Zarafa
Open Source Collaboration, providing integration with your existing Linux mailserver, native mobile…
19 Alternatives To Zarafa
Citadel
Is a collaboration suite (messaging and groupware).
G Suite
Google’s encompassing suite of cloud-based business apps.
Horde
Horde Groupware is a free, enterprise ready, browser based collaboration suite.
Kolab Community
Kolab Groupware is a secure, scalable, reliable, flexible, full-featured collaboration suite.
Kopano
Sharing & communication software for business
MDaemon Messaging Server
Low cost, easy to use Email Server software for virtual, on-premise, or hosted deployments for…
Microsoft Exchange Server
Microsoft Exchange Server is a messaging and collaborative software product developed by Microsoft.
Office
Collaborate for free with online versions of Microsoft Word, PowerPoint, Excel, and OneNote. Save documents, spreadsheets, and presentations online, in OneDrive. Share them with others and work together at the same time.
OpenChange
OpenChange aims to provide a portable Open Source implementation of Microsoft Exchange Server and…
Outlook
Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Postbox
The Power Email App for busy professionals, like you.
Roundcube
Web-based IMAP email client
SOGo
SOGo is groupware server with a focus on scalability and open standards.
Telegram
Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.
Zimbra
Zimbra is trusted by over 500 million users to increase productivity with a complete set of collaboration tools while maintaining total control over security and privacy.
Zimbra Collaboration Suite
Zimbra Collaboration is an open, secure collaboration tool for email, calendaring, tasks and more.
Zoho One
Zoho is an all-in-one online office suite.
iMail
Fast, safe, heavy mail solution.
iRedMail
A fully fledged, free email server solution, an open source project (GPL v2).