Fast Healthcare Interoperability Resources (FHIR) is a standard for health care data exchange, published by HL7®.
FHIR is an interoperability standard intended to facilitate the exchange of healthcare information between organizations. It consists of 2 main parts – a content model in the form of ‘resources’, and a specification for the exchange of these resources in the form of real-time RESTful interfaces as well as messaging and Documents.
It's published by HL7 (Health Level Seven International).
Documentation is available on HL7 website: http://hl7.org/fhir/documentation.html