Compare software

Baïkal vs Cyrus IMAP: catalog facts
Baïkal	Cyrus IMAP
Free Free and open source under the GPL v3.	Free Free and open source.
Self-hosted	Linux, Self-hosted
Runs on any basic PHP host Web interface for users, calendars and address books	Mail, calendars and contacts in one server JMAP support alongside IMAP
No built-in calendar or contacts web client for end users Docker installation is only unofficial	Complex to configure compared with all-in-one servers No bundled webmail
Self-hosted	Self-hosted
Open source	Open source
License: GPL-3.0	License not stated
No account needed	No account needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked September 24, 2026	Official website Full listing and sources Checked September 24, 2026

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