Rate limits

On the starter plan each API key gets 300 requests a minute in total, of which 60 can be sending calls (messages, batch, lookup, verify send, campaign start). Every response includes RateLimit-* headers; on sending calls they describe the sending quota. RateLimit-Reset is the Unix time the window ends. Exceeding a quota returns 429 RATE_LIMITED with Retry-After.

RateLimit-Limit: 60
RateLimit-Remaining: 41
RateLimit-Reset: 1710000060