CapabilityStatement

GET /metadata returns a FHIR CapabilityStatement describing what the running server actually supports. It is generated at request time from the live search-parameter registry and the Implementation Guide packages loaded at startup — not from a static file — so it always reflects that deployment.

Request

curl -sS http://localhost:9090/fhir/r4/metadata | jq

tip

Treat /metadata as authoritative over any documentation, including this site. A deployment that loads Implementation Guides or defines custom SearchParameter resources supports more than the shipped defaults.

Server-level fields

Field	Value on a default deployment
fhirVersion	4.0.1
status / kind	active / instance
format	application/fhir+json, application/fhir+xml, application/fhir+turtle
patchFormat	application/json-patch+json, application/merge-patch+json, application/xml-patch+xml, application/fhir+json, application/fhir+xml
rest[0].mode	server
rest[0].interaction	transaction, batch, history-system
rest[0].operation	the server's operations
implementationGuide	canonical URL per loaded package
software	name and version of the build

Per-resource entries

rest[0].resource carries one entry per resource type the registry knows, which is the full FHIR R4 base set plus anything contributed by loaded IG packages.

Request

# how many resource types this server exposes
curl -sS http://localhost:9090/fhir/r4/metadata | jq '.rest[0].resource | length'

Response

135

Every R4 resource type can be stored, read, and searched. This count is the number of types the server advertises with search parameters; see Resource types.

Each entry reports:

Field	Meaning
interaction	read, vread, update, patch, delete, create, search-type
versioning	versioned — every write appends a retrievable version
readHistory	true — past versions are readable via history and vread
conditionalCreate / conditionalUpdate	true — see Conditional operations
conditionalDelete	single — a conditional delete may match at most one resource
updateCreate	true — PUT to an unknown id creates the resource (update-as-create)
referencePolicy	literal, logical — both Type/id and identifier-based references are indexed — plus enforced while referential-integrity checking on write is enabled (the default)
searchParam	every parameter available for the type, base plus IG plus custom
searchInclude	reference parameters usable as _include targets
searchRevInclude	parameters usable as _revinclude targets
supportedProfile	profiles contributed by loaded IGs, when present

Request

curl -sS http://localhost:9090/fhir/r4/metadata \
  | jq '.rest[0].resource[] | select(.type=="Patient") |
        {conditionalCreate, conditionalUpdate, conditionalDelete, updateCreate, versioning, readHistory, referencePolicy}'

Response

{
  "conditionalCreate": true,
  "conditionalUpdate": true,
  "conditionalDelete": "single",
  "updateCreate": true,
  "versioning": "versioned",
  "readHistory": true,
  "referencePolicy": ["literal", "logical", "enforced"]
}

Useful queries

Confirm a specific search parameter is available before a client relies on it:

Request

curl -sS http://localhost:9090/fhir/r4/metadata \
  | jq '.rest[0].resource[] | select(.type=="Observation") | [.searchParam[].name]'

Response

[
  "_id", "_lastUpdated", "_text", "_content", "_tag", "_profile", "_security",
  "_source", "_language", "_list", "based-on", "category", "code", "date",
  "patient", "subject", "value-quantity"
]

List the operations this server advertises:

Request

curl -sS http://localhost:9090/fhir/r4/metadata | jq '[.rest[0].operation[].name] | unique'

Response

["convert", "document", "everything", "lastn", "meta", "meta-add", "meta-delete", "validate"]

Verify which Implementation Guides loaded successfully:

Request

curl -sS http://localhost:9090/fhir/r4/metadata | jq '.implementationGuide'

Response

[]

An empty array means no Implementation Guides are loaded. See Implementation Guides.

Check the profiles a type is constrained by:

Request

curl -sS http://localhost:9090/fhir/r4/metadata \
  | jq '.rest[0].resource[] | select(.type=="Patient") | .supportedProfile'

Response

null

supportedProfile is absent until an IG contributing profiles for that type is loaded.

Format negotiation

/metadata honours the same content negotiation as every other endpoint:

Request

curl -sS -H 'Accept: application/fhir+xml' http://localhost:9090/fhir/r4/metadata

Response

<?xml version="1.0" encoding="UTF-8"?>
<CapabilityStatement xmlns="http://hl7.org/fhir">
  <status value="active"></status>
  <kind value="instance"></kind>
  <fhirVersion value="4.0.1"></fhirVersion>
  ...
</CapabilityStatement>

In multi-tenant deployments

Requesting /metadata under a tenant prefix returns the same capability set with tenant-aware URLs:

Request

curl -sS http://localhost:9090/t/acme/fhir/r4/metadata | jq '.rest[0].resource | length'

Response

135

See Multi-tenancy.