Account & compliance
Sandbox, limits and quotas
4 min read
Sandbox
New accounts can send live email only to verified members of their own team. Upgrade to a paid plan, or ask support to approve the account, to send to anyone.
Monthly and daily quotas
Your plan sets a monthly number of live emails (Free: 1,000). Test-key emails do not count. You get an email at 80% and 100% of the monthly limit.
Rate limits
Per-second, per-minute and per-hour limits protect deliverability. Over the limit, the API returns 429 with Retry-After; campaigns slow down and continue on their own.
When a campaign pauses
If the daily or monthly quota runs out mid-campaign, it pauses with the reason shown. Resume it after the quota resets or after upgrading.
See Pricing for plan limits.