Email API Rate Limits & Fair Use on Free Plans
Daily send caps, burst limits, and how legitimate products stay well under abuse thresholds.
Free tiers protect shared reputation. Product mail to opted-in users rarely hits limits; cold outreach belongs nowhere near your product domain.
Quick summary
- Each mailbox can send up to 250 emails per day, and API sends count toward the same cap as mail sent by people
- Each API key also has its own per-minute and daily send limits, so a leaked key cannot flood the internet with mail from your domain
- When a key hits a limit the API answers with HTTP 429 and a Retry-After header telling you how long to wait
- Successful responses include X-RateLimit-Limit, X-RateLimit-Remaining and X-RateLimit-Reset headers, so your code can slow down before it hits the limit
- Read the rate-limit headers instead of hard-coding a number
The limits on OquMail
- Each mailbox can send up to 250 emails per day, and API sends count toward the same cap as mail sent by people
- Each API key also has its own per-minute and daily send limits, so a leaked key cannot flood the internet with mail from your domain
- When a key hits a limit the API answers with HTTP 429 and a Retry-After header telling you how long to wait
- Successful responses include X-RateLimit-Limit, X-RateLimit-Remaining and X-RateLimit-Reset headers, so your code can slow down before it hits the limit
Why limits exist on free plans
Everyone on a shared service benefits from its good reputation with Gmail, Outlook and other providers. One customer sending spam would hurt deliverability for all. Limits keep that risk small, and legitimate product mail — receipts, resets and notifications to real users — rarely comes close to them.
Handling limits in your code
- Read the rate-limit headers instead of hard-coding a number
- On a 429, wait for the Retry-After time before trying again, instead of retrying immediately
- Queue non-urgent mail and send it steadily, rather than in one burst
- Send password resets and security alerts first when you are near the limit
What does not belong on your product domain
Cold outreach and bought lists generate complaints, and complaints damage the reputation your receipts and resets depend on. If your product needs to send well over 250 messages a day from one mailbox, contact us to talk about it before you build around it.