Compare software

Cyrus IMAPgrommunio
Free

Free and open source.

 Freemium

Open source, with paid plans listed on the pricing page.

Linux, Self-hosted Linux, Web, Self-hosted
  • Mail, calendars and contacts in one server
  • JMAP support alongside IMAP
  • Native MAPI, EWS and EAS support for Outlook and mobile clients
  • Mail, calendars, chat, video and files on one platform
  • Complex to configure compared with all-in-one servers
  • No bundled webmail
  • Running a groupware server requires administration skills
  • Some features may depend on paid plans
Self-hosted Self-hosted, Hosted service
Open source Open source
License not stated License not stated
No account needed Not stated if an account is needed
Not stated if it works offline Not stated if it works offline

Checked September 24, 2026

Checked October 1, 2026

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