Access tokens (Authorization: Bearer …)
Allow-list of accepted access tokens. Missing/unknown token → the documented 401 envelope (§2.2). userId → collector_id / webhook user_id; clientId → preference client_id. A TEST- token yields live_mode:false.
Overrides
Webhook "Secret signature" (signs x-signature, §6.1) and the fallback notification URL.
Preferences (Checkout Pro)
Open the hosted page to pick an outcome, or drive payments directly.
Payments
approve / reject / pending / refund / re-notify / corrupt-signature — bypass the test matrix.
Webhook deliveries
Requests from the backend
Danger zone
wipes payments, logs and every runtime override — back to configured defaults