Limits
Plan caps are enforced. There is no separate daily cap.
Full prices are on /pricing. Over a cap, the API returns HTTP 402 plan_limit_exceeded with upgrade_url.
| Plan | Inboxes | Emails / month | Custom domains |
|---|---|---|---|
| Free ($0) | 5 | 5,000 | 0 |
| Starter ($12/mo) | 25 | 25,000 | 15 |
| Pro ($99/mo) | 300 | 250,000 | 200 |
One outbound API send counts as one email, regardless of recipient count. Replaying the same client_id does not count again. Inbound mail does not count against the send cap.
Overage prices, if present on the Stripe subscription, raise the cap: $1 / inbox, $1 / domain, $1 / 1,000 emails. The API does not meter past the cap on its own.
Accounts already in the database when the billing columns were added are grandfathered and are not subject to these inbox or send caps. New accounts start on Free.
Attachments: 10 files, 4 MiB each, 5 MiB total message (Cloudflare Email Sending limit). Cooper does not publish a separate requests-per-minute API throttle. Abusive traffic is handled under the abuse policy. Vercel and Cloudflare may apply their own edge limits.
Custom-domain counts are plan terms. The DNS wizard does not yet persist a verified domain record, so domain count is not rejected with 402 today. Volume above Pro: ops@avatar33.com.