Playbook: newsletters at scale

Listmonk + SES for very large lists, without burning reputation.

For lists in the tens of thousands, the Openship mail server is fine. Above roughly 100k, use this pattern (ADR 09).

Stack

Listmonk (self-hosted, per client) as list manager and campaign UI, relaying through Amazon SES ($0.10 per thousand sends). Dedicated sending subdomain per client (news.clientdomain.com) with its own DKIM/SPF/DMARC. Never share reputation with fleet transactional.

Onboarding sequence

1. SES account, verify the sending subdomain, request production access (starts near 50k/day, raise by ticket).
2. Validate the list before any send. Expect 5 to 10 percent dead addresses on an old list. Over 5 percent bounces risks SES suspension.
3. Configure Listmonk SMTP to SES; wire SES bounce/complaint SNS webhooks into Listmonk suppression.
4. Compliance: one-click List-Unsubscribe headers, DMARC on the sending domain, physical address in footer.
5. Warm up: ramp sends over several weeks (engaged segment first), watch Google Postmaster Tools; spam rate stays under 0.3 percent, target under 0.1.
6. Full-list sends only after warmup. A 1.5M send costs about $150 in SES fees.

Red lines

• No cold or purchased lists through this infrastructure, ever. It burns the domain and possibly the SES account.
• Do not point the bulk stream at the fleet mail server IP.