Sendy is a very good self-hosted mail system, and does a good job of replacing Mailchimp or equivalent, dramatically cutting costs. When you make a list, you can set your “Unsubscribe behavior” to be “Double Opt-Out”. “Double opt-out” is a good thing. It means that when someone follows a link from your email, it asks them “are you sure?” and gives them a button to confirm. That means that a virus checker following links in incoming mail won’t inadvertently unsubscribe users....
