Fastmail vs Roundcubemail
Fastmail and Roundcubemail are both email server software. Fastmail is a commercial product from Fastmail Pty Ltd. Roundcubemail is open source under GPL-3.0, with 7.3k GitHub stars.
Which to pick
- Pick Fastmail when
- An individual, family or small business wants fast, private email on its own domain without Google or Microsoft.
- Pick Roundcubemail when
- You run an IMAP server and need a dependable webmail front end.
Side by side
Paid, ad-free email hosting with calendars, contacts, custom domains and masked email addresses, built on open standards (IMAP, JMAP, CalDAV).
A browser-based IMAP webmail client with address book, folders, filters and plugins, widely bundled with hosting control panels.
No office suite or file storage included, and data is held in Australia and the US.
A frequent target for attacks, so it must be kept patched.
Production-ready (both)
Cloud service and mobile app
Self-hosted server
Not published
PHP and JavaScript
Closed source, sold by Fastmail Pty Ltd
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.
586 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.