TOOP Pilot Experiences: Challenges and Achievements in Implementing Once-Only in Different Domains and Member States

Abstract The Once-Only Principle (OOP) enables public administrations to support citizen and business life-cycle oriented issues as opposed to mere integration of administrative systems designed to serve bureaucratic ends. The Once-Only Principle project (TOOP) was funded by the EU Program Horizon 2020, with the aim to explore and demonstrate the OOP through multiple sustainable pilots in different domains, using a federated architecture on a cross-border collaborative pan-European scale, enabling the connection of different registries and architectures in different countries for better exchange of information across public administrations. The different pilot domains (eProcurement, Maritime and General Business Mobility) identified potential use cases suitable to show the OOP, defined the goals and expected benefits of TOOP based on motivational scenarios and process analyses and provided requirements to the TOOP Reference and Solution Architectures. Especially for the General Business Mobility domain requirements were provided also from the Single Digital Gateway Regulation. These requirements guided the development of the TOOP specifications and the TOOP components, the Member States deployed the TOOP specifications and components and participated in different connectathons demonstrating the OOP.