The European Interoperability Framework (EIF) is a cornerstone of EU digital governance. It defines how public administrations across member states should work together to deliver seamless cross-border services. The four-layer model is a staple in EPSO exams.
The Four Layers
Layer 1: Legal Interoperability
Ensures that organisations operating under different legal frameworks can work together. This means aligning legislation so that data exchanged across borders has equivalent legal value. Example: eIDAS regulation ensures electronic signatures have legal recognition across all member states.
Layer 2: Organisational Interoperability
Aligns business processes, responsibilities, and expectations. Organisations must agree on how they will collaborate, including service level agreements, change management, and governance structures. Think: who does what, when, and how.
Layer 3: Semantic Interoperability
Ensures that the meaning of exchanged data is preserved. If one country's system sends a "date of birth" field, the receiving system must interpret it the same way. This layer relies on common vocabularies, taxonomies, code lists, and data models. Core vocabularies published by the EU (like ISA² Core Vocabularies) are key instruments here.
Layer 4: Technical Interoperability
Covers the technical infrastructure: APIs, data formats, protocols, and standards that enable systems to connect and exchange data. This includes open standards, open-source building blocks, and service-oriented architectures.
The Underlying Layer: Governance
Cutting across all four layers is the integrated public service governance layer. It ensures there is a coordinating body and decision-making process for interoperability at every level — from legal agreements to API specifications.
Common EPSO Questions
- "Which layer ensures that data has the same meaning across systems?" — Semantic
- "eIDAS regulation primarily supports which layer?" — Legal
- "API standardisation falls under which layer?" — Technical
- Order questions: remember Legal → Organisational → Semantic → Technical (from top to bottom)