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Helping to realise the Once-Only Principle


Europe For All

Whats New at DE4A.EU?

October 2023:

Workshop for starting EBSI projects on DE4A reults.

On October 25, 2023 at 12:00 CET, DE4A organises a workshop primarily addressed to starting EBSI projects (VECTOR, EBSI-NE, TRACE4EU, ONEPASS), in order to communicate relevant DE4A outcomes for these projects. This initiative springs from a recommendation at DE4A final review to reach out to these projects under the Digital Europe Programme in order to organise a short workshop on relevant DE4A results to present the work done by DE4A, the outputs that are available for other projects to use and the lessons that DE4A has learned in the course of implementing its contract. Additionally, Atos sees a clear tie-in to work in DC4EU, a starting Large Scale Pilot also addressing a pilot in the education domain.

An overview of the topics of this workshop are:


  • Short introduction and overview of the technical components implemented related with self-sovereign identity, piloted and integrated with EBSI through the Early Adopters programme, with focus on cross-border recognition of university degrees. This focus facilitated the integration of public entities emitting these credentials, as well as the public entities providing services (receptors and verifiers of the credentials presented by the students in their wallets)

  • A demonstration of the pilot that validated the components.

  • Overview of main lessons learnt in the project and where to find the available resources (deliverables, code repository, etc) for further detailed information on the topics commented in the workshop.

Full information, agenda and registration


Recording of the workshop

September 2023:

EU eGovernment landscape: DE4A Summary report

The DE4A project has conducted extensive activities to provide overview and analysis of the EU eGovernment landscape. This report summarizes the key findings from the inventory activity, which focused on various aspects of eGovernment implementation, adoption and barriers. The activities revolved around identifying and analyzing the deployment of cross-border integrated Digital Public Services, as well as the status of existing solutions supporting Electronic Identification, Authentication and Trust services (including European Digital Wallets (eIDAS / eIDAS v2), the Single Digital Gateway Regulation (SDGR) and the Once Only Principle (OOP) implementation.
For a summary of the main findings, please consult the document "EU eGovernment landscape: DE4A Summary report"

July 2023:

DE4A, the project that has explored and piloted across borders to create an effective and efficient implementation of the once-only principle (OOP) for Member States, has come to an end after three years and four months.

On 24th May 2023, in the final review with the European Commission, the multidisciplinary results of the project were presented, addressing architectural, technical, semantic, legal and organisational barriers to cross-border interoperability in the context of the modernisation of EU public administrations (Once-Only Principle, Single Digital Gateway, Once-Only Technical System). Such results are expected to have a significant impact, making it much easier for Member States to meet the obligations resulting from the entry into force of the Single Digital Gateway Regulation. This Regulation requires that a list of 21 types of administrative procedures, currently available online to national users, be offered to cross-border users, with automated data exchange between public agencies, required to fulfil these procedures, e.g. applying for study grants, asking for recognition of academic titles or requesting proof of residence.


The main results have been the following:


  • Hands-on experience and knowledge for DE4A Member States: The project has provided the 8 participating Member States and other stakeholders with the necessary experience to address the short, medium and longer term challenges in the contexts of Once-Only, Single Digital Gateway and effective and integrated cross-border delivery of public services to citizens and businesses in the context of the modernisation of these public services across the EU.

  • DE4A Multipattern architecture for the cross-border exchange of evidence between the Member States.

  • DE4A Connector, the component that establishes the cross-border communication between the Member States for the exchange of evidences over an eDelivery network.

  • DE4A Self-Sovereign Identity Framework.

  • DE4A semantic components required for a common understanding to facilitate the cross-border exchange of information between public authorities.

  • Legal insights on the challenges for the implementation of the SDG.


The main results are released as open source and can be found, together with documentation and licensing information, on the DE4A Wiki and DE4A Github. Full information on project deliverables and academic publications can be found on the DE4A public deliverables and academic publications pages.

May 2023:

Ana Rosa Guzmán at OOTS Implementer's Café.

Ana Rosa Guzmán, Ministry of Economic Affairs and Digital Transformation (Spain) presented "DE4A, Multilingual Ontology Repository and User Interface" at the 5th OOTS Implementer’s café on May 5th 2023. See her presentation! 

DE4A launches its final newsletter!

Read all about the DE4A Final Event: descriptions of the sessions and lessons learnt, summary of testimonials and link to the Final Event microsite. Also: the latest takeaways from the legal and technical word packages, the status of the pilots, links to the resources released during the lifetime of the project and updates on the events we are participating in.

All ready to be shared!

April 2023:

DE4A held the DE4A Final Event (online, April 12th 2023) which provided an overview of the project's results and lessons learnt. Thank you to the speakers and attendees for an interesting event! You can find the presentations and useful links at the event microsite.

Project deliverables:

you can find the most recent documents in the deliverables section:

DE4A D2.8 Beyond Interoperability One Network for Europe (ONE)

DE4A D4.8 Doing Business Abroad - Final Running Phase Report

DE4A D7.4 Report on Legal Sustainability

March 2023:

DE4A is honoured to invite you to the DE4A Final Event (online, April 12th 2023) which will provide a quick, easy-to-understand overview of the project's results and lessons learnt. Find out more about the agenda and register here.

February 2023:

DE4A at the Austrian IRIS symposium

IRIS symposium is an Austrian conference for legal informatics, in which eGovernment is also included in the conference programme. The conference takes place yearly in Salzburg/Austria. In the 2023 Austrian consortium consisting of BRZ/BMF, which is also involved in DE4A, explained Austrian findings and experience regarding Once Only Principle in the Single Digital Gateway Regulation (project, processes, architecture, environment and influence factors).

DE4A was part of the presentation at IRIS symposium, as an influence factor for the SDG Once Only realisation in Austria. The presentation took place on 23. February 2023 in the session "eGovernment I"; around 20 persons were in the audience (offline and online).

DE4A Moving Abroad pilot, mission accomplished


The DE4A Moving Abroad pilot has been working for some time. Now we have two countries live with pilot services (Spain and Slovenia) for the use case enabling to request an extract or copy of civil status (Birth and Marriage) certificates. Slovenia (data provider) is providing both types of certificates to the Spanish online citizen portal (data consumer). Additional cross-border combinations also involving Luxembourg, Romania and Portugal will soon be launched also for registering a change of domicile address (with subsequent deregistration of an old domicile address in the case of Portugal).

Read the full story 

DE4A pilot Doing Business Abroad, successfully completed

Sweden, Romania, Austria and The Netherlands have successfully completed the Doing Business Abroad pilot as part of the DE4A Large Scale Pilot.

The Member States have developed international infrastructures to support cross-border activities for companies. These have been integrated with business registers and public authorities providing services for companies and have enabled public authorities to stay informed about any events that occur in the company, so they can make sure to provide the correct services.

In a situation without the infrastructure, registering a new business activity can take up to several weeks and requires obtaining documented proof that must be uploaded or sent per email. See the full story

January 2023:

Service Interoperability Solutions Toolbox: DE4A wiki, now available.

In the technical work packages of DE4A, as well as in the technical task team and in DE4A participating organizations, different levels and types of specifications and documentation have been created during the project.

This process is fraught with the risk that project documentation becomes scattered, and structuring attempts are more often than not too late to be effective.

To prevent this, and as a part of WP2 Architecture Vision and Framework tasks, DE4A has produced a deliverable aimed at maintaining an orderly overview and thus maximizing the value of all the specifications, guidelines, etc. that work packages produce.

Moreover, this toolbox has been given the form of an online wiki, making publicly available relevant documentation such as DE4A interaction patterns, common components or pilots.

Launch of services in the final phase of the Studying Abroad pilot

The Studying Abroad pilot of the DE4A project aims at demonstrating in practice the benefits for students and competent authorities of realizing across borders the principles of Once-Only and digital-by-default. The pilot is proud to announce that several cross-border educational services have been launched for the final pilot phase. Find all the information at the Studying Abroad Pilot microsite.

Doing Business Abroad microsite updated.

The updates include two new videos on cross-border scenarios: Romanian companies registering in The Netherlands, and Dutch companies registering in Germany. Doing Business Abroad Pilot page.


December 2022:

DE4A has launched its sixth newsletter.

In this brand-new edition, you will find information on the Dutch-Germany cross-border pilot, that has counted on external collaboration with German entities; the latest developments in the work carried out with semantics, and new updates on the Member State baseline survey.


November 2022:

DE4A are pleased to announce that the collaboration on the Results in Brief article as part of the Results Pack on Social Innovation has been now published on the CORDIS website in six languages at:

Digital tools to support the free movement of data in the EU


The full Results Pack can be found here:
Creative solutions to Europe’s challenges through social innovation


October 2022:
DE4A presents at the ICEGov
Digital Governance for Social, Economic, and Environmental Prosperity conference in, Guimarães, Portugal. Read about it
here (in Spanish) or here in English

Course: European Interoperability Framework (EIF) & Core Public Service Vocabulary (CPSV)
The international Hellenic University (IHU) has developed a free and open online course on the European Interoperability Framework (EIF) & Core Public Service Vocabulary (CPSV) as part of the dissemination of the project. View more.

DE4A Deliverable 2.7
"Interoperability Architecture for Cross-border Procedures and Evidence Exchange in light of the Single Digital Gateway Regulation" has now been submitted, and is available to view

Click here to view deliverables

September 2022:

Press release 
DE4A and GLASS Collaborate to Deliver Greater Efficiencies for the European Commission and Improved Services for EU Citizens 

Click here to view

EEMA Fosters Cross-Project Collaboration for EU Funded Initiatives (1) - Copy.png

September 2022:
DE4A is excited to announce the newest website page highlighting the latest project academic publications.  

Click here to view

September 2022:

Digital Europe for All (DE4A) collaborates with the GLASS Project

Click here for more info.

June 2022:
See Digital Europe for All (DE4A)'s latest newsletter. 

Click here for more info.

May 2022:
Digital Europe for All (DE4A) Launches Studying Abroad Pilot. 

Click here for more info.

February 2022:

November 2021: The DE4A "Studying Abroad" Pilot micro-site is now live. Find all you need to know about being involved in the Studying Abroad Pilot! here.

September 2021: The DE4A "Doing Business Abroad" Pilot micro-site is now live. Find all you need to know about being involved in the DBA Pilot! here.

April 2021: All the latest DE4A deliverables can be found  here.


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 European Interoperability Framework Implementation Strategy and with full regulatory compliance, 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.

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DE4A High Level Explainer
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DE4A Explained


Special attention has been given to the composition of the consortium in order to achieve a good balance that makes sure that all goals of DE4A can be achieved. Thus, the project has followed a purposeful, multidisciplinary approach in establishing the Consortium.

DE4A includes 22 partners, including 8 Member States, (Austria, Luxembourg, Netherlands, Portugal, Romania, Slovenia, Spain, and Sweden).


DE4A has a duration of 40 months, starting on January 1st 2020 and running through April 2023


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