Proton Mail vs Roundcubemail
Proton Mail and Roundcubemail are both email server software. Proton Mail is a commercial product from Proton AG. Roundcubemail is open source under GPL-3.0, with 7.3k GitHub stars.
Which to pick
- Pick Proton Mail when
- Privacy is your first concern and you want encrypted email, especially between Proton users.
- Pick Roundcubemail when
- You run an IMAP server and need a dependable webmail front end.
Side by side
End-to-end encrypted email from Switzerland, bundled with Proton's calendar, drive, VPN and password manager.
A browser-based IMAP webmail client with address book, folders, filters and plugins, widely bundled with hosting control panels.
Desktop email clients need the paid Bridge app, and encryption limits server-side search and integrations.
A frequent target for attacks, so it must be kept patched.
Production-ready (both)
Cloud service, desktop app and mobile app
Self-hosted server
Not published
PHP and JavaScript
Closed source, sold by Proton AG
Open source, GPL-3.0 (strong copyleft)
Closed source: you use it under the maker's terms and cannot change or resell the code.
Use inside your business is unrestricted, but anything you distribute that includes it must be released under the same license.
12k Wikipedia readers a month on phones
7.3k GitHub stars
Not known
Established: started 14 years ago, latest release 1.7.5.
Other comparisons
More email servers and webmail
Both sides were judged on 2026-11-03 from makers' descriptions, Wikipedia, READMEs and GitHub data. License, age and popularity lines are worked out directly.