Documentation Index
Fetch the complete documentation index at: https://docs.omophub.com/llms.txt
Use this file to discover all available pages before exploring further.
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.
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) |
Response
{
"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" }
]
},
{
"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" }
]
}
]
}
]
}
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.
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) |
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 |
See Also
- Overview - full list of operations, supported vocabularies, and extension properties
- CodeSystem search - discovery for the supported system URIs advertised in this CapabilityStatement
