I've been using maddy.email running quietly on my RPi for a couple of years now. I think it's 'simpler' than mail-in-a-box because it implements IMAP, SMTP, all

I've been using maddy.email running quietly on my RPi for a couple of years now. I think it's 'simpler' than mail-in-a-box because it implements IMAP, SMTP, all in one server which can be backed by a database, instead of managing installation and updates of many different programs. It also does DKIM automatically and uses ACME/LetsEncrypt to automate certificate management. It doesn't have as many features as mail-in-a-box though for a example no webmail or Cal/CardDAV, so I have to run those separately. It would be great to extend the project Another similar project is stalw.art mail server. I haven't used that yet but it looks promising, and it supports JMAP (a possible IMAP successor)