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.
Qrvey - Embedded Analytics built exclusively for SaaS applications.
iRedMail - A fully fledged, free email server solution, an open source project (GPL v2).
DevicePilot - DevicePilot is a universal cloud-based software service allowing you to easily locate, monitor and manage your connected devices at scale.
mailcow - An open source mailserver suite.
AnswerRocket - AnswerRocket is a search-powered analytics that makes it possible to get answers from business data by asking natural language questions.