listmonk

listmonk is a self-hosted newsletter and mailing-list manager written in Go by Kailash Nadh — the same developer behind Metabase contributor tools and Indigo. It was built to handle genuinely large mailing lists without per-contact pricing, and the architecture reflects that priority: a single Go binary backed by PostgreSQL, a configurable pool of SMTP connections for parallel sending, and a clean React-based admin UI for managing subscribers, lists, campaigns, and templates.

The sending engine is the standout feature. listmonk supports multiple SMTP connections simultaneously — for example, splitting sends across Amazon SES and a secondary provider — and tracks bounces, complaints, and unsubscribes through webhooks from the delivery provider. The template system uses Go's standard html/template package, which allows full dynamic content generation per subscriber using their stored custom attributes. Opt-in flows support both single and double confirmation, and the subscription API can be called from any external form or application.

The self-hosted model means listmonk has no SaaS pricing, no contact caps, and no per-send fees. The practical cost is a small VPS (a $6/month Hetzner instance handles hundreds of thousands of sends per campaign) plus the SMTP provider cost — Amazon SES charges $0.10 per 1,000 emails, which makes large lists dramatically cheaper than hosted ESPs. The trade-offs are real: you own infrastructure reliability, backup management, and deliverability reputation. listmonk also does not include the advanced visual journey builders or sophisticated segmentation of full marketing platforms. For developers and technical teams sending newsletters at volume, the economics are hard to argue with.