generated: '2026-07-21'
method: derived
source: openapi/ + https://developer.wunderkind.co/docs/authenticate-api-requests
notes: >-
  Cross-cutting request/response semantics observed across the Wunderkind
  API surface (Email, Identity, UCRM, Event Ingestion on api.wunderkind.co;
  Text Message on api.wknd.ai). Derived from the harvested OpenAPI plus the
  developer-portal docs; Wunderkind publishes no single conventions page.
authentication:
  style: per-surface API keys
  detail: >-
    Private key as "Authorization: apikey {apikey}" on api.wunderkind.co;
    Bearer JWT on the Email API; X-Client-ID/X-Client-Secret header pair on
    api.wknd.ai; public numeric website ID (site ID) for client-side
    endpoints on api.bounceexchange.com.
  artifact: ../authentication/wunderkind-authentication.yml
idempotency:
  supported: false
  notes: >-
    No idempotency-key header or replay-safety contract is documented on any
    Wunderkind API. Text Message sends generate a server-side messageId per
    request; callers correlate via callbackData. Bulk sends report per-item
    success/failure instead of transactional semantics.
pagination:
  style: none
  notes: >-
    The externally documented surface is command/event shaped (sends,
    lookups, subscribes, event ingestion); no list endpoints or pagination
    parameters are published.
field_expansion:
  supported: false
metadata:
  supported: partial
  notes: >-
    Signals webhook payloads and Text API sends carry caller-defined
    passthrough data (WkAdditionalProperties key/value arrays; callbackData
    JSON string on text sends; sendPurpose reporting tag).
request_tracing:
  request_id_header: null
  notes: No documented request-id/trace header. Text sends return a messageId (UUID) used for status lookup.
versioning:
  style: uri-path (v1) on Identity/UCRM; date-versioned OpenAPI on Event Ingestion
  artifact: ../lifecycle/wunderkind-lifecycle.yml
error_envelope:
  style: per-API
  detail: >-
    Email: {error: {message, detail}}; Identity: {name}; Text: {code,
    message, details[]}; Event Ingestion: grpc-gateway rpcStatus {code,
    message, details[]}.
  artifact: ../errors/wunderkind-problem-types.yml
rate_limit_signaling:
  headers: []
  notes: >-
    Documented numeric limits (Email 1000 req/min per API key; Text 300
    req/s per website) with 429 responses; no X-RateLimit-* or Retry-After
    headers are documented.
  artifact: ../rate-limits/wunderkind-rate-limits.yml
webhooks:
  direction: outbound (Signals)
  auth: static headers or Basic auth, plus a published IP allowlist of 20 source addresses
  artifact: ../asyncapi/wunderkind-signals-webhooks.yml