> ## Documentation Index
> Fetch the complete documentation index at: https://docs.haau3.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Capability statement

> FHIR `[base]/metadata`. Returns the `CapabilityStatement` for this service, or a `TerminologyCapabilities` when called with `?mode=terminology` — which lists the code systems served, and names those that are recognised but not served.



## OpenAPI

````yaml /api-reference/openapi.json get /v1/fhir/r4/metadata
openapi: 3.1.0
info:
  title: haau3 Platform API
  version: 1.0.0
  description: >-
    The haau3 platform API (non-PHI). Endpoints require a free API key — send it
    as `Authorization: Bearer <key>`. Requests without a valid key return 401.
    Create a key in the dashboard at https://platform.haau3.com.
servers:
  - url: https://api.haau3.com
    description: Production
security:
  - bearerAuth: []
tags:
  - name: Scheduling
    description: Provider availability (SMART Scheduling Links) — slots and publishers.
  - name: Terminology
    description: FHIR terminology operations — CodeSystem lookups against LOINC.
  - name: Provider directory
    description: >-
      FHIR Practitioner and PractitionerRole, resolved from the national
      provider directory. Resolution, not discovery: bring an NPI and get what
      the directory publishes for it.
paths:
  /v1/fhir/r4/metadata:
    get:
      tags:
        - Terminology
      summary: Capability statement
      description: >-
        FHIR `[base]/metadata`. Returns the `CapabilityStatement` for this
        service, or a `TerminologyCapabilities` when called with
        `?mode=terminology` — which lists the code systems served, and names
        those that are recognised but not served.
      operationId: fhirMetadata
      parameters:
        - name: mode
          in: query
          required: false
          schema:
            type: string
            enum:
              - terminology
          description: >-
            Pass `terminology` for a `TerminologyCapabilities` resource instead
            of the `CapabilityStatement`.
      responses:
        '200':
          description: >-
            A FHIR `CapabilityStatement`, or a `TerminologyCapabilities` when
            `mode=terminology`.
          content:
            application/fhir+json:
              schema:
                type: object
                additionalProperties: true
        '401':
          description: Missing or invalid API key.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/AuthError'
components:
  schemas:
    AuthError:
      type: object
      properties:
        error:
          type: string
          examples:
            - API key required
        message:
          type: string
      required:
        - error
        - message
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: >-
        Your platform API key (`haau3_sk_…`), sent as `Authorization: Bearer
        <key>`.

````