FHIR CapabilityStatement and terminology metadata

const options = {method: 'GET'};

fetch('https://fhir.omophub.com/fhir/{version}/metadata', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

{
  "resourceType": "CapabilityStatement",
  "status": "active",
  "kind": "instance",
  "fhirVersion": "4.0.1",
  "format": ["application/fhir+json", "application/fhir+xml"],
  "date": "2026-04-13",
  "publisher": "OMOPHub",
  "software": {
    "name": "OMOPHub FHIR Terminology Service",
    "version": "1.0.0"
  },
  "implementation": {
    "description": "OMOPHub FHIR Terminology Service - OMOP Standardized Vocabularies",
    "url": "https://fhir.omophub.com/fhir/r4"
  },
  "rest": [
    {
      "mode": "server",
      "resource": [
        {
          "type": "CodeSystem",
          "interaction": [{ "code": "read" }, { "code": "search-type" }],
          "operation": [
            {
              "name": "lookup",
              "definition": "http://hl7.org/fhir/OperationDefinition/CodeSystem-lookup"
            },
            {
              "name": "validate-code",
              "definition": "http://hl7.org/fhir/OperationDefinition/CodeSystem-validate-code"
            },
            {
              "name": "subsumes",
              "definition": "http://hl7.org/fhir/OperationDefinition/CodeSystem-subsumes"
            },
            {
              "name": "find-matches",
              "definition": "http://hl7.org/fhir/OperationDefinition/CodeSystem-find-matches"
            },
            {
              "name": "diff",
              "definition": "https://fhir.omophub.com/fhir/OperationDefinition/CodeSystem-diff",
              "documentation": "OMOPHub custom operation for comparing concepts across OMOP vocabulary releases."
            }
          ]
        },
        {
          "type": "ValueSet",
          "interaction": [{ "code": "search-type" }],
          "operation": [
            {
              "name": "expand",
              "definition": "http://hl7.org/fhir/OperationDefinition/ValueSet-expand"
            },
            {
              "name": "validate-code",
              "definition": "http://hl7.org/fhir/OperationDefinition/ValueSet-validate-code"
            }
          ]
        },
        {
          "type": "ConceptMap",
          "operation": [
            {
              "name": "translate",
              "definition": "http://hl7.org/fhir/OperationDefinition/ConceptMap-translate"
            },
            {
              "name": "closure",
              "definition": "http://hl7.org/fhir/OperationDefinition/ConceptMap-closure"
            }
          ]
        }
      ],
      "interaction": [{ "code": "batch" }]
    }
  ]
}

const options = {method: 'GET'};

fetch('https://fhir.omophub.com/fhir/{version}/metadata', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

{
  "resourceType": "CapabilityStatement",
  "status": "active",
  "kind": "instance",
  "fhirVersion": "4.0.1",
  "format": ["application/fhir+json", "application/fhir+xml"],
  "date": "2026-04-13",
  "publisher": "OMOPHub",
  "software": {
    "name": "OMOPHub FHIR Terminology Service",
    "version": "1.0.0"
  },
  "implementation": {
    "description": "OMOPHub FHIR Terminology Service - OMOP Standardized Vocabularies",
    "url": "https://fhir.omophub.com/fhir/r4"
  },
  "rest": [
    {
      "mode": "server",
      "resource": [
        {
          "type": "CodeSystem",
          "interaction": [{ "code": "read" }, { "code": "search-type" }],
          "operation": [
            {
              "name": "lookup",
              "definition": "http://hl7.org/fhir/OperationDefinition/CodeSystem-lookup"
            },
            {
              "name": "validate-code",
              "definition": "http://hl7.org/fhir/OperationDefinition/CodeSystem-validate-code"
            },
            {
              "name": "subsumes",
              "definition": "http://hl7.org/fhir/OperationDefinition/CodeSystem-subsumes"
            },
            {
              "name": "find-matches",
              "definition": "http://hl7.org/fhir/OperationDefinition/CodeSystem-find-matches"
            },
            {
              "name": "diff",
              "definition": "https://fhir.omophub.com/fhir/OperationDefinition/CodeSystem-diff",
              "documentation": "OMOPHub custom operation for comparing concepts across OMOP vocabulary releases."
            }
          ]
        },
        {
          "type": "ValueSet",
          "interaction": [{ "code": "search-type" }],
          "operation": [
            {
              "name": "expand",
              "definition": "http://hl7.org/fhir/OperationDefinition/ValueSet-expand"
            },
            {
              "name": "validate-code",
              "definition": "http://hl7.org/fhir/OperationDefinition/ValueSet-validate-code"
            }
          ]
        },
        {
          "type": "ConceptMap",
          "operation": [
            {
              "name": "translate",
              "definition": "http://hl7.org/fhir/OperationDefinition/ConceptMap-translate"
            },
            {
              "name": "closure",
              "definition": "http://hl7.org/fhir/OperationDefinition/ConceptMap-closure"
            }
          ]
        }
      ],
      "interaction": [{ "code": "batch" }]
    }
  ]
}

Overview

Returns a FHIR CapabilityStatement describing what operations and resources OMOPHub exposes at a given FHIR version endpoint. This is the first endpoint every conformant FHIR client hits - HAPI FHIR, Firely, Postman collections, and the inspectors built into most FHIR tooling all probe GET /metadata before making any other call.

Path Parameters

string

default:"r4"

string

OMOP vocabulary release; defaults to the active release.

string

Header alternative to vocab_release; the header takes precedence.

FHIR wire version: r4, r4b, r5, or r6. Omit the segment to use R4.

Request

curl "https://fhir.omophub.com/fhir/r4/metadata" \
  -H "Authorization: Bearer YOUR_API_KEY"

Version variants

Path	FHIR version
`GET /fhir/metadata`	defaults to R4
`GET /fhir/r4/metadata`	R4 (4.0.1)
`GET /fhir/r4b/metadata`	R4B (4.3.0)
`GET /fhir/r5/metadata`	R5 (5.0.0)
`GET /fhir/r6/metadata`	R6 (6.0.0)

The response shape is version-adapted - field names follow the conventions of the requested FHIR version.

Response

Response Fields

string

Always CapabilityStatement.

string

Publication status.

string

Capability statement kind.

string

FHIR release represented by this endpoint.

array

Supported FHIR media types.

string

Capability statement publication date.

string

Capability publisher.

object

Server software name and version.

object

Deployment description and canonical URL.

array

REST resources, interactions, and operations exposed by the server. Extended operations appear under each resource’s operation list. FHIR batch Bundle processing is a system interaction and appears as interaction.code: batch.

{
  "resourceType": "CapabilityStatement",
  "status": "active",
  "kind": "instance",
  "fhirVersion": "4.0.1",
  "format": ["application/fhir+json", "application/fhir+xml"],
  "date": "2026-04-13",
  "publisher": "OMOPHub",
  "software": {
    "name": "OMOPHub FHIR Terminology Service",
    "version": "1.0.0"
  },
  "implementation": {
    "description": "OMOPHub FHIR Terminology Service - OMOP Standardized Vocabularies",
    "url": "https://fhir.omophub.com/fhir/r4"
  },
  "rest": [
    {
      "mode": "server",
      "resource": [
        {
          "type": "CodeSystem",
          "interaction": [{ "code": "read" }, { "code": "search-type" }],
          "operation": [
            {
              "name": "lookup",
              "definition": "http://hl7.org/fhir/OperationDefinition/CodeSystem-lookup"
            },
            {
              "name": "validate-code",
              "definition": "http://hl7.org/fhir/OperationDefinition/CodeSystem-validate-code"
            },
            {
              "name": "subsumes",
              "definition": "http://hl7.org/fhir/OperationDefinition/CodeSystem-subsumes"
            },
            {
              "name": "find-matches",
              "definition": "http://hl7.org/fhir/OperationDefinition/CodeSystem-find-matches"
            },
            {
              "name": "diff",
              "definition": "https://fhir.omophub.com/fhir/OperationDefinition/CodeSystem-diff",
              "documentation": "OMOPHub custom operation for comparing concepts across OMOP vocabulary releases."
            }
          ]
        },
        {
          "type": "ValueSet",
          "interaction": [{ "code": "search-type" }],
          "operation": [
            {
              "name": "expand",
              "definition": "http://hl7.org/fhir/OperationDefinition/ValueSet-expand"
            },
            {
              "name": "validate-code",
              "definition": "http://hl7.org/fhir/OperationDefinition/ValueSet-validate-code"
            }
          ]
        },
        {
          "type": "ConceptMap",
          "operation": [
            {
              "name": "translate",
              "definition": "http://hl7.org/fhir/OperationDefinition/ConceptMap-translate"
            },
            {
              "name": "closure",
              "definition": "http://hl7.org/fhir/OperationDefinition/ConceptMap-closure"
            }
          ]
        }
      ],
      "interaction": [{ "code": "batch" }]
    }
  ]
}

$diff is an OMOPHub-specific CodeSystem operation. Batch processing is not a $batch operation: it is the standard FHIR system-level batch interaction, invoked by posting a Bundle to the FHIR base URL. See FHIR Batch Bundle for the supported entry types. The advertised format array includes application/fhir+xml because the server accepts XML requests via content negotiation. Most operations return clean XML; the three Bundle-shaped endpoints (CodeSystem search, ValueSet search, batch) are best-effort in XML and should be called with JSON in practice. See the XML support matrix in the overview for the per-endpoint breakdown.

Response headers

Every response from the FHIR Terminology Service - /metadata included - carries two OMOPHub-specific headers that tell you which OMOP vocabulary release served the request:

Header	Example	Meaning
`X-Vocab-Release`	`2025.2`	Human-friendly release identifier
`X-Vocab-Release-Status`	`active`	Lifecycle status (`ready`, `active`, `deprecated`, `archived`)

Use these headers to confirm which release your client is actually hitting, especially when pinning a specific version via the X-Vocab-Release request header or vocab_release query parameter. See Vocabulary Versions for the full release history.

Content negotiation

GET /metadata respects the same Accept header rules as every other FHIR endpoint - JSON is returned by default; XML is served only when the client strictly prefers it. See the Content Type section of the overview for the q-value semantics.

Errors

HTTP	Issue Code	Cause
401	`login`	Missing or invalid API key

​Overview

​Path Parameters

​Request

​Version variants

​Response

​Response Fields

​Response headers

​Content negotiation

​Errors

​See Also

Overview

Path Parameters

Request

Version variants

Response

Response Fields

Response headers

Content negotiation

Errors

See Also