Guides
Account quotas and limits
The limits that apply to your plan, and what to do when you hit one.
Every limit is documented in Plans and limits. This guide shows how to read them and what to do when you reach them.
Plans at a glance
| Plan | Monthly emails | Daily emails | Domains | Broadcasts | Retention |
|---|---|---|---|---|---|
| Free | 3,000 | 100 | 1 | No | 3 days |
| Pro | 50,000 | No daily limit | 10 | Yes | 30 days |
| Scale | 200,000 | No daily limit | 1,000 | Yes, with a dedicated IP | 90 days |
| Enterprise | Custom | Custom | Custom | Yes, with dedicated IPs | Custom |
The limits that apply to your organization are shown under Billing in the dashboard. The usend team can set different limits for an organization.
How usage is counted
- Every recipient is one unit: an email with 3 addresses across
to,ccandbcccounts as 3. A batch of 100 single-recipient emails counts as 100. Broadcast emails count. - Days and months are in UTC. The monthly quota resets on the first day of the month.
- A broadcast is checked against your remaining quota for the whole audience before it starts.
- Platform mail from usend itself (such as a sign-in verification) does not count.
Other limits
| Limit | Value |
|---|---|
| API requests | 10 per second per API key |
| Recipients per email | 50 (to + cc + bcc) |
| Emails per batch | 100 |
| Attachments per email | 40 MB total |
| Request body | 50 MB |
| Schedule ahead | 30 days |
What it looks like when you hit one
| Limit | Result |
|---|---|
| Daily quota | 429 daily_quota_exceeded |
| Monthly quota | 429 monthly_quota_exceeded |
| Requests per second | 429 with a retry-after header: Rate limits |
| Domain limit | 403 forbidden ("Your Free plan includes 1 domain...") |
| Too many recipients | 422 validation_error |
| Over SMTP | 452 for a quota or recipient limit, 421 for the rate |
What to do
- Daily limit on Free: spread sends out with scheduling, or upgrade under Billing.
- Requests per second: use batch (100 emails in one request) and honor
retry-after. - Domains: you do not need a domain per sender; a verified domain also covers its subdomains (Subdomain or root). Existing domains are never removed when you move to a smaller plan.
- Monthly: upgrade, or contact [email protected] for a custom limit.
- Queue your sends in your app and retry
429responses after theretry-aftertime; do not retry in a tight loop.
Watching usage
Check the dashboard's usage on Billing, and set up a webhook alert for failed sends so a quota hit is not silent.
Bounce and complaint limits
Besides volume, usend watches quality. An organization above 4% hard bounces or 0.08% complaints over 7 days can be suspended, and a burst of bounces or complaints within 24 hours suspends it within minutes: Bounces and suppressions.
Account rules that also apply:
- Confirm your email address before using the dashboard. Disposable addresses cannot sign up.
- One person can own up to three organizations, and cannot create one while an organization they manage is suspended.
- Sensitive changes (a full-access API key, your password, deleting a domain, changing members) ask for a confirmation code: from your authenticator app, or emailed to you.