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