Listmonk

listmonk is a self‑hosted newsletter and mailing‑list manager that runs as a single binary and stores data in PostgreSQL. It provides a web dashboard for creating and sending campaigns, managing one‑way mailing lists with single or double opt‑in, and segmenting subscribers using SQL expressions. The tool includes built‑in analytics that display delivery metrics, bounces, and link clicks, and a templating system based on Go’s language language with options for drag‑and‑drop, WYSIWYG, Markdown, or raw HTML editing.

The application is designed for high throughput, using multi‑threaded processing and multi‑SMTP queues with configurable rate limiting. It can handle millions of subscribers while keeping CPU and memory usage low, and it offers an API for sending transactional messages as well as webhooks for extending delivery to SMS, WhatsApp, push notifications, or other channels.

listmonk is open source under the AGPL‑3.0 license and can be deployed via Docker or a compiled binary. It targets developers and organizations that need a performant, extensible mailing system without relying on external services, providing full privacy controls, role‑based access, and optional OIDC SSO.