NHS England FHIR Implementation Guide (deprecated)

Important Announcement regarding this Implementation Guide

As of 04/10/2023, this implementation guide has been deprecated and all development on the legacy NHS England FHIR Implementation Guide assets has ceased.
Therefore, vendors looking to start new implementations or looking to update existing implementations should use the new NHS England Implementation Guide. Vendors continuing to implement legacy NHS England FHIR Implementation Guide based solutions do so at their own risk and on the understanding that no maintenance or support will be available.

Serialisation

Important: Work in progress

The FHIR standard allows a number of serialisations of resources to be used. Ideally, servers will support the two main serialisations – XML and JSON, however there may be cases where this is difficult to achieve.

FHIR-SERIAL-01:

FHIR APIs MUST support JSON serialisation.
- All FHIR endpoints MUST support JSON formatted requests/responses.
- FHIR endpoints MAY 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).

FHIR-SERIAL-02:

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.