Listmonk

Listmonk is a self-hosted newsletter and mailing list manager built for people who want full control over their email infrastructure. It ships as a single binary with a minimal footprint, making it practical to run on modest hardware without sacrificing throughput. If you're looking for a Mailgun alternative or a self-hosted replacement for services like Beehiiv or MailerLite, listmonk covers the full stack from campaign management to transactional messaging.

The core use case is sending large-scale email campaigns. A production instance can send 7+ million emails with CPU usage under a single core and peak RAM around 57 MB. That's genuinely lean.

Key capabilities:

• Subscriber management across single and double opt-in lists, with SQL-based querying and segmentation for precise targeting
• Multi-SMTP queues with multi-threaded, high-throughput sending and sliding window rate limiting for fine-grained control
• Transactional email API to send arbitrary messages using pre-defined templates, triggered programmatically
• Messenger interfaces extend delivery beyond email to SMS, WhatsApp, and FCM push notifications via HTTP webhooks
• Template engine with 100+ functions, logic expressions, and support for drag-and-drop, WYSIWYG, Markdown, or raw HTML composition
• Built-in analytics covering campaign performance, bounce tracking, and top link clicks
• Media library with S3-compatible backend support
• OIDC SSO authentication with granular roles, permissions, and API tokens

The backend is written in Go, the frontend in Vue, and the whole thing is licensed under AGPLv3. Compared to tools like Postal or Sendportal, listmonk stands out for its raw throughput and the breadth of its API coverage, which makes it a practical foundation for custom workflows and integrations.