Health informatics is characterized by the need to securely store, process and transmit large amounts of sensitive medical data while ensuring interoperability with other systems. Among many standards used in such systems there are two which have gained interest in recent years and cover most of those needs: openEHR and HL7 FHIR. In this paper, both standards are discussed and compared with each other. The architecture of both systems, the similarities and differences, methods of data modeling and ensuring interoperability were presented.