Control

Unbound is pretty easy if you have experience with editing config files.

I use a combination on ProtonMail and Mailgun. I only have a few automated messages going out with mailgun a month so it’s essentially free. I also started using mattermost as a notification channel for different things as well. It has the same API as slack, so you can hook it up to pretty much anything you can hook slack up to.

Have you talked to someone at twilio about a high volume discount?