
SOGo
Scalable groupware server with webmail, calendars, and contacts
2.2k stars 320 forks last commit first released GPL-2.0
Actively maintained
Last commit 13 Aug 2026.

SOGo is a fast, scalable groupware (collaboration) server that provides webmail, calendars, and address books through a modern web interface and open protocols. It is designed to sit alongside existing mail infrastructure and give users a unified experience across desktop and mobile clients.
Key Features
- AJAX-based web interface for mail, calendars, and contacts
- Standards-based interoperability with existing systems via IMAP, CalDAV, and CardDAV
- Mobile synchronization support via Microsoft ActiveSync
- Resource sharing, delegation, and permission handling for calendars and address books
- Works with many native clients without requiring plugins (depending on client capabilities)
Use Cases
- Provide a webmail and groupware frontend on top of an existing IMAP mail server
- Replace proprietary groupware with an open-standards collaboration server for organizations
- Offer shared calendars/contacts with permission management for teams and communities
Limitations and Considerations
- Requires integration with external mail services (for example IMAP/SMTP servers) rather than being a complete mail server by itself
SOGo is a strong fit for deployments that prioritize open standards, scalability, and broad client compatibility. It can be used as a central collaboration layer to provide consistent mail, calendar, and contact access across many devices and clients.
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