In many cross-border employment structures, the A1 certificate has quietly become a symbol of reassurance. Once the document is in the file, a sense of order settles in. Social security has been addressed, the worker remains insured in another EU member state and the administrative side appears under control. For many organizations, that moment marks the point where compliance concerns fade into the background. The A1 certificate sits in the documentation and the project moves forward.
But the A1 certificate answers only one question and it answers it very precisely. It determines which country’s social security legislation applies to a worker who is temporarily active in another member state. It clarifies where contributions are paid and which system remains responsible during the posting.
What it does not determine is whether the overall employment structure reflects reality.
That distinction is becoming increasingly relevant as authorities across Europe pay closer attention to cross-border labour arrangements. In Netherlands in particular, inspectors are looking beyond the existence of documents and focusing more closely on the factual relationship between the worker, the foreign employer and the Dutch client.
When an inspection takes place, the conversation rarely revolves around the A1 certificate itself. The document may be present, valid and correctly issued. Yet the discussion quickly moves in another direction. Inspectors want to understand how the arrangement actually works in practice. They look at who recruited the worker, who directs the work on a daily basis and who ultimately benefits from the labour performed in Netherlands.
In other words, they look for substance.
This becomes particularly relevant when a worker is formally employed by a company in one EU member state but performs activities almost entirely within the operational structure of a Dutch end client. Over time the practical reality may begin to drift away from the legal framework that was originally designed. The foreign employer may remain the contractual employer on paper, yet the center of control may slowly shift to the Dutch organization where the work takes place.
From an administrative perspective nothing appears unusual. Salaries are paid by the foreign employer, social security remains registered abroad and the A1 certificate continues to confirm that arrangement. On the surface, the structure seems stable.
But inspectors are increasingly interested in a different question: whether there is still a genuine and active relationship between the worker and the foreign employer.
Connections
European social security coordination rules require a real connection between the posted worker and the sending employer. The posting is meant to remain temporary and the employer in the sending state is expected to maintain an actual role in the employment relationship. When that connection becomes largely formal while the daily reality unfolds elsewhere, authorities may start to question whether the original framework still reflects the facts.
This does not mean that cross-border posting itself is problematic. On the contrary, labour mobility is an essential part of the European internal market and the A1 certificate plays an important role in facilitating that mobility. Companies regularly deploy specialized staff across borders to deliver projects, transfer knowledge and support international operations. In many cases these arrangements function exactly as intended.
The difficulty arises when the practical organization of work gradually evolves into something different from the structure that was originally documented. A project that was meant to be temporary extends year after year. The worker becomes integrated into the Dutch client’s team. Decisions about tasks and priorities are taken locally. The foreign employer remains involved primarily through payroll administration.
At that point the question is no longer whether the A1 certificate exists. The question is whether the employment relationship still aligns with the conditions under which the certificate was issued.
This is precisely why authorities are paying increasing attention to the so-called organic link between the worker and the sending employer. They are trying to determine whether the foreign employer genuinely directs the employment relationship or whether the arrangement has effectively turned into a labour supply structure operating under a different label.
Compliance in cross-border environments
For organizations operating in cross-border environments, this shift in attention is important to understand. Compliance cannot be reduced to collecting the right documents. Documentation remains necessary, but it only reflects the structure as it was designed at a particular moment in time. Over the course of a project, operational realities may evolve in ways that were never fully anticipated.
When inspectors review a cross-border structure, they do not only examine the paperwork that was prepared at the start. They examine the situation as it exists today. They want to understand how the work is organized, who directs the worker and how the employment relationship functions in practice.
The whole story
The A1 certificate remains a valuable instrument within the European system. It creates clarity about social security obligations and prevents workers from being subject to multiple systems simultaneously. But it was never intended to serve as a comprehensive compliance shield.
It answers an important question, but not the only one that matters. And in the current enforcement climate, authorities are increasingly focused on the questions that lie beyond it.