For decades, the European Union has proudly dismantled physical borders. Today, we cross the continent without showing passports, study abroad as seamlessly as at home, and exercise social and labour rights without feeling we are in “another country”. Integration has become both visible and celebrated. Yet paradoxically, digital borders remain standing — silent, invisible, and often higher than ever.
An Erasmus student still resubmits the same documents to multiple institutions. A company entering new markets repeats bureaucratic processes already completed elsewhere. A citizen seeking medical care abroad discovers their health records do not travel with them. The irony cuts deep: a Europe without physical borders but riddled with digital walls.
The Once Only Technical System (OOTS) was designed to bridge this gap. Envisioned under the Single Digital Gateway Regulation, OOTS should enable citizens and businesses to provide information once to any public administration, with that data then accessible across all member states. In theory, it means the end of redundant paperwork: a diploma submitted in Lisbon should be valid in Berlin; tax residence proven in Paris should not require repetition in Rome.
Technical promise, political resistance
Technically, OOTS represents a federated architecture connecting national base registries — civil, tax, academic, and business records. These link through a European interoperability layer. Each country maintains sovereignty over its systems while enabling secure data exchange, always with citizen consent. It is a decentralised network built on shared standards for semantics, security, and trust.
In practice, however, OOTS remains more promise than reality. Legacy systems, incompatible standards, and uneven digital maturity persist across member states. Cross-border flows of personal data raise complex questions about GDPR compliance. Politically, member states resist ceding digital sovereignty, treating national systems as strategic strongholds. And perception matters: interoperability remains invisible. The average citizen does not demand OOTS because they do not know it exists. Only those who have battled bureaucracy can imagine its value.
Some countries nevertheless push forward. Portugal, through its recently established Agency for Public Administration Reform and Digital Transformation (ARTE), hosted a European summit on the Once Only Principle. This was more than a technical seminar — it was a political statement that even smaller member states can lead by example, demonstrating that digital reform need not be the privilege of the largest or wealthiest.
A metaphor from the business world proves instructive. Companies are often criticised for being “a house of brands” — a dispersed collection of labels — when they should be “a branded house”, leveraging unified identity and shared strength. Europe’s digital future faces the same choice. Do we want to remain “countries with a brand”, where each member state stays locked in its silo? Or should we aspire to become a true “brand of countries”, united under a digital identity that functions seamlessly across borders?
The cost of fragmentation
The answer seems obvious, yet implementation proves elusive. In healthcare, cross-border interoperability of medical records remains a distant goal. In education and labour mobility, digital certificates stay trapped in PDFs and redundant stamps. For small and medium enterprises, European expansion still brings unnecessary administrative costs. Above all, the story remains untold. Citizens experience this not as technology but as time lost or saved in their daily lives.
A Europe without digital borders could already exist. Perhaps it should have emerged long ago. But it is not too late. The technology exists. Artificial intelligence is advancing rapidly. Base registries are maturing. The real challenge is political and cultural: understanding that a digitally united Europe will always be stronger than the most advanced member state standing alone.
Europe risks becoming small through fragmentation. Yet even small countries, as Portugal demonstrates, can achieve more when guided by vision. As Portuguese writer Fernando Pessoa once observed, “A man is not the size of his height, but the size of what he sees.” Europe too must be measured not by the number of its member states or the weight of its institutions, but by the vision it chooses to embrace. Physical borders are gone. The time has come to abolish the digital ones.
Carlos H. Jerónimo is Assistant Professor and Researcher at ISCTE Business School in Lisbon.
