> ## Documentation Index
> Fetch the complete documentation index at: https://developer.eka.care/llms.txt
> Use this file to discover all available pages before exploring further.

# List Registry

> Returns every ontology available for codification, the versions of each ontology, and the active indexes backing them. Use this to discover the exact `ontology` and `version` values to send to the linking endpoints.

## About this endpoint

`GET /med-link/registry/` returns every ontology available for codification,
along with the supported versions of each.

Call it before linking to confirm the exact `ontology` and `version` values to
send to [Link Entity](/api-reference/health-ai/medical-entity-codification/link-entity) and
[Link Entities (Batch)](/api-reference/health-ai/medical-entity-codification/link-entity-batch).

## Response fields

| Field          | Description                                                          |
| -------------- | -------------------------------------------------------------------- |
| `ontologies[]` | Available ontologies, each with its `name` and supported `versions`. |

<Tip>
  Use the `ontology` + `version` pairs from `ontologies[]` directly as the
  `ontology` and `version` fields in linking requests.
</Tip>


## OpenAPI

````yaml GET /med-link/registry/
openapi: 3.1.0
info:
  title: Medical Entity Codification API
  version: 1.0.0
  description: >-
    The Medical Entity Codification API (MedLink Named Entity Linking) maps
    free-text medical entities — symptoms, diagnoses, lab tests and drugs — to
    standardised ontology codes such as SNOMED CT, LOINC, ICD-10-CM and Eka's
    medication database.
servers:
  - url: https://api.eka.care
    description: Production
security:
  - authApiKey: []
tags:
  - name: Registry
    description: Discover the ontologies, versions and indexes available for codification.
  - name: Entity Linking
    description: Link free-text medical entities to standardised ontology codes.
paths:
  /med-link/registry/:
    get:
      tags:
        - Registry
      summary: List registry
      description: >-
        Returns every ontology available for codification, the versions of each
        ontology, and the active indexes backing them. Use this to discover the
        exact `ontology` and `version` values to send to the linking endpoints.
      operationId: listRegistry
      responses:
        '200':
          description: The ontologies currently available for codification.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RegistryResponse'
              example:
                ontologies:
                  - name: snomed
                    versions:
                      - 20250401_extended
                  - name: loinc
                    versions:
                      - v1.0
                  - name: medication
                    versions:
                      - v5.0
                  - name: icd-10-cm
                    versions:
                      - comprehend
components:
  schemas:
    RegistryResponse:
      type: object
      required:
        - ontologies
      properties:
        ontologies:
          type: array
          items:
            $ref: '#/components/schemas/OntologyInfo'
    OntologyInfo:
      type: object
      required:
        - name
        - versions
      properties:
        name:
          type: string
          example: snomed
        versions:
          type: array
          items:
            type: string
          example:
            - 20250401_extended
  securitySchemes:
    authApiKey:
      type: http
      scheme: bearer
      description: >-
        Bearer access token issued by the Eka authorization flow. See
        [Authorization](/api-reference/authorization/getting-started).

````