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Cyrus IMAP vs Mailu: catalog facts
Cyrus IMAP	Mailu
Free Free and open source.	Free Free and open source.
Linux, Self-hosted	Linux, Self-hosted
Mail, calendars and contacts in one server JMAP support alongside IMAP	Webmail and admin interface included Per-domain delegation and quotas
Complex to configure compared with all-in-one servers No bundled webmail	Requires Docker Releases are infrequent
Self-hosted	Self-hosted
Open source	Open source
License not stated	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.