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Cyrus IMAP vs Radicale: catalog facts
Cyrus IMAP	Radicale
Free Free and open source.	Free Free to run on your own server.
Linux, Self-hosted	Self-hosted
Mail, calendars and contacts in one server JMAP support alongside IMAP	Standard CalDAV and CardDAV support Small and light enough for modest hardware
Complex to configure compared with all-in-one servers No bundled webmail	You set up and maintain the server yourself Only handles calendars and contacts, not mail or files
Self-hosted	Self-hosted
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
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.