The Once-Only hub.Unlocking the full potential of the Single Market.
Welcome to the Once-Only Hub, a single environment providing reliable information and services relating to the Once-Only Technical System.
The Once-Only Technical System lets EU public authorities securely exchange official documents and data at the request of citizens and businesses as part of cross-border administrative procedures, e.g., when registering an address or vehicle when moving abroad. This innovative system eliminates the complicated manual search, mapping, and fetching of data between Member State authorities, improving efficiency, making people's lives easier, and reducing the costs of mobility in the Single Market.
Video
Watch this video to learn more about Once-Only.
Introduction to the Once-Only Technical System (OOTS)
The Once-Only Technical System is a technical framework for data sharing. As of the end of 2023, citizens and businesses will be able to request official documents (known as “evidence”) to complete administrative procedures allowing people to study, work, live and retire in other EU countries in 7 simple steps. The decentralised architecture connects public authorities, so they can exchange evidence at the citizen's or business' request.
Discover the 21 procedures covered by the SDG Regulation in the scope of Once-Only Technical System and how EU citizens and businesses can benefit from Once-Only Technical System.
Once-Only Technical System - user journey for cross-border procedures
The user-journey refers to the steps anyone, a citizen or business, must take when using the Once-Only Technical System with a mind to the overall experience the user has.
Once-Only Technical System architecture
The Once-Only Technical System architecture adopts a decentralised approach, integrating and connecting systems through an interoperability layer using reusable "Building Blocks".
OOTS Guidance Presentation
The Guidance Presentation provides a useful introduction for teams across the EU working on the implementation of the Once-Only Technical System.
Once-Only Technical System Projectathons
Since 2023, the Commission has been organising Once-Only Technical System Projectathons. These are three-day events where national teams connect various systems and perform a marathon of peer-to-peer interoperability and compliance tests in a structured environment.
Discover more details about Projectathons and explore the steps you need to take to actively participate in the upcoming Projectathons.
Common and supporting services
To provide comprehensive support and proper exchange of evidence between Data Services and Online Procedure Portals, the Once-Only Technical System uses Once-Only common services and additional supporting services.
Technical design documentation
The technical and operational specifications of the Once-Only Technical System, are complemented by detailed, non-binding technical design documents jointly prepared by the Commission and Member States.
Latest news
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Commission publishes Once-Only Common Services 1.4.0 (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/770146348/illu-news-oots-22-07-2024.png
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Italy becomes fifth Member State to publish evidence types (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/768802960/illu-news-oots-19-07-2024.jpg
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Webinar on eDelivery: intro, value and success stories. 28 September 2023 (eDelivery User Community) —
28 September 2023 | Past event
Webinar on eDelivery: intro, value and success stories
In this webinar, users will discover the eDelivery service offering and the advantages of adopting eDelivery...
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Member States discuss status of Once-Only in June 2024 SDG Gateway Coordination Group (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/757990079/illu-news-oots-27-06-2024.png
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Contact Group publishes report on synergies between the Once-Only Technical System and EU Digital Identity Wallet (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/713526462/illu-news-oots-eudi-wallet-synergies.jpg
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Access the Once-Only Evidence Explorer to make use of the Once-Only Technical System (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/716146821/illu-news-oots-12-03-2024.jpg
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Commission publishes Once-Only Technical System Onboarding Playbook (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/716146400/illu-news-oots-08-03-2024.jpg
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OOTS-EMREX “bridge” will increase student mobility in the EU (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/713528198/illu-news-oots-28-02-2024.jpg
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Enrico Letta calls for Single Market to go ‘Once-Only’ (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/734265446/illu-news-oots-22-04-2024.jpg
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Commission and EU Member States formally kick off May 2024 OOTS Projectathon (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/720503948/illu-news-oots-17-04-2024.jpg
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Commission launches Once-Only Technical System Onboarding Toolkit (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/716151394/illu-news-oots-27-03-2024.jpg
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Member States advance Once-Only implementations in two-day testing event (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/716150475/illu-news-oots-22-03-2024.jpg
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Once-Only on show at Interoperable Europe Academy 2024 (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/720503070/illu-news-oots-15-04-2024.jpg
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A more user-centric public sector in the EU Single Market: Links between the Single Digital Gateway and interoperability of public administrations (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/745996305/illu-news-oots-06-06-2024.jpg
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Member States meet for third progress Accelerator event driving forward #OnceOnly (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/750977088/illu-news-oots-14-06-2024.jpg
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Commission publishes event report for May 2024 Once-Only Technical System Projectathon (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/748355586/illu-news-oots-10-06-2024.jpg
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EU Member States take stock of Europe’s Once-Only journey after #10 OOTS Implementers Café (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/746717191/illu-news-oots-07-06-2024.jpg
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‘Once-Only’ Presented at the Hannover Messe 2024 (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/739901478/illu-news-oots-27-05-2024.jpg
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The #4 OOTS Projectathon welcomes brand new stakeholders to help complete the Once-Only Technical System (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/734920989/illu-news-oots-17-05-2024.jpg
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OpenPeppol's eInvoicing & eProcurement Conference on 30 May 2024 (eDelivery User Community) —
30 May 2024
OpenPeppol's eInvoicing & eProcurement Conference
The conference's second day features a session titled "Critical infrastructure considerations and the future of eDelivery", presented by the eDelivery project officer Bogdan Dumitriu. This OpenPeppol event takes places in Brussels.
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eDelivery Interoperability Event. 11 & 25 June and 1 October 2024 (eDelivery User Community) —
11 & 25 June, 1 October 2024 | 14-17 CEST
Interoperability Event for testing the eDelivery AS4 specifications
The collaboration between eDelivery and software providers continues with the Interoperability Event, in which we test the updated eDelivery AS4 2.0 draft specifications. After the summer break, we will resume testing on 1 October.
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10th eDelivery Informal Cooperation Network Meeting. 15 May 2024 (eDelivery User Community) —
15 May 2024 | Full day
10th eDelivery Informal Cooperation Network Meeting
This time will be in a fully remote format. The ICN is a platform for Member State 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.
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11th eDelivery Informal Cooperation Network Meeting. 26 November 2024 (eDelivery User Community) —
26 November 2024 | Full day
11th eDelivery Informal Cooperation Network Meeting
The eDelivery ICN is a platform for Member State representatives who are involved in the set-up of national eDelivery infrastructure to actively contribute to the adoption of eDelivery at national and EU levels.
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Webinar on eDelivery value proposition: national experiences. 16 January 2025 (eDelivery User Community) —
16 January 2025 | 14:00-16:00
Webinar on eDelivery value proposition: national experiences
We invite you to discover the eDelivery service offering and the advantages of adopting eDelivery. Stakeholders will have the opportunity to discover the success stories and live testimonials from some of the Member States that adopted eDelivery.
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Webinar on eDelivery Trust Models. 2025 March tbc (eDelivery User Community) —
2025 March tbc
Webinar on Trust Models used in eDelivery
We will present Trust Models used in eDelivery. This will be for both those who are interested in using eDelivery and those who would like to better understand Trust Models to assess how these suit their purpose in a particular scenario.
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Webinar on using dynamic discovery. 26 September 2024 (eDelivery User Community) —
26 September 2024
Webinar on using Dynamic Discovery
We will present Dynamic Discovery in an eDelivery network based on our SMP profile, specification for publishing service metadata within a 4-corner network, and our BDXL profile, specification for locating service metadata within such a network.
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eDelivery Interoperability Forum. 24 October 2024 (eDelivery User Community) —
24 October 2024 | 10:30-12:30
eDelivery Interoperability Forum
The collaboration between eDelivery and software and service providers continues in 2024...
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DomiSMP 5.0 video guides. Released on 19 March 2024 (eDelivery User Community) —
19 March 2024
How-to video on DomiSMP 5.0 new features
This video will guide you through the use and possibilities of DomiSMP, the sample software provided by the European Commission to implement an eDelivery Service Metadata Publisher for publishing and retrieving data.
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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 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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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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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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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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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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Information session on AS4 (Digital) — The Information Session was primarily aimed at software vendors, system integrators, implementers and training providers interested in AS4
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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
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CEF Digital 2018 at the Trust Services Forum 2016 (Digital) — Today the European Commission Directorate General for Informatics (DIGIT) presented a state-of-play of the CEF building blocks to the ENISA Trust Services Forum 2016.
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CEF Digital 2018 Presented at the Agency for Administrative Modernisation (Digital) — The event consisted of representatives from both the public and private sectors, including municipalities, government ministries, as well as consulting and IT companies
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EESPA General Assembly 2016 (Digital) — CEF Digital 2018 presented eInvoicing at the EESPA general assembly meeting on 19 May in Tallinn, Estonia
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Register now for the fifth annual conference on innovative public procurement (Digital) — The European Commission is organizing a conference focusing on public procurement of innovation and the potential of innovative procurement on 26 October in Berlin.
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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 eDelivery and eInvoicing DSI Stakeholder Days (Digital) — We invite you to be part of the CEF eDelivery & eInvoicing Stakeholder Days, which are to be held on 29 November – 1 December 2016
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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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CEF eID Presented at the FIDO Alliance (Digital) — CEF eID helps public administrations and private online service providers to easily extend the use of their online services to citizens from other EU Member States
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Trust Services Forum 2016 (Digital) — ENISA, in collaboration with the European Commission eIDAS Task Force, is organizing, for the second consecutive year, the Trust Services Forum 2016.
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Update: Information session on AS4 (Digital) — The European Commission is holding a half day information session on Thursday 26 May 2016
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CEF Digital 2018 at CeBIT 2016 in Hannover, Germany (Digital) — CEF Digital 2018 made its second appearance at CeBIT with a booth entitled "Digital Public Service across Borders" positioned in the Public Sector Park hall.
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eDelivery Interoperability Forum. 18 April 2024 (eDelivery User Community) —
18 April 2024 | 10.30 - 12.30
eDelivery Interoperability Forum: AS4-conformant solutions
In the second community meeting this year, we are going to focus on the eDelivery AS4-conformant solutions and their new listing on our website. For this, dear product and service vendors, please share updated information about your software.
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SEMIC 2024: Interoperable Europe - from vision to reality on 27 June 2024 (eDelivery User Community) —
27 June 2024
SEMIC 2024: Interoperable Europe - from vision to reality
eDelivery will be presented together with other Building Blocks. SEMIC takes place in Brussels and is hosted by the European Commission, in partnership with the Belgian Presidency of the Council of the EU and Digital Flanders.
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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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How-to video on Domibus 5.1 and 5.2 new features. Available in Q4 2024 (eDelivery User Community) —
Q4 2024 | time tbc.
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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Boosting the EU Single Market: Towards the Single Digital Gateway 2.0 on 19 March 2024 (eDelivery User Community) —
19 March 2024
Boosting the EU Single Market: Towards the Single Digital Gateway 2.0
eDelivery has been presented together with other Building Blocks in the event "Boosting the EU Single Market: Towards the Single Digital Gateway 2.0" on 19 March 2024 at Concert Noble in Brussels.
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eDelivery Interoperability Forum. 29 February 2024 (eDelivery User Community) —
29 February 2024 | Past event
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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Can verifying legal entities be as easy as 1, 2, Web3? (EBSI) —22 February2024
Can verifying legal entities be as easy as 1, 2, Web3?
9:45 to 13:30 CET | Physical meeting
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EBSI Demo Day (EBSI) —31 May2022
EBSI Demo Day
9 AM to 5 PM CET | Online event
How can EBSI help citizens study, find a job, and start new lives abroad?
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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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Reusable Components at DIGITEC 2016: Digital Future (Digital) — The IT Departments of the European Commission (DIGIT) and the European Parliament (ITEC) have joined forces to organise DIGITEC 2016: Digital Future.
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9th eDelivery Informal Cooperation Network Meeting. 9 November 2023 (eDelivery User Community) —
9 November 2023 | Past event
eDelivery Informal Cooperation Network Meeting
In this meeting, the representatives of Member States are discussing and sharing the eDelivery implementation in the Member States...
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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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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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eDelivery presented at ENTSOG's Third Workshop on Data Exchange and Cybersecurity in the Energy Sector 17-18 October 2023 (eDelivery User Community) —
17-18 October 2023 | Past event
eDelivery at ENTSOG's Third Workshop on Data Exchange and Cybersecurity in the Energy Sector
In this Third Workshop on Data Exchange and Cybersecurity in the Energy Sector, organised by ENTSOG, Bogdan Dumitriu is presenting rationale for eDelivery AS4 profile updates. His presentation will cover the reasons why there is a need for a new AS4 profile, the highlights of the planned changes and more..
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Webinar on dynamic discovery. 8 June 2023 (eDelivery User Community) —
08 June 2023 | Past event
Webinar on dynamic discovery
The webinar will present the use of dynamic discovery in an eDelivery network based on the eDelivery SMP profile, an open technical specification for publishing service metadata...
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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 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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EU Member States note success of first Once-Only Technical System Projectathon (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/668536918/illu-news-oots-21-04-2023.jpg
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OOTS Implementers take stock of Once-Only ‘Preview Space’ and successful April 2023 Projectathon (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/668547463/illu-news-oots-11-05-2023.png
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Commission publishes April 2023 Once-Only Projectathon ‘aftermovie’ (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/674502000/illu-news-oots-07-06-2023.png
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Commission publishes event report for April 2023 Once-Only Technical System Projectathon (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/668553728/illu-news-oots-22-05-2023.png
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EU Member States celebrate the Go-Live of the Once-Only Technical System (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/704839884/illu-news-oots-12-12-2023.png
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Council of the EU Working Party on Competitiveness and Growth welcomes progress on Europe’s Single Digital Gateway (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/713526449/illu-news-oots-21-02-2024.jpg
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Formal Publication of Once-Only Technical System Technical Design Documents - Q4 2023 release (OOTSHUB) —https://ec.europa.eu/digital-building-blocks/sites/download/attachments/708412032/illu-news-oots-09-01-2024.jpg
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SDG Once-Only Collaborative Space
In the context of the Once-Only Technical System, the mission of this group is to coordinate the implementation work around the setup of the Once-Only Technical System. The members of this group are the Member States (and other public entities). This groups is only accessible by representatives of the Member States (and other public entities).
Sub-groups
Six sub-groups have been set-up to examine specific topics related to the Once-Only Technical System and are expected to report to the Single Digital Gateway Coordination Group. They enable the participation of all Member States in the discussion and ensure the work done by Member State experts is monitored. The sub-groups can only be joined by experts officially nominated by their National Coordinators.
OOTS Projectathon collaborative space
The objective of this space is to encourage dialogue and exchange of ideas between stakeholders in an open and transparent environment. It will mainly serve to promote the Implementers Café series in preparation of the Projectathons. Space users should be implementers of the Once-Only Technical System.
Service desk
The Service Desk helps users improve the performance, continuity and reliability of their Once-Only Technical System implementations.
Once-Only Technical System in use
Projectathons
Number of Member States participating in OOTS Projectathons.
Common Services
Number of Member States connected to Commission-provided Common Services.
Testing Services
Number of Member States connected to Testing Services.