Mail-in-a-Box vs Proton Mail
Mail-in-a-Box and Proton Mail are both email server software. Mail-in-a-Box is open source under CC0-1.0, with 15k GitHub stars. Proton Mail is a commercial product from Proton AG.
Which to pick
- Pick Mail-in-a-Box when
- You want your own email on a dedicated VPS with as few decisions as possible.
- Pick Proton Mail when
- Privacy is your first concern and you want encrypted email, especially between Proton users.
Side by side
A setup script that turns a fresh Ubuntu server into a complete mail server with Postfix, Dovecot, Roundcube webmail, Nextcloud contacts and calendars, spam filtering, DNS and TLS.
End-to-end encrypted email from Switzerland, bundled with Proton's calendar, drive, VPN and password manager.
It takes over the whole machine, allows almost no customisation, and depends on a specific Ubuntu LTS release.
Desktop email clients need the paid Bridge app, and encryption limits server-side search and integrations.
Production-ready (both)
Self-hosted server
Cloud service, desktop app and mobile app
Python, Shell, Postfix, Dovecot, Roundcube and Nextcloud
Not published
Open source, CC0-1.0 (public domain)
Closed source, sold by Proton AG
You can take the code into anything, including a product you sell, with no conditions.
Closed source: you use it under the maker's terms and cannot change or resell the code.
15k GitHub stars
12k Wikipedia readers a month on phones
Established: started 13 years ago, latest release v77.
Not known
Other comparisons
More email servers and webmail
Both sides were judged on 2026-11-06 from makers' descriptions, Wikipedia, READMEs and GitHub data. License, age and popularity lines are worked out directly.