Mail-in-a-Box vs poste.io

It does not need its own machine

Mail-in-a-Box turns a machine into a mail server. poste.io is one container on a machine that is already doing something else.

Download and try it Move me to poste.io Unlimited domains. Unlimited mailboxes. 349$/year PRO.

Where they differ

poste.io Mail-in-a-Box
The machine Shared with your other services Expected to be dedicated
DNS Use the DNS you already have Runs its own
Upgrade Replace one image Re-run setup for each release
Administration Domain admins and mailbox owners A single administrator

The same on both: Dovecot IMAP/POP3, Roundcube webmail, Web administration, REST API, Unlimited domains and mailboxes.

Being fair about it

Mail-in-a-Box is a great project and the fastest way to turn a fresh VPS into a complete mail server. Mail-in-a-Box also runs your DNS, which is one less thing to arrange.

If the mail server has to share a host with everything else you run, poste.io may be a better fit.

What you get either way

Download and try it See pricing The free edition is the same container.