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.
Mailu - Mailu is a simple yet full-featured mail server as a set of Docker images.
Google Workspace - Google's encompassing suite of cloud-based business apps.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Microsoft Exchange Server - Microsoft Exchange Server is a messaging and collaborative software product developed by Microsoft.
MailEnable - MailEnable is a Windows based mail server and email server program that is packed with the state of the features and functions like antivirus and spam filtering system, webmail management system, cardDAV, CalDAV and much more.