listmonk

listmonk is a standalone, self-hosted newsletter and mailing list manager for sending campaigns and transactional email. It stores its data in PostgreSQL and is packaged as a single binary.

It runs as a web app with a modern dashboard. Install it with Docker or by downloading the binary, then configure it and connect it to your Postgres database. The app also includes SMS gateway support.

listmonk is free and open source software licensed under AGPLv3. It is built in Go with a Vue frontend and Buefy for the UI. Self-hosted deployment is available through Docker or a binary install, so the service can run on infrastructure you manage.