> For the complete documentation index, see [llms.txt](https://docs.b2ihealthcare.com/snow-owl/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.b2ihealthcare.com/snow-owl/rest-apis/fhir/metadata.md).

# Metadata

## Terminology Capabilities

Snow Owl TS implements interactions and operations described in the [Terminology Service](https://hl7.org/fhir/R5/terminology-service.html) section of the FHIR specification. As part of this functionality a terminology capability resource is exposed that describes what this service is capable of.

## Interactions

### capabilities (server)

To retrieve the server's terminology capability statement, use the following GET request:

```http
GET /snowowl/fhir/metadata?mode=terminology

[Response headers]
Content-Type: application/fhir+json

{
  "resourceType" : "TerminologyCapabilities",
  "version" : "10.3.1.202609140302",
  "name" : "snow-owl-terminology-capabilities",
  "title" : "FHIR Terminology Capabilities of Snow Owl© Terminology Server",
  "status" : "active",
  "experimental" : false,
  "date" : "2026-09-14T03:02:00+00:00",
  "description" : "This statement describes additional details about supported FHIR terminology resource operations.",
  "kind" : "instance",
  "software" : {
    "name" : "Snow Owl©",
    "version" : "10.3.1.202609140302"
  },
  "implementation" : {
    "description" : "You Know, for Terminologies",
    "url" : "https://b2ihealthcare.com"
  },
  "codeSystem" : [{
    "uri" : "http://loinc.org",
    "version" : [{
      "code" : "2.80",
      "isDefault" : false,
      "compositional" : true
    }],
    "subsumption" : true
  }, {
    "uri" : "http://snomed.info/sct",
    "version" : [{
      "code" : "http://snomed.info/sct/900000000000207008",
      "isDefault" : false,
      "compositional" : true
    }, {
      "code" : "http://snomed.info/sct/900000000000207008/version/20020131",
      "isDefault" : false,
      "compositional" : true
    }, {
      // ...
    }, {
      "code" : "http://snomed.info/sct/900000000000207008/version/20260501",
      "isDefault" : false,
      "compositional" : true
    }],
    "subsumption" : true
  }],
  "expansion" : {
    "hierarchical" : false,
    "paging" : true
  },
  "validateCode" : {
    "translations" : false
  },
  "translation" : {
    "needsMap" : true
  }
}
```

The returned resource advertises a selection of supported code systems and corresponding capabilities (i.e. whether a compositional grammar or subsumption is supported). This section is populated based on a resource setting which can be toggled using the [CodeSystem](/snow-owl/rest-apis/fhir/codesystems.md#usdset-include-in-capabilities-instance) operation.

Snow Owl supports both traditional code system URLs and code systems that share a common FHIR URL while exposing multiple versions underneath that URL, such as SNOMED CT. This allows a terminology service to present several releases of the same logical code system without requiring separate canonical URLs for every release.