FHIRconnect: towards a seamless integration of openEHR and FHIR

Healthcare interoperability between openEHR and HL7 FHIR remains challenging due to fundamental differences in data modeling approaches and the lack of standardized transformation mechanisms. This paper presents FHIRconnect, a novel domain-specific language (DSL) and open-source transformation engine that enables standardized, bidirectional data exchange between openEHR and FHIR healthcare standards. Our approach addresses critical interoperability gaps through a triple-layered architecture. This design enables 67.3% mapping reuse across projects through international archetype-based foundations while accommodating local customizations. FHIRconnect successfully mapped 24 international archetypes to 15 FHIR profiles across seven clinical domains. Key contributions include the first comprehensive DSL for openEHR-FHIR transformation with formal specification, an open-source execution engine (openFHIR) with an accessible mapping library covering high-impact clinical archetypes. This work establishes the technical foundation for community-driven mapping standardization, reducing the need for custom ETL solutions while advancing syntactic and semantic interoperability in healthcare IT systems based on open standards.