There probably are some very good reasons not to self host your email server but apparently my own, self hosted, email server's uptime over the last decade is now better than that of outlook.com :-D
Quick lets collect all options people have to self host! in addition to docker-mailserver im aware of
I decided to self-host my mail a few weeks ago and ran through all of the big names I'd heard - Mailcow, mailinabox, Stalwart, and Dovecot+Postfix; honestly I didn't like any of them. Stalwart is very corpo, hard to configure (reading the docs[0] confused the shit out of me), and feels vibe-coded. Mailcow and miab push a huge stack onto you in a way that feels hard to modify yourself, e.g. expecting you to allocate ~2GB ram(?) to running ClamAV, and I never managed to get Dovecot+Postfix working properly.
In the end I paved over my Linux VM with OpenBSD and used Dovecot+OpenSMTPD which I found dead simple and so far faultless. I have nothing but kind words for it.
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Mailcow's README is garbage. It tells me nothing about the software while asking for $50-100/m.
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