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Terminology services

SNOMED CT Terminology Services provide an effective way of implementing SNOMED CT by enabling SNOMED CT content to be searched and queried via an API (application programming interface).

A rapid and effective way of deploying SNOMED CT in a national or local implementation is to use a SNOMED CT enabled terminology server. A SNOMED CT terminology server simplifies the development of clinical applications that use SNOMED CT, by providing optimized terminology services through an APIs (Application Programming Interfaces). Terminology services may include:

  • Searching for SNOMED CT content using term matching, the hierarchy, or defining relationships (see Snowstorm Search Guide),

  • Retrieving information about a given concept, including descriptions for a given dialect, supertypes, subtypes and defining relationships,

  • Executing Expression Constraint Queries (ECL) on a particular SNOMED CT edition, and

  • Accessing maps to/from SNOMED CT and other reference set information.


Terminology servers can either import data from a SNOMED CT release package, or periodically synchronise its content with another terminology server. The loaded SNOMED CT content can then be made available to browsers or electronic health records using a convenient API that implements terminology best practices. Using a terminology server in your implementation can save time, by removing the need to implement these services from scratch. The use of standardized APIs can also simplify their integration into end user applications.

To learn more about using terminology services, please enrol in our SNOMED CT Terminology Services Course (free for Members).


SNOMED International develops and maintains Snowstorm, a SNOMED CT terminology server built on top of Elasticsearch, with a focus on performance and enterprise scalability. Snowstorm provides the terminology server API for a range of SNOMED CT tools used by SNOMED International, including the SNOMED CT Browser and the SNOMED CT Authoring Platform.

As an open-source tool, Snowstorm can be installed locally to provide a terminology services API to clinical applications.

The main features of the Snowstorm Terminology Server include:

  • Open source, based on a modern open-source stack, Elasticsearch, Spring Boot, Docker

  • HL7 FHIR API, capable of hosting SNOMED CT, LOINC, ICD-10, ICD-10-CM and many other code systems

  • Multi-lingual search and content retrieval

  • Fully ECL v2.1 compliant

  • Full history (depends on full RF2 import)

  • SNOMED specific API for Extension Maintenance

To deploy Snowstorm in a clinical system, please visit the Snowstorm Github repository to learn how to install your own local instance.

Other terminology servers

Other SNOMED CT terminology servers are available, as listed below. Please note that these terminology servers may use different licensing models and APIs (e.g. a standard HL7 FHIR API, or a proprietary API).

Hermes Terminology Server, UK

Ontoserver, CSIRO, Australia

PHAST FHIR Terminology Server, France

Snowray Terminology Service, B2i Healthcare

WCI SNOMED CT Terminology Server, West Coast Informatics

This list of terminology servers is provided in alphabetical order. To request the addition or removal of a terminology servers to/from this list, please submit a request via the 'Feedback' button at the bottom of this page.

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