The proposal for a European regulation on public procurement: the once-only principle and the new European system for verifying eligibility requirements

The once-only principle in public procurement: from legal recognition to effective interoperability

One of the principles now firmly established in the digitalisation process of European public administration is the so-called once-only principle (OOP), under which citizens and businesses should not be required to provide public authorities more than once with data and documents already held by a public authority. The European Commission expressly links the principle to reducing the administrative burdens associated with the digitalisation of public procurement.

In the field of public procurement, the principle is already recognised in Directive 2014/24/EU.

Article 59 provides that economic operators are not required to submit supporting documents where the contracting authority can obtain the relevant information directly by accessing, free of charge, a national database available in any Member State. The same provision also requires Member States to make databases that may be consulted by their own authorities accessible, under the same conditions, to contracting authorities in other Member States. (1)

The proposal for Regulation COM(2026) 590 final, presented by the Commission on 9 September 2026 and entitled Public Procurement Act, nevertheless starts from the finding that this legal recognition has not resulted in full integration of verification systems: the current digital procurement ecosystem is described as «fragmented, non-interoperable and insufficiently data driven».

Fragmentation is particularly significant in cross-border participation. Despite a common EU framework on exclusion grounds and selection criteria, the gathering and verification of the relevant evidence continue to depend on the administrative and digital infrastructures of individual Member States.

For economic operators with a more limited presence in international markets, this may translate into greater administrative burdens and difficulties in identifying how to prove compliance with the requirements. The Commission in fact links the use of interoperable digital tools and structured data both to reducing repetitive formalities and to facilitating cross-border participation.

The issue is not new. At European level, the TOOP project, launched in 2017, tested the cross-border exchange of business data based on the once-only principle, with the aim of ensuring that information would be provided to administrations only once, irrespective of the economic operator’s country of origin. In Italy, the digitalisation process in public procurement has led to the Virtual Economic Operator File (FVOE), used to access the information needed to verify participation requirements.

The central issue, therefore, is not the recognition of the principle, which is already part of the current framework, but its effective operation across national borders. It is this limitation that the proposed regulation seeks to address.

From rule to infrastructure: European centralisation of access and verification

The step change pursued by the proposal lies in building a common infrastructure capable of making the once-only principle operational in practice on a European scale.

The Commission outlines a digital ecosystem based on an interoperability network, harmonised semantic standards and common digital services, in which the verification of eligibility requirements is one of the main areas of integration. (2)

The model does not provide for the centralisation of information in a single European database. Rather, centralisation concerns the access and verification layer: Article 133 provides that the Commission is to set up and operate an electronic eligibility service, intended to verify exclusion grounds, selection criteria and requirements of origin for each procurement procedure. (3)

Economic operators will have to create their own eligibility profile in the system, through which the public buyer will be able to verify compliance with the requirements by means of digital credential tools. (4)

However, the information sources remain distributed across the Member States. Accordingly, the proposal provides that, by 15 June 2029, they are to make the relevant national databases accessible to the system free of charge, including those concerning criminal convictions, tax and social security obligations, insolvency proceedings and selection criteria. (5)

The European system therefore operates as a common access layer for information that continues to be held and updated at national level.

The reform does not stop at data acquisition. Where the electronic eligibility service makes available an automated verification of the existence of an exclusion ground or compliance with a selection criterion, the public buyer must use that verification for its decision on eligibility. (6)

The decision therefore remains attributable to the contracting authority, while part of the fact-finding activity that precedes it is entrusted to a common interoperable infrastructure.
The change is primarily organisational: the proposal does not replace national sources, but seeks to eliminate the need for each authority to know and independently query the methods of proof specific to the economic operator’s Member State of establishment. The European once-only rule is thus accompanied by a European layer for accessing and verifying evidence.

Implementation timelines and the question of the effectiveness of national systems

However, the effectiveness of the new model will depend on the ability of national systems to feed the European infrastructure correctly. The electronic eligibility service constitutes the common access and verification layer, but cannot by itself remedy the absence, incompleteness or lack of interoperability of the underlying information.

Italy’s experience illustrates the problem in concrete terms. The FVOE does not yet allow all the evidence needed to verify the requirements to be obtained exhaustively: ANAC expressly notes that not all documents relating to general and special requirements are available in the file. (7)
In some cases, the limitation does not even result from a malfunction of the FVOE, but from the absence of a centralised database at the certifying body or from the failure to make an existing database available. (8)
In such cases, the digital source that the infrastructure should access is itself missing.

The same problem may recur on a larger scale in the European model. A common access point simplifies verification only to the extent that the underlying information is actually available in structured and interoperable form. The proposal addresses the possibility that particular evidence may not be available through the system: in that case, the economic operator relies on self-declaration and the public buyer may subsequently request the necessary documentation. (9)

This solution prevents an incomplete infrastructure from blocking the procedure, but makes the model’s substantive limitation clear: the greater the reliance on residual methods of providing evidence, the less fully the once-only principle will be realised.

The proposal therefore provides for gradual implementation. For digital credential tools defined at Union level, Article 133 requires technical implementation in all Member States and general availability to economic operators by 30 June 2028. (10)

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