Best Expanding Communication Alternatives & Competitors in 2024

Microsoft Exchange Server is a messaging and collaborative software product developed by Microsoft.

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.

The #1 email warming service to improve your deliverability by generating realistic and meaningful engagement to your emails. Easy-to-use solution to help you land in the main inbox instead of the spam folder.

Visit website paid $19.5 / Monthly (Pro)

hMailServer is a free e-mail server for Microsoft Windows.

Fast, safe, heavy mail solution.

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.

OBM is a free messaging and collaboration platform useful for just a couple to many thousands of users with strong support for mobile devices.

Is a collaboration suite (messaging and groupware).

OpenChange aims to provide a portable Open Source implementation of Microsoft Exchange Server and...

Google's encompassing suite of cloud-based business apps.

Axigen is an integrated email, calendaring & collaboration platform, built on a Linux mail server technology.

SOGo is groupware server with a focus on scalability and open standards.

Open Source

A fully fledged, free email server solution, an open source project (GPL v2).

Open Source

Kolab Groupware is a secure, scalable, reliable, flexible, full-featured collaboration suite.