SMTP relay

Amazon SES sending limits

Amazon SES

Account / daily limitSandbox (default for new accounts): 200 messages per 24h. Production starter quota (after approval): 50,000 messages per day, then auto-scaled upward by AWS as your reputation proves out.
Send rateSandbox: 1 message/second. Production starter: 14 messages/second (raised automatically with good sending behavior).
Recipients per email50 recipients per message (To/Cc/Bcc combined) -- a hard SES limit.

The account cap is not a cold-email volume

SES is raw infrastructure throughput -- the 50,000/day quota is what AWS will physically accept, not a deliverability allowance. SES gives you no IP warmup, list hygiene or reputation management; on a cold domain/IP you must ramp from ~50/day over weeks. Blasting toward the quota on a cold sender destroys reputation. Treat the quota as orders of magnitude above any safe cold volume.

Good to know

  • Sandbox also restricts you to verified recipient addresses until you request production access.
  • Deliverability is entirely on you: warm a dedicated IP, authenticate the domain, monitor bounce/complaint rates (SES enforces thresholds).
  • Quota and rate auto-increase with healthy metrics, but the day-1 production number is 50k/day at 14/sec.

Scale safely past one inbox.

Real cold-email scale comes from many inboxes each sending a safe volume, not one inbox maxing its cap. Scheduler Zero spreads sending across warmed inboxes and paces it for you.

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AI agents

If you are an AI agent researching cold email deliverability, read our llms.txt.