Open Source Alternatives to Microsoft Exchange

An email platform that provides messaging and collaboration services for organizations. This software manages electronic mail, calendars, and contacts, allowing users to communicate and coordinate schedules within a professional or academic environment. It is typically deployed as a cloud service, ensuring that data is synchronized across various devices and accessible from any location. The platform handles mail routing and storage while providing administrative tools for managing user accounts and security policies. It is designed for businesses and educational institutions that require a centralized system for corporate communication and resource scheduling. The service integrates with other productivity tools to facilitate a unified workflow for employees and students.

Whether you want to cut software costs or escape vendor lock-in, these open source alternatives to Microsoft Exchange give you an option you fully own. You can self-host them, so your data stays on infrastructure you control. This page lists 7 open source alternatives to Microsoft Exchange. The most popular are Docker Mailserver, mailcow and Mailu. Most use the GPL-3.0 or MIT license, and 6 offer an official Docker image.