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Zimbra vs Fastmail: catalog facts
Zimbra	Fastmail
Paid Sold in several editions under Zimbra's license terms; see the edition comparison.	Paid Paid subscription with a 30-day free trial that needs no credit card.
Web, Self-hosted	Android, iOS, Web
Mail, calendar and contacts in one web client Can be run on your own servers	Email, calendar and contacts in one service Choice of EU or USA data residency
Aimed at organisations rather than individuals Running a mail server takes administration effort	No free plan after the trial Hosted service, so your mail lives on Fastmail's servers
Self-hosted, Hosted service	Downloadable app, Web application, Hosted service
Closed source	Closed source
License not stated	License not stated
Not stated if an account is needed	Account needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked October 1, 2026	Official website Full listing and sources Checked September 23, 2026

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