Discover everything you need to know about the Once-Only Technical System.
Moving forward, when completing administrative procedures abroad, citizens and
businesses no longer need to search for their official documents.
With the Once-Only Technical System (OOTS), public authorities can exchange
verified data directly at citizens' request, reducing paperwork and making
cross-border admin faster, cheaper and more reliable.
Save time and money on cross-border services. Work more efficiently with trustworthy, real-time data. Gains mobility, competitiveness, and cohesion across Member States. The numbers behind the Once-Only Technical System.
Take a look at how the European Union has been implementing the OOTS with the Acceleratormeter.
Read how Member States and Authorities have been implementing OOTS, and get involved through our Projectathons and future local events.
data exchange
The Once-Only Technical System:
Simplifying cross-border
data exchange
The EU infrastructure enabling secure, seamless cross-border data exchange between public authorities.
Freedom to move, work, and study without the paperwork
The Once-Only Technical System can benefit everyone in the Single Market
Citizens & Businesses
Public Administrations
The European Economy
Many procedures, one effortless experience
Unlock tomorrow with Once-Only today
Implementation tracker
Join our events
Latest news
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Workshop brings the Western Balkans closer to Europe’s Single Digital Gateway (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/956171065/illu-news-oots-18-03-2026.jpg
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March 2026 European Council stresses competitiveness and the importance of the Single Market (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/956172479/illu-news-oots-25-03-2026.jpg
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National coordinators meet during the 59th SDG coordination group meeting (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/956171803/illu-news-oots-23-03-2026.jpg
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The Once-Only view from Finland (OOTSHUB) —FinlandKirsi Mikkonen - Mervi Kylmänen-Paakki - Olli Hurskainenhttps://ec.europa.eu/digital-building-blocks/sites/download/attachments/674509304/interview-card-cover-finland.jpg
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The Once-Only view from France (OOTSHUB) —FranceJonathan J. AttiaFrench CTO for European Single Digital Gatewayhttps://ec.europa.eu/digital-building-blocks/sites/download/attachments/631047320/interview-card-cover-france.jpg
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The Once-Only view from Portugal (OOTSHUB) —PortugalJorge SousaPortuguese national coordinator for European Single Digital Gatewayhttps://ec.europa.eu/digital-building-blocks/sites/download/attachments/652773269/interview-card-cover-portugal.jpg
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The Once-Only view from Germany (OOTSHUB) —GermanyChristoph Harnoth - Sybille Behlinghttps://ec.europa.eu/digital-building-blocks/sites/download/attachments/694486760/interview-card-cover-germany.jpg
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Watch Once-Only Studio interview with Croatian SDG team (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/924975280/interview-card-cover-portugal.jpg
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Directorate General for Higher Education officially becomes Once-Only evidence provider (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/924975150/illu-news-oots-13-10-2025.jpg
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Competitiveness is at the top of the EU’s agenda: why “Once-Only” is essential (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/947486842/illu-news-oots-05-02-2026.jpg
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2025 sees EU step up efforts for a simpler and more competitive Single Market (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/956170244/illu-news-oots-13-03-2026.jpg
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Once-Only Services going-live! SDG procedures in production in Croatia (setting up a business, doing an income tax return and applying for studies) (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/952468703/illu-news-oots-02-03-2026.jpg
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Commission releases version 2.0 of the OOTS Technical Design Documents (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/952471419/illu-news-oots-05-03-2026.jpg
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SDG national coordinators discuss the road ahead in first OOTS Coordinators Café (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/946733242/illu-news-oots-04-02-2026.jpg
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"Once-Only" steers Europe towards simpler cross-border processes for a better Single Market, in line with the EU Competitiveness Compass (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/881983974/illu-news-oots-07-02-2025.jpg
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Watch Once-Only Studio interview with Finnish SDG team (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/891322871/illu-news-oots-08-04-2025.jpg
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Austria talks about synergies between "Once-Only" and the EUDI Wallet (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/905219262/illu-news-oots-08-07-2025.jpg
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Digital Commission Awards: Once-Only wins for Team demonstrating the most multidisciplinary approach for digital-ready policymaking (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/887382196/illu-news-oots-19-03-2025.jpg
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Re-live ‘Europe goes Once-Only – Lithuania edition’ – aftermovie! (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/902433610/illu-news-oots-16-06-2025.jpg
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Once-Only Studio presents: a conversation with Lithuania (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/909707471/illu-news-oots-07-08-2025.jpg
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Watch Once-Only Studio interview with Spanish SDG team (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/920060264/illu-news-oots-16-09-2025-cta.jpg
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Re-live ‘Europe goes Once-Only - Portugal edition’ with the official aftermovie (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/924977246/illu-news-oots-31-10-2025.jpg
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Your Europe celebrates five years of free, accurate information and support for your life and business in the EU (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/935395782/illu-news-oots-16-12-2025.jpg
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From Once-Only Principle to the EU Digital Identity Wallet: how Europe is simplifying digital public services (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/940311615/illu-news-oots-18-01-2026.jpg
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Finnish SDG Team Present Nordic-Baltic OOTS 2.0 project at SEMIC 2025 (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/930453289/illu-news-oots-08-12-2025.jpg
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Once-Only Services going-live! Change of competent authority for air traffic controllers in Italy (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/935396425/illu-news-oots-18-12-2025.jpg
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Two systems one vision: OOTS-EUDI Wallet synergies final report published (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/930453293/illu-news-oots-09-12-2025.jpg
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OOTS go-live announcement – Lithuania (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/930449095/illu-news-oots-25-11-2025.jpg
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“Europe Goes Once-Only – Croatia edition” brings a simpler Single Market to the southeastern EU (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/930451374/illu-news-oots-01-12-2025.jpg
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Commission Publishes 2026 Work Programme, Driving Forward Simplification Agenda (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/929202632/illu-news-oots-10-11-2025.jpg
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“Quality of Public Administration Toolbox for Practitioners” recommends Once-Only to EU Member States (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/929202440/illu-news-oots-10-11-2025.jpg
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OOTS Community meets during 17 Implementers Café (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/924976619/illu-news-oots-27-10-2025.jpg
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October 2025 European Council calls for Simplification to lead EU Competitiveness Agenda (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/924976587/illu-news-oots-24-10-2025.jpg
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Updates to Once-Only ‘Acceleratormeter – Portugal and Latvia progress (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/924975703/illu-news-oots-17-10-2025.jpg
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How “Once-Only” is at the heart of a ‘28th Regime’ in the EU’ (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/920064190/illu-news-oots-03-10-2025.jpg
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“Europe goes Once-Only – Portugal Edition" accelerates integration of national Competent Authorities, September 2025 (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/920063611/illu-news-oots-01-10-2025.jpg
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Once-Only Services going-live! Applying for a tertiary education study financing in Finland (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/920060755/illu-news-oots-25-09-2025.jpg
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Dutch national coordinator publishes OOTS Common Services Query Validator (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/920063579/illu-news-oots-01-10-2025.jpg
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State of the EU 2025: a more competitive Europe in testing times (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/915933156/illu-news-oots-12-09-2025.jpg
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16th OOTS Implementers' Café Webinar Sets the Stage for Upcoming Conferences in Lisbon and Zagreb (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/915933183/illu-news-oots-12-09-2025-ic16.jpg
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Tuesday 26th of July - Live Webinar: "CEF eDelivery - What's In It For You?" (Digital) — Thank you to all who attended the webinar. We hope it proved useful in clarifying your understanding. For those of you who couldn't attend, or who wish to re-listen, below you will find recordings of each segment of the webinar.
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The challenge of implementing modern Cloud infrastructure Lessons from the Once-Only Common Services Cloud experience (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/915931574/illu-news-oots-28-08-2025.jpg
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Recent event “Towards a Simpler Single Market” sings praises of the Once-Only Technical System (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/908526049/illu-news-oots-16-07-2025-1.jpg
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Commission publishes event report for the #6 Once-Only Technical System Projectathon (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/908525670/illu-news-oots-14-07-2025.jpg
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Member States debrief #6 Once-Only Technical System Projectathon and prepare the next ‘Europe goes Once-Only’ event in Portugal (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/905217281/illu-news-oots-01-07-2025.jpg
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EU Member States move towards live transactions in sixth OOTS Projectathon (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/902433564/illu-news-oots-16-05-2025.jpg
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Commission organises webinar on building a sovereign and secure digital future – How DIGIT can help you become a digital innovator (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/900015970/illu-news-oots-23-05-2025.jpg
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First Version of Once-Only Technical System goes into Production in Finland (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/896827582/illu-news-oots-06-05-2025.jpg
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Once-Only means a simpler, more resilient digital environment in Europe (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/892470445/illu-news-oots-16-04-2025.jpg
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Member States take stock between milestone events in #14 OOTS Implementers Café (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/894304673/illu-news-oots-24-04-2025.jpg
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Major success as Member States and Competent Authorities gather in Vilnius, Lithuania (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/894304266/illu-news-oots-18-04-2025.jpg
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Citizen forums show how the Once-Only Technical System can save students time and money (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/887384412/illu-news-oots-01-04-2025.jpg
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Once-Only goes local, 2025 (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/887383475/illu-news-oots-27-03-2025.jpg
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Lithuania prepares to roll out the Once-Only Technical System (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/887381888/illu-news-oots-18-03-2025.jpg
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General Report on the Activities of the EU 2024 shows value of “Once-Only” (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/887381485/illu-news-oots-14-03-2025.jpg
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Germany progresses on national-Once-Only Technical System (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/887380245/illu-news-oots-06-03-2025.jpg
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How Europe will go “Once-Only” in 2025 – updates from 13th Implementers’ Café (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/883824996/illu-news-oots-20-02-2025.jpg
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2025 Commission work programme puts simplification in the spotlight (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/883824247/illu-news-oots-17-02-2025.jpg
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Register now: Europe goes Once-Only - Lithuania edition (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/881983883/illu-news-oots-06-02-2025.jpg
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Gateway Coordination Group discusses Once-Only in the year ahead (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/881983728/illu-news-oots-05-02-2025.jpg
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Commission launches development of new Technical Support Dashboard (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/875855875/illu-news-oots-24-01-2025.jpg
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Single Market Strategy 2025 Call for evidence January 2025 (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/864335488/illu-news-oots-07-01-2025.jpg
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eDelivery Interoperability Forum (19 March 2026) (eDelivery User Community) —
19 March 2026 | 10:30-12:30
eDelivery Interoperability Forum Meeting
We gave you an update on the profile specifications changes in 2025 and preview what was next when it comes to eDelivery profiles 2.0 adoption. Sign up if you are not yet a member of our forum of eDelivery solution providers.
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eDelivery Informal Cooperation Network Meeting (Q3 2026) (eDelivery User Community) —
Q3 2026 | full day
13th meeting of eDelivery Informal Cooperation Network
The ICN is a platform for Member States representatives who are involved in the set-up of national eDelivery infrastructures to actively contribute to the adoption of eDelivery at national and EU levels. The aim of the meeting is to promote knowledge sharing, enable collaborative work on cross-border eDelivery networks and facilitate discussion about common challenges.
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eDelivery Interoperability Forum (3 May 2023) (eDelivery User Community) —
03 May 2023 | PAST EVENT
eDelivery Interoperability Forum
After more than two years since its last edition, the eDelivery team will relaunch the Interoperability Forum in May 2023.
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eDelivery Interoperability Forum (27 June 2023) (eDelivery User Community) —
27 June 2023 | Past event
eDelivery Interoperability Forum
After more than two years since its last edition, the 2nd meeting of eDelivery Interoperability Forum is taking place.
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eDelivery Interoperability Forum (29 February 2024) (eDelivery User Community) —
29 February 2024
eDelivery Interoperability Forum: updated eDelivery 2.0 profiles
Collaboration between eDelivery and software and service providers continues in 2024. We discussed the disposition of review comments resulting from the recent public consultation, and presented the updated versions of the eDelivery profiles.
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eDelivery Interoperability Forum (28 November 2023) (eDelivery User Community) —
28 November 2023 | Past event
eDelivery Interoperability Forum
The eDelivery Interoperability Forum members met for the third time this year to discuss an update to the results of the public consultations on changes in specifications, eDelivery's contribution to third-party open-source projects, and opportunities from digital ecosystems such as eFTI Exchange Environment.
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eDelivery Interoperability Forum (18 April 2024) (eDelivery User Community) —
18 April 2024
eDelivery Interoperability Forum: AS4-conformant solutions
In the second community meeting this year, we focused on the eDelivery AS4-conformant solutions and their new listing on our website. To keep this relevant, dear product and service vendors, please share updated information about your software.
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How-to video on Domibus 5.1 and 5.2 new features (Q1 2026) (eDelivery User Community) —
Q1 2026
How-to video on Domibus 5.1 and 5.2 new features
The "new features in Domibus 5.1 and 5.2" how-to video will guide the users through the new features of Domibus, which is the sample implementation of an eDelivery Access Point maintained by the European Commission.
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Introducing Domibus 5.2 & 5.1 (3 March 2026) (eDelivery User Community) —
3 March 2026 | 14:00-16:00
Introducing Domibus 5.2 & 5.1
Join this webinar to learn about the new features in Domibus 5.2 and 5.1. Ask your questions and share feedback.
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CEF Building Blocks Presented at Internet of Things (IoT) World Congress 2018 (Digital) — The current lack of ICT platform standards to manage such information means an obstacle for the development of Smart Digital Services.
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Connecting Europe: CEF Building Blocks Presented at eDelivery Day in Sweden (Digital) — Sweden has made significant progress in the deployment of eDelivery infrastructure at the creation of a vibrant digital ecosystem around it.
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CEF Building Blocks Presented at the Swedish Conference eFÖRVALTNINGSDAGARNA (Digital) — The event ran over two days, filled with the latest information regarding e-government and digital transformation.
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CEF Building Blocks Presented at the German Federal Office of Administration (Digital) — The BVA has a history of close cooperation with the European Commission, and Member States' authorities.
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CEF eInvoicing and eDelivery presented at the Exchange Summit in Berlin (Digital) — The European Commission presented eInvoicing at the Exchange Summit in Berlin
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Lithuania hosted an eInvoicing workshop (Digital) — To prepare for the upcoming Directive 2014/55/EU deadline, the Lithuanian government hosted an eInvoicing workshop
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CEF eTranslation Presented at Translating Europe Forum 2018 (Digital) — CEF eTranslation aims to help European and national public administrations exchange information across language barriers in the EU.
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CEF eDelivery and eInvoicing workshop at the Danish Business Authority (Digital) — What does digital invoicing and infrastructure of the future look like?
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CEF Context Broker Presented at the European Week of Regions and Cities (Digital) — EWRC is an annual four-day event during which cities and regions showcase their capacity to create growth and jobs
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CEF eSignature Presented at ETSI eSignature and eSeal Validation Workshop (Digital) — The one-day workshop discussed standardisation for eSignature/eSeal Validation services provided by Trust Service Providers, addressing conformity assessment, protocols and validation report.
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eDelivery Extended Expert Group Workshop (Digital) — Members of the Extended Expert Group concluded that the CEF eDelivery building block is a key enabler of the EU's Digital Single Market.
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Information session on the AS4 (Digital) — The European Commission is holding a half day information session on Thursday 26 May for software vendors, system integrators, implementers and training providers interested in AS4
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CEF Telecom call 2 virtual Info Day 2016 (Digital) — The 2016 CEF Telecom call 2 virtual Info Day will take place on Friday 3 June 2016 and will cover four priorities of the 2016 CEF Telecom Calls.
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CEF Telecom Call 2 virtual Info Day, 3 June 2016 (Digital) — Up to EUR 70 million is foreseen from the 2016 CEF Telecom Work Programme for grants managed by INEA