Create iframe URL
Mints a single-use signed URL that loads the embedded review UI in an iframe, so the token itself never reaches the parent frame. Requires a plan that includes the embedded review UI; other plans get a 403.
Authentication
Headers
Request
Optional opaque, stable end-user identifier, with the same contract as
external_user_id on POST /api/embed/sessions. It is
carried onto the session the exchange returns.
Reserved, with the same contract as display_name on
POST /api/embed/sessions, including that it requires
external_user_id. It is carried onto the session the exchange
returns.
Response headers
The API surface version the server resolved for this request. Always present, regardless of whether the client supplied the request-side SpreadSpace-Version header. Default: 2026-07-19.
Requests left in the current window. Suppressed on 429 responses produced outside the rate limiter (for example a usage throttle), where a remaining budget would be misleading.
Seconds until a guaranteed-fresh window.
The active policy in limit;w=window-seconds form.
Response
Echo of the request’s display_name as stored, with control
characters stripped and the value trimmed. Omitted when the request
carried no label.