operators). The registry also allows entering and displaying registered experts in terms of group of professional (e.g. designers, planners, blue-collar workers, facility managers, etc.), and their recognized skill level following the TRAIN4SUSTAIN competence quality standard. Private data usage fully consider all requirements of the EU General Data Protection Regulation (GDPR).