Transparency and access to information are critical for the European energy efficient and sustainable buildings market. Construction, building occupation/management, transactions and investment and financing decisions heavily rely on transparent data availability. Limited information availability and lack of a common digital data repository increase costs and inefficiencies in designing, constructing, operating and financing buildings. The CEAP recognises Digital Building Logbooks as circularity enablers and the Renovation Wave states that DBLs will integrate all related data from upcoming building renovation passports, smart readiness indicators, Level(s) and EPCs. Demo-BLog brings together: (i) 5 different DBLs with a total of 4.5 million registered units and a wide variety of target groups (homeowners, municipalities, building professionals and architects) offering scale and diversity; (ii) 4 diverse functionalities addressing key societal challenges, ranging from ‘quick wins’ (renovation and advice and (community driven) decarbonisation pathway) to complex industrial transaction objectives (circularity); (iii) partners, frontrunners in R&D, policymaking and market implementation in highly visible platforms over the last 5 years and (iv) substantial opportunities to build and leverage parallel projects and activities focussed on evolving/scaling the participating building logbooks. The DBLs demonstrated in this project have the potential to eventually reflect the whole lifecycle with a capacity for unlimited data access, input and output, and data export. They are also capable of embracing future technological developments, such as widespread use of BIM, IoT, digital twins and blockchain. Demo-BLog has considerable potential to optimise the use of resources and waste, performance prediction, visual analytics and energy management contributing to the overall goal of “making Europe the first digitally led circular, climate neutral and sustainable economy”