National Terminology Server

The National Terminology Server (NTS) hosts the national terminology content. The content of the NTS is available via the Integration Interface which exposes a HL7TM FHIR® standard endpoint at and is described in the NCTS Conformant Server Applications specification’s FHIR API section.

As a single national instance, the National Terminology Server does not permit write operations, and for availability and performance reasons is not suited to runtime system integration. To support write operations and runtime integration of FHIR, Ontoserver® is available to deploy locally with streamlined content updates via the National Syndication Server

However, the National Terminology Server FHIR endpoint can be used by software to:

  • interrogate and extract data for packaging with software; and
  • support authoring tools, such as Snapper.

The FHIR endpoint is well described in Ontoserver’s documentation and all NTS FHIR responses conform to the NCTS FHIR Profiles documented in the NCTS Content Types specification’s FHIR section.

The NTS is further described in the NCTS National Services specification’s National Terminology Server section. Additionally, the NTS itself describes the capabilities it has been configured to support, via the Capability Statement. The Capability Statement is available at

To help developers get started, we have provided:

  • An open source Java and .NET syndication client implementation which works against the National Syndication Server. This client provides a:
    • Command line client.
    • Maven plugin.
    • Java library.
  • Example REST requests in a Postman collection. These are intended to demonstrate how to integrate with the NCTS, including:
    • Requesting an access bearer token.
    • Querying the integration API.
    • Fetching the syndication feed.

To use these examples, download the collection and environment variables. Import these files into the Postman application and select the “NCTS-R4” environment (latest FHIR version), or NCTS-STU3 environment (previous FHIR version). Before running the examples, please ensure you have created a set of client credentials (within the Clients section located towards the top right of this page) and then set the following variables in the “NCTS-R4” or “NCTS-STU3” Postman environment:

  • auth.client_id: NCTS client credential Client ID
  • auth.client_secret: NCTS client credential Client Secret

For more information on client credential authentication, go to the API Security section of the NTS specification.

/library/NCTS_Postman_Collection.jsonNCTS Postman Collection
/library/NCTS-R4.postman_environment.jsonNCTS Postman Environment (R4)
/library/NCTS-STU3.postman_environment.jsonNCTS Postman Environment (STU3)

The National Terminology Server contains content from LOINC ( LOINC is copyright 1995-2020, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee and is available at no cost under the license at LOINC® is a registered United States trademark of Regenstrief Institute, Inc.