phplist3

phpList was sending newsletters before most marketing SaaS existed, and it still does it at a scale that surprises people. Millions of recipients from a PHP application on an ordinary server, with subscribe pages, list segmentation, bounce processing, and campaign statistics.

PHP and MySQL, plus a cron job to process the send queue. That cron detail catches more first time installers than anything else in the stack, because campaigns will sit there looking perfectly scheduled and never actually move. Shared hosting works fine, which is unusual in this category and is a real advantage if you are not running containers.

Self-hosting is free under AGPLv3. The hosted service at phpList.com prices along two odd axes but prices cheaply: $8 a month for 500 subscribers with a million messages, a $1 plan covering 9,000 messages to 3,000 subscribers, and a free tier of 300 messages against an unlimited subscriber count. Pick whichever axis matches how you actually send.

The catch is the interface. It is dated in a way no amount of theming repairs, and the documentation assumes you are comfortable editing a config file. For a modern UI doing the same job, look at knadh/listmonk. For twenty years of proven behavior against every mail provider that matters, stay here.