OOTS in production in the European Union: the state of the system in 2026

The digital transformation of European public administration entered a new phase in 2026. The Once-Only Technical System (OOTS), the technical system supporting the once-only principle in the European Union, is now operational across all 27 Member States and has entered a phase of functional expansion and large-scale adoption.

Created under Regulation (EU) 2018/1724, which established the Single Digital Gateway (SDG), the OOTS enables citizens and businesses to avoid repeatedly submitting the same documents when interacting with public administrations in different countries across the Union. Instead, data is exchanged directly between authorised public authorities, subject to the user’s consent.

In 2026, the European Commission established the connection of all competent national authorities to the system, both as evidence providers and evidence requesters, as a strategic objective. By the beginning of the year, the following had been identified:

• 255 administrative procedures;
• 377 types of evidence;
• 95 public authorities already connected to the system.

These numbers continue to grow as Member States move new services into production.

How the OOTS works

The OOTS operates as an infrastructure for the automatic exchange of evidence between European public administrations. In practice, when a citizen or business carries out a cross-border online procedure — for example, applying to a university in another Member State or setting up a company abroad — the user may authorise the destination authority to obtain the necessary documents directly from the official source in the country of origin.

The request is initiated through the Your Europe portal, which acts as a single access point for European digital procedures. Data exchange takes place through the eDelivery infrastructure, while institutional trust and authentication of participating entities are ensured by the eIDAS framework. This means that:

• The citizen does not need to gather paper certificates or supporting documents;
• The authority receives the information directly from the authentic source;
• The evidence is delivered in a structured, up-to-date and legally reliable format.

What is new in 2026: TDD version 2.0

On 19 February 2026, the European Commission’s Gateway Coordination Group adopted by consensus version 2.0 of the OOTS Technical Design Documents (TDD). This new technical version represents the system’s largest evolution since going live in December 2023.

New supported domains

Version 2.0 extends the system to the following domains:

• Professional qualifications;
• Driving licences;
• Short-term rentals;
• Expanded mapping of evidence types.

In addition, the new architecture introduces:

• Full coverage of the requirements of the implementing regulation;
• New security functionalities;
• Advanced adoption of eDelivery services;
• Greater support for structured and interoperable evidence.

It is important to note that this version is not backwards compatible, requiring technical planning by national administrations.

Domains already covered by the system

Before version 2.0, the OOTS already supported procedures related to:

• Education and academic qualifications;
• Vehicle registration;
• Population registers;
• Company incorporation and registration;
• Pensions and social security.

These areas derive directly from the scope defined in the Single Digital Gateway Regulation and its implementing acts.

Integration with the European Digital Identity Wallet

Another strategic priority for 2026 is the preparation of the integration between the OOTS and the European Digital Identity Wallet, the future European digital wallet foreseen under the eIDAS 2.0 framework.

The objectives of this integration are to:

• Simplify the user experience;
• Reuse technological components already implemented by Member States;
• Reduce integration and operational costs;
• Strengthen digital trust in European public services.

This convergence between digital infrastructures is expected to shape the next generation of cross-border public services in the Union.

OOTS timeline

2018: Approval of Regulation (EU) 2018/1724, creating the Single Digital Gateway and establishing the legal basis for the once-only principle in the European Union.

2023: The OOTS officially goes live in all 27 Member States.

2025: The Europe Goes Once-Only event takes place in Lisbon, bringing together more than 300 specialists and reinforcing Portugal’s national coordination role.
Finland launches one of the first OOTS services in production for higher education funding.

2026: The European Commission publishes version 2.0 of the OOTS TDD.
European objective to connect all competent national authorities to the system and beginning of the technical convergence with the EUDI Wallet.

What to expect next

With the OOTS already operational across the Union, 2026 will be a decisive year for the transition from the implementation phase to the phase of widespread use. The challenge is no longer purely technological but institutional: ensuring that every national public authority provides interoperable, secure and user-centred digital procedures.

The European Union’s vision is clear: to allow citizens and businesses to provide data only once, regardless of the country in which they exercise their rights. The OOTS is the infrastructure that makes this vision possible.