Transactional & SMTP
Email API Rate Limits and How to Work Within Them
Email API rate limits come in four layers - request rate, sending quota, SMTP concurrency, and receiving-ISP throttling - and each returns a different error. This guide covers reading rate-limit headers, which responses to retry and which never to, backoff with jitter, queue architecture, and separating transactional from bulk traffic.
Sep 19, 20269 min read