FHIR Bulk Data Access (Flat FHIR)

FHIR Bulk Data Access, often called Flat FHIR, is an HL7 standard that adds an asynchronous $export operation to FHIR for moving population-level data efficiently. Instead of paging through resources one API call at a time, a client kicks off an export at the system, group, or patient level and retrieves the result as newline-delimited JSON (NDJSON) files, authorized via SMART Backend Services. It is how analytics, quality reporting, payer exchange, and machine-learning pipelines get whole populations of data out of a FHIR server.