The Once-Only Principle: A Matter of Trust.- Implementation of the 'once-only' principle in Europe – national approaches.- Drivers for and Barriers to the Cross-Border Implementation of the Once-Only Principle - Once-Only Principle Good Practices in Europe.- The Single Digital Gateway Regulation as an Enabler and Constraint of Once-Only in Europe.- Legal Basis and Regulatory Applications of the Once-Only Principle: the Italian Case.- TOOP Trust Architecture.- The Technical challenges in OOP application across the European Union and the TOOP OOP architecture.- Testing methodology for the TOOP pilots.- TOOP pilot experiences: challenges and achievements in implementing once-only in different domains and Member States.- Measuring the Impact of the Once Only Principle for Businesses Across Borders.- The Future of the Once-Only Principle in Europe.

This open access State-of-the-Art Survey describes and documents the developments and results of the Once-Only Principle Project (TOOP). The Once-Only Principle (OOP) is part of the seven underlying principles of the eGovernment Action Plan 2016-2020. It aims to make the government more effective and to reduce administrative burdens by asking citizens and companies to provide certain standard information to the public authorities only once.The project was horizontal and policy-driven with the aim of showing that the implementation of OOP in a cross-border and cross-sector setting is feasible. The book summarizes the results of the project from policy, organizational, architectural, and technical points of view.This book has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 737460

This book is open access, which means that you have free and unlimited access It describes and documents the developments and results of the Once-Only Principle project (TOOP) The TOOP project was funded by the EU Framework Programme for Research and Innovation

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