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Zoho CalendarSOGo
Freemium

Free to start, with paid Zoho plans for business features.

 Free

Free and open source; paid premium support is offered separately.

Web Web, Self-hosted
  • Team calendars with availability checks
  • Built-in appointment and resource booking
  • Webmail, calendars and contacts in one self-hosted server
  • CalDAV, CardDAV and ActiveSync support for native and mobile clients
  • Hosted service, with data stored by Zoho
  • Most useful inside the wider Zoho ecosystem
  • Needs existing mail and directory servers to integrate with
  • Outlook support depends on a separate CalDAV synchronizer
Web application Self-hosted
Closed source Open source
License not stated License: GPL-2.0-or-later / LGPL-2.0-or-later
Account needed Not stated if an account is needed
Not stated if it works offline Not stated if it works offline

Checked October 2, 2026

Checked September 23, 2026

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