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WildDuckCyrus IMAP
Free

Free open-source software that you host yourself.

 Free

Free and open source.

Linux, Self-hosted Linux, Self-hosted
  • Horizontal scaling with no single point of failure
  • Full IMAP4rev1 support with many extensions
  • Mail, calendars and contacts in one server
  • JMAP support alongside IMAP
  • Needs MongoDB, Redis and separate SMTP components
  • Aimed at large deployments rather than small personal servers
  • Complex to configure compared with all-in-one servers
  • No bundled webmail
Self-hosted Self-hosted
Open 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.