Sending to large audiences

Sending to thousands (or tens of thousands) of contacts requires care. A single bad send can damage your sender reputation and affect deliverability for weeks.

Before you send

Verify your list is clean

• Remove contacts who haven't engaged in 90+ days
• Remove known bad addresses (typos, role accounts)
• Check for blocklisted domains

Check your SES limits

AWS SES has sending quotas. In the SES console, check:

• Daily sending quota — maximum emails per 24 hours
• Maximum send rate — maximum emails per second

If your list exceeds your quota, request an increase from AWS before sending.

Warm up if needed

If this is your first large send from this domain, warm up gradually rather than blasting your entire list at once.

Splitting large sends

For very large lists (50,000+), consider splitting into batches:

1. Send to your most engaged segment first (opened or clicked in the last 30 days)
2. Wait a few hours and check for unusual bounce or complaint rates
3. Send to the next batch
4. Repeat

This protects your reputation — if something is wrong (bad list data, content triggers), you catch it early before damaging your domain's standing with inbox providers.

Monitoring during sends

Watch these metrics in real time through your Sendra campaign report and the SES console:

• Bounce rate — if it spikes above 5%, pause and investigate
• Complaint rate — if it exceeds 0.1%, stop immediately
• Delivery rate — should be above 95%