What is HL7 FHIR and why is it important for NHS interoperability?

FHIR (Fast Healthcare Interoperability Resources) is a modern health data exchange standard combining earlier HL7 standards with RESTful APIs, JSON, and XML. It organises clinical data into discrete Resources (Patient, Observation, MedicationRequest, etc.) accessible via standard HTTP verbs. NHS England mandates FHIR R4 with UK Core profiles as the strategic direction for interoperability, used in GP Connect, the National Record Locator, and NHS App integrations.