Nordic Baltic OOTS 2.0 Project
The Once-Only Technical System (OOTS), mandated by the Single Digital Gateway (SDG) Regulation, enables the cross-border exchange of evidence between public authorities in EU Member States. The Nordic-Baltic OOTS 2.0 project was launched in 2024 to explore how OOTS could evolve beyond its initial implementation by enabling smarter use of structured data, improving user experience and supporting seamless digital public services across borders.
The project is funded by the Nordic Council of Ministers for Digitalisation and brings together the national SDG coordination teams and experts from Finland, Estonia, Latvia, Lithuania, Sweden and Denmark, Norway and Iceland. The project is led by the Finnish KEHA Centre.
From Studies to Practical Testing
During 2024 and 2025, the project completed service design, as well as legal and technical studies. These activities provided the foundation for a series of practical Proof-of-Concept (PoC) implementations designed to test how OOTS could support future cross-border digital services.
The studies helped identify opportunities and challenges related to structured data exchange, user experience, transparency and future interoperability. The subsequent Proof-of-Concept activities were designed to validate these findings in practice and assess how they could be applied in real cross-border digital services.
The Proof-of-Concept activities focused on three main questions: how OOTS could support the exchange and reuse of structured data, how the user experience could be improved, and how OOTS-related capabilities could be reused in procedure portals and emerging European Wallet services.
Key Results
Cross-border exchange of Proof of Enrolment data
One of the project's first use cases focused on exchanging structured educational evidence data, namely Proof of Enrolment. The project successfully tested cross-border exchange of educational evidence with Estonia and Lithuania using the OOTS infrastructure.
Structured data in application forms
The project demonstrated how structured educational evidence data received through OOTS can be integrated directly into multilingual application forms. Instead of treating evidence as a document attachment, information can be used to pre-fill forms and support automated processing, reducing manual data entry and improving the user experience. The Proof-of-Concept activities indicate that OOTS could support not only the exchange of evidence, but also wider use of structured data in cross-border digital procedures.
Improving the user experience
The project explored ways to better integrate OOTS into national procedure portals, reducing the need for users to switch between different systems during a procedure. Single Sign-On (SSO) approaches were also examined to simplify authentication and reduce the number of login steps required in cross-border services where possible.
OOTS and the European Digital Identity Wallet
A dedicated Wallet Proof-of-Concept explored how OOTS-related structured evidence could be issued and reused through the European Digital Identity Wallet (EUDI Wallet). The results showed that existing OOTS investments, such as integrations, evidence definitions and data models, could support future wallet-based public-sector credentials and create synergies between these European initiatives. Together, the project's Proof-of-Concept activities indicate that OOTS could support not only structured evidence exchange, but also wider reuse of structured data and future interoperability with the European Wallet ecosystem.
My OOTS Data
The final Proof-of-Concept area under development is My OOTS Data, a concept designed to improve transparency and trust. The objective is to provide users with an overview of what evidence has been shared, from which source and with which authority. This final PoC phase is expected to be finalised in the 2026.
Looking Ahead
The project is in its final phase, with most planned Proof-of-Concept activities already completed. The project has validated key concepts related to structured data exchange, user-centric service design, transparency, and wallet interoperability. Final evaluation, stakeholder review and project reporting will be completed during 2026 and provide recommendations for future OOTS development and next-generation cross-border digital public services.
As the project concludes, the findings will be communicated at different levels to support future policy discussions and practical implementation of cross-border digital services.
For further information about the project, please contact:
Project manager
Kirsi Mikkonen
Employment, Development and Administration Centre, KEHA Centre, Finland