2. Validation, Conformance & Compliance Testing

Ensuring the quality, interoperability and trustworthiness of digital public services requires a clear distinction between validation, conformance and compliance, as each of these activities serves a different purpose in the engineering and governance of interoperable solutions.

This section defines these concepts, describes their relationship with the European Interoperability Reference Architecture, and establishes the mechanisms, levels and profiles through which solutions can be assessed.

2.1. Distinguishing Validation, Conformance and Compliance Testing

The quality and trustworthiness of interoperable digital public services depend on three complementary assurance mechanisms: validation, conformance, and compliance. Although related, each addresses a different dimension of correctness and must therefore be assessed independently. This section clarifies their purpose and scope within the European Interoperability Reference Architectures.

2.1.1. Validation

Validation determines whether the architecture and its design correctly reflect the functional, non-functional and interoperability requirements identified during the analysis phase. It assesses the fitness-for-purpose of the solution and its ability to fulfil policy objectives, user needs and domain-specific constraints.

Validation focuses on:

  • Alignment with functional, non-functional and interoperability requirements.

  • Correct interpretation of legal and policy objectives.

  • Coherence across the LOST interoperability views.

  • Appropriateness and justification of architectural assumptions and constraints.

  • Correct derivation of design artefacts from EIRA-based requirement analysis.

Validation includes verification against the architecture principles of ELAP, ensuring that interoperability principles guide the transformation from requirements (EIRA) to design (eGovERA).

2.1.2. Conformance

Conformance verifies whether the architecture correctly applies the European Interoperability Reference Architectures, including the use of prescribed building blocks, principles, modelling rules and design patterns. It ensures that the solution is consistent with the interoperability-by-design approach defined by EIRA and eGovERA.

Conformance assesses:

  • Correct instantiation and reuse of ABBs and SBBs.

  • Adherence to EIF, EIRA and eGovERA architecture principles.

  • Proper structuring of the architecture using LOST interoperability views.

  • Traceability between requirements (analysis) and solution components (design).

  • Compliance with ArchiMate modelling rules and well-formedness constraints.

  • Appropriate integration of reusable interoperability solutions and EU-level enablers.

Conformance is an architecture-driven verification activity and may involve automated model checking, use of the Interoperability Test Bed, and expert architectural review.

2.1.3. Compliance

Compliance assesses whether the solution conforms to binding EU and national legislation, sectoral regulatory frameworks and policy-driven requirements. It ensures that the solution can be lawfully deployed and operated within the European administrative and legal ecosystem.

Compliance checks include:

  • Fulfilment of the binding interoperability requirements of the Interoperable Europe Act.

  • Alignment with the GDPR and data protection principles.

  • Requirements derived from the Data Governance Act, the Data Act and the Open Data Directive.

  • Relevant sector-specific legislation (e.g. health, taxation, customs).

  • Security, accessibility, procurement and digital inclusion requirements.

Compliance is a law- and policy-driven activity, and provides legal assurance that the solution operates within the applicable regulatory framework.

2.2. Conformance Levels

Conformance levels define the extent to which a digital public service solution must adhere to the European Interoperability Reference Architectures. They enable proportional, transparent and repeatable assessment across different contexts while ensuring that interoperability-by-design is consistently applied.

Three conformance levels are established:

2.2.1. Mandatory Conformance

Mandatory elements must be satisfied for any solution claiming alignment with the reference architectures. These requirements ensure baseline interoperability, legal validity and architectural correctness.

Mandatory conformance includes:

  • Application of the ELAP architecture principles.

  • Use of the LOST interoperability views (Legal, Organisational, Semantic, Technical).

  • Use of ArchiMate as the architecture ontology.

  • Use of relevant mandatory ABBs/SBBs.

  • Passing the ITB-based conformance validation for mandatory well-formedness rules.

2.2.3. Optional Conformance

Optional elements may be applied to improve performance, usability or domain specificity depending on contextual needs.

Optional conformance may include:

  • Domain-specific modelling extensions.

  • Optional architectural accelerators or cross-domain enablers.

  • Additional SBBs not required for general interoperability.

Optional elements never compromise the mandatory principles or the structural integrity of LOST-aligned models.

2.3. Compliance Profiles

Compliance profiles specify how the reference architectures should be interpreted and applied across different operational contexts. They enable proportionality and support both horizontal and sector-specific digital transformation strategies.

Three main profiles are defined.

2.3.1. Cross-Border Compliance Profile

This profile applies to solutions operating across borders or involving joint implementation by Member States and EU institutions.

It places emphasis on:

  • Cross-border legal interoperability and recognition.

  • High-level semantic harmonisation (datasets, vocabularies, ontologies).

  • Consistent use of EU-level building blocks and shared enablers.

  • Mandatory conformance to ELAP principles and LOST views.

  • Mandatory passing of the ITB conformance validator for cross-border scenarios.

2.3.2. Sector-Specific Compliance Profile

This profile applies to digital public services in specialised policy domains such as health, justice, mobility, taxation, customs or social security.

It requires:

  • Incorporation of domain-specific legislation and regulatory obligations.

  • Use or alignment with sectoral semantic models, datasets and standards.

  • Domain-specific ABBs and SBBs derived from EIRA/eGovERA but enriched with domain constraints.

  • Additional compliance checks related to safety, criticality or domain assurance.

2.3.3. Organisational Compliance Profile

This profile applies to solutions implemented within a single public administration or organisational cluster. It focuses on:

  • Alignment with internal strategies, governance structures and digital capabilities.

  • Adoption of reusable building blocks at organisational level.

  • Tailored modelling choices that remain compatible with ELAP and LOST views.

Gradual adoption of mandatory conformance elements according to organisational maturity.