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Find out how to integrate systems to enable electronic booking with the NHS e-Referral Service (e-RS), including how to achieve compliance, attain secure coupling and support safe business process interactions.

Future integration roadmap

Our future integration developments are based on your feedback. The e-Referral Service (e-RS) roadmap includes these enhancements.

These developments ensure that the service is continually improved to make it easier, quicker and more efficient for third party solutions to connect and use.


We aim to build upon the current, supported message interfaces, which were transitioned from Choose and Book, extending these with new Application Programming Interfaces (APIs). The service is dependent on other national components, such as:

  • the Patient Demographic Service (PDS) as the master source of patient demographics
  • Spine Directory Services (SDS) for NHS organisational structures
  • user authentication, security and naming services
  • interface specifications such as message header and transportation standards
  • The Transaction Messaging Service (TMS)


We support N3-based HL7 message interactions from the NHS Connecting for Health Message Implementation Manual (MiM) version 2.3 and from MiM version 3.1.09. Suppliers must support Ebooking interactions either from MiM 2.3 or MiM3.1.09, but can support other MiM versions for other interactions such as PDS. MiM2.3 is supported for backward compatibility only, with partners new to compliance, expected to be MiM3.1.09 compliant.

Other technical messaging documents can be found on the archived Choose and Book site.


The development of the N3 based interface approach is influenced by RESTful service interfaces and the emerging HL7 FHIR (Fast Healthcare Interoperability Resources) standard. The e-RS roadmap shows the timetable of planned system enhancements.

API integration phase 1

This has provided the foundation to support initial clinical system integration. The initial Clinical Referral Information (CRI) APIs are being evaluated with pilot suppliers and will support the transfer of clinical documents within hospital clinical systems. The CRI API can also potentially be used by providers who have Referral Assessment Services (RAS) on e-RS to support the patient registration process. Find out more about the guidance on using APIs with RAS.

API integration phase 2

This is now represented at a more detailed level within the new Integration Roadmap for the 2017/18 financial year. This will enhance the API tools to support referral system integration and provide improved clinical triage functionality to allow clinical system providers to integrate with the Service.

The ecosystem to support partner's API consumption is being finalised. This will provide user information and documentation on the engagement process, API architecture, test environments, FHIR resources and other development resources. The ecosystem is available through The Health Developer Network.

Find out about the integration of Clinical Referral Information by reading our case study about Imperial College Healthcare.


Further information on achieving connectivity and compliance with e-RS can be found at the NHS Business Partners programme.

Last edited: 12 December 2019 11:40 am