Rate limits

• 120 requests per minute per key (a key may carry its own quota).
• Plus 600 requests per minute per IP.

Every response carries the limit's state:

Header	Meaning
X-RateLimit-Limit	Calls allowed in the window
X-RateLimit-Remaining	Calls left
X-RateLimit-Reset	Seconds until the window resets

Beyond the limit you get 429 RATE_LIMITED with Retry-After (seconds); wait that long and retry.

Retries

There is no Idempotency-Key in v1. When you resend a request after a network error, the record itself prevents duplicates: a second booking for the same slot gets 409 SLOT_CONFLICT, a second payment for the same booking 409 ESCROW_EXISTS (with the existing payment in the answer).