Serialization
- FHIR ReST APIs MUST support JSON serialisation and SHOULD also support XML serialisation.
- All FHIR ReST endpoints MUST support JSON formatted requests/responses.
- FHIR ReST endpoints SHOULD also support XML formatted requests/responses.
- The serialisation mime-types supported MUST be declared in the Conformance/CapabilityStatement resource for the endpoint, and the server MUST use the usual FHIR mechanisms to allow clients to request a specific Content Type as per the FHIR spec (servers may choose to reject the use of XML if it is not supported).
- Namespaces outside those defined in the FHIR specification MUST NOT be used.
- The FHIR standard specifies a specific namespace for FHIR XML elements, with a second namespace for XHTML content in narrative sections. Those specifying FHIR APIs MUST not use other namespaces in their APIs.