Ukraine does not have a reliable and publicly available source of information and data about protected areas (PAs). Therefore crowdsource development of the open cadastre of PAs was jointly initiated by non-governmental organizations activists, GIS-specialists, conservation researches and practitioners. As a result, primary data has been collected for all regions of Ukraine, and for 10 of them the process of borders digitizing and data import into the OpenStreetMap (OSM) has been started. Alpha-version of the online service for the rapid data access and validation has been launched and available from WebApp.