Compare software

SmarterMailCyrus IMAP
Freemium

Can be downloaded for free, with paid licences available to buy.

 Free

Free and open source.

Windows, Linux, Web, Self-hosted Linux, Self-hosted
  • Native MAPI support for Outlook without plug-ins
  • Calendars, contacts, tasks, chat and meetings included
  • Mail, calendars and contacts in one server
  • JMAP support alongside IMAP
  • Proprietary, closed-source software
  • Running a mail server requires ongoing administration
  • Complex to configure compared with all-in-one servers
  • No bundled webmail
Downloadable app, Self-hosted Self-hosted
Closed source Open source
License not stated License not stated
Not stated if an account is needed No account needed
Not stated if it works offline Not stated if it works offline

Checked October 1, 2026

Checked September 24, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.