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The Once-Only Technical System and eDelivery: putting evidence sharing at the heart of EU-wide interoperability

13 October | 6 minutes read

The building blocks of digital interoperability in Europe

Today, most large EU Trans-European Systems (e.g., eJustice, eProcurement and Customs) reuse well-established building blocks such as eDelivery, eID, and eSignature. These building blocks represent an investment of over EUR 126 million by the Connecting Europe Facility (CEF), ISA2, and the Digital Europe Programme (DIGITAL).

A building block is an open and reusable digital solution. It can take the shape of a framework, a standard, a piece of software or software-as –a-service (SaaS), or any combination of these. Reuse of existing digital tools not only prevents the reinvention of the wheel but also, and more importantly, helps to save time and reduce costs while increasing interoperability among the Member States participating in the Single Market.

The Once-Only Technical System and eDelivery

Following their successful adoption by all Member States, some building blocks were included in the Commission’s Implementing Regulation, setting out the technical and operational specifications of the Once-Only Technical System (OOTS). Thanks to the Once-Only Technical System, websites, and authentic sources of information from public authorities from all Member States will be able to automatically discover and exchange data at citizens’ and businesses’ request.

The Once-Only Technical System will be a secure technical system for the automated cross-border exchange of documents (legally referred to as “evidence”) between those organisations involved. The OOTS serves primarily as an integration mechanism for existing systems in the Member States. The Member States and the Commission are committed to using pre-existing technologies to realise the Once-Only Technical System’s architecture. This reduces both costs and development time.

The Once-Only Technical System allows various governmental portals to request (at the explicit request of the user) the sharingof evidence from one or several competent authorities between different EU Member States. It aims at enabling cross-border data-sharing between competent authorities at all administrative levels (local, regional, and national).

Along with technologies from other building blocks, such as eID, and the EUDI Wallet Initiative, the Once-Only Technical System will reuse eDelivery access points to create a virtual secure network. eDelivery helps governments – as well as businesses and citizens – to exchange data and documents in a reliable and trusted way. Each Member State will establish one or more eDelivery nodes through which the evidence sharing will take place. The use of eDelivery in the Once-Only Technical System will lay the foundation for cross-domain and cross-sector interoperability across the EU. Evidence available through Once-Only Technical System can be made available to other eDelivery-based domains without technical barriers, promoting a “once-only” by design approach.

Architectural design of the Once-Only Technical System

Architectural design of the Once-Only Technical System

eIDAS nodes allow authentication to any online procedure portal in Europe using a national eID, while the eDelivery access points enable easy requests for sharing evidence between the authorities. The cross-border application of the ‘once-only’ principle means that citizens and businesses do not have to supply the same data to public authorities more than once.

In addition to eDelivery and eID, the European Commission provides the following common services as part of the Once-Only Technical Architecture:

  • The Data Service Directory is a common service that acts as a catalogue of evidence types that can be provided upon request.
  • The Evidence Broker is an authoritative system that maps specific data sets as evidence types that prove specific requirements.
  • The Semantic Repository is a common service that acts as a data portal for the technical system.

Want to learn more about eDelivery and OOTS?

The Commission organises regular events looking at the immense value of digital building blocks such as eDelivery and the Once-Only Technical System.

Register now for the following events:

  • Webinar: “New features in Domibus 5.0” - 18 October 2022, 14:00 - 15:30 (CET (Central European Time). During this event, the eDelivery team will guide you through the changes and additions to the latest version of Domibus, the sample implementation of eDelivery Access Point maintained by the Commission.
  • Webinar: “Domibus Plugins” - 22 November 2022, 14:00 - 15:30 (CET). During this event, users will learn how to use the three standard Domibus plugins for sending and receiving messages (web service plugin, JMS plugin, and file system plugin).

Want to know more about upcoming eDelivery events? Visit the dedicated webpage or send an email to EC-DIGITAL-BUILDING-BLOCKS@ec.europa.eu.

If you want to learn more about the Once-Only Technical System, you can visit this website.