Free and Open Source Self-Hosted Newsletter System

The system is fairly complete and ready to use out of the box. Feel free to check it out and deploy it if needed (though you'll need to set up your own email service—for example, Amazon SES is a solid option, and you can apply for it yourself at roughly $1 per 10,000 emails). The main purpose of this system is to let you manage a user list and bulk-send newsletter-style content, with built-in tracking for metrics like open rates and more. You're welcome to dive deeper and explore its features on your own.

Open-source links:

https://listmonk.app/

https://github.com/knadh/listmonk