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Rate limits

Every API-key endpoint allows 60 requests per minute, counted per API key in a rolling 60-second window.

Each response carries RateLimit-Limit, RateLimit-Remaining, and RateLimit-Reset. A rejected request also carries Retry-After, and the body repeats the wait as retryAfterSeconds.

The limit is counted before your key is checked
Requests are bucketed by the token in the Authorization header, and that happens before the key is validated. Requests made with a revoked or mistyped key still consume that token's budget, and requests with no Authorization header at all share a single per-IP bucket.
Two different limits return 429
This per-minute limit is not the only one. FaceTime separately caps dialling at 40 unique destinations per calendar day and returns 429 with error_code: FACETIME_DAILY_LIMIT_REACHED. Branch on error_code rather than on the status alone: waiting retryAfterSeconds will never clear the daily cap.
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