HTTP 429 · type rate_limit_error · retryable true

defaultMessage Too many requests. Retry after the indicated delay.

rate_limit_exceeded

You hit a short-window rate limit (requests or egress), not only the daily plan quota.

What to do

1. Honour Retry-After / X-RateLimit-* headers when present.
2. Reduce concurrency; use a queue on your side instead of bursting.
3. Prefer fewer larger broadcasts over thousands of parallel single sends when possible.
4. Do not spin-retry immediately — wait the indicated interval.
5. Contact support if limits look stuck after sustained idle time.