There is no fixed cap on the number of recipients in an email campaign. Sends of any size are supported, and the system is built to handle large lists without manual intervention.
How large sends work
When you send a campaign, the system compiles your audience from the saved filter or list you selected, deduplicates addresses, and removes anyone who has unsubscribed, bounced, or marked a message as spam. It then fans out individual send events in batches of up to 750 recipients at a time across the queue.
Each batch of up to 80 events is grouped together before hitting the email delivery provider. The system processes up to 20 of those groups per second. This pacing keeps delivery moving quickly while staying within provider rate limits.
Retries and reliability
The send pipeline runs through a background job system with up to 20 automatic retries per message. If a transient error occurs mid-send, the system will retry without re-sending messages that already went out. Idempotency checks prevent duplicate delivery.
What gets filtered out before sending
Regardless of your list size, the following recipients are excluded automatically at send time:
Addresses marked as unsubscribed, bounced, spam complaints, or repeatedly soft-bounced
Addresses on contacts flagged as do not contact
Invalid email addresses
A/B test campaigns
If you use A/B testing, only the percentage of your list you designated for the test receives email during the test window. The winning variant is sent to the remainder after the evaluation period.
Scheduling
You can schedule a campaign for a future date and time. The audience is compiled and the send begins at the scheduled time. The list is finalized at send time, not at the time you schedule, so any contacts added to your filter criteria before the send goes out will be included.