For a completely working Digital Single Market, effectively enabling the cross-border exercise by citizens and businesses of their Single Market rights, Member States must address several challenges on delivering better services. DE4A is a Member State-driven pilot, aligned with strategic eGovernment Action Plan 2016-2020 and EIF Implementation Strategy and with full regulatory compliance (SDGR, GDPR, eIDAS, Services Directive…), establishing a culture of co-creation, transparency, accountability and trustworthiness. Its goal is facilitating migration towards European Digital Public Services co-delivered across borders, across sectors and with different participants, reinforcing trust in public institution, and unleashing multiple measurable positive impacts on efficiency gains and reduction of administrative burden and costs. Starting from needs and capacities of Member States, DE4A’s scalable, holistic, flexible approach focuses on high-quality fully online procedures accessible through the SDG by building on an extended interoperability Toolbox and on state-of-the-art. It enables an open and comprehensive environment and platform for collaboration and innovation, leveraging common eGov baseline patterns for secure, privacy-preserving and trustworthy realisation of essential Once-Only and Relevant-Only principles, and with re-use of existing and new building blocks and Digital Service Infrastructures at national and EU-wide levels. Innovative technologies like blockchain, machine learning, self-emerging ontologies and zero-knowledge proofs will be addressed for effective sharing of common services. Pilots involving secure access to key administrative procedures of real life and business events, shall highlight aspects of the technical ecosystem available for the SDG implementation, prove their technical viability and gauge the performance and degree in which non-functional requirements can be accommodated. DE4A includes 23 partners and has a duration of 40 months.