Alternatives to Microsoft Exchange Server for all platforms with Open Source License

Kopano

Kopano puts an email, video meetings, calendaring, and file sharing solution within one single interface. Kopano helps you work smarter with people within and outside...
- Scalable, open source with a great UX and it has all the features I need bobsp • Feb 2017
- Stable and cheap backend, flexible frontend support, open source, in full control of your data marcski • Feb 2017
- Kopano has scalable backend and can do full MAPI server and clientside. The Webapp and Deskapp has intuitive and modern UI/UX. hn1 • Jan 2017 • 1 agrees and 1 disagrees
- I tried a lot of MS alternatives, OX, Zimbra, Zentyal, but what fits most with Outlook Sync was the new Kopano, it's more flexible. You can use the web app or desktop app too. Guest • Jan 2017 • 1 agrees and 2 disagrees
- OpenSource, better to maintain, "not Microsoft" Guest • Jan 2017 • 1 agrees and 2 disagrees
Freemium Open Source Mac Windows Linux Web Android ... iPhone Android Tablet Windows Phone iPad Self-Hosted Microsoft Office Outlook S/MIME Software as a Service (SaaS)
CalDAV File sharing Email Server Mobile Device Management ... On-premises software POP3 Support Real time collaboration Shared calendars Add a feature

27 Like
hMail Server

hMailServer is a free e-mail server for Microsoft Windows. Its used by Internet service providers, companies, governments, schools and enthusiasts in all parts of the...

Free Open Source Windows
Convert images to PDF Support for IMAP Email Server POP3 Support ... SMTP SMTP integration Add a feature

25 Like
Zentyal

Zentyal is a native Microsoft Active Directory® implementation on Linux incorporating all the network services required in a small and medium business environment:...
- They do not share any common functionality. Zentyal is an Active Directory substitute, Microsoft Exchange is a groupware E-Mail (enterprise grade) server. Guest • Jan 2020 • 0 agrees and 1 disagrees
- Not an Exchange alternative at all. Does basic AD but that is about it. It is more of a gateway server. Guest • Sep 2019 • 2 agrees and 1 disagrees
- No Exchange alternative and no support for MS Outlook Client Guest • Mar 2018 • 12 agrees and 3 disagrees
Free Open Source Linux
File sharing Gateway Email Server Remote desktop ... Email Server Add a feature

54 Like
mailcow: dockerized

mailcow is a mail server suite based on Dovecot, Postfix, SOGo, Rspamd and other open source software, that provides a modern Web UI for administration.

Free Open Source Linux
Email Server ActiveSync Modular System Self hosted mail ... Support for Docker Email Server Add a feature

31 Like
Kolab Community

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

Freemium Open Source Linux Web Self-Hosted
CalDAV CardDAV Real time collaboration Support for WebDAV Add a feature

38 Like
SOGo

SOGo is groupware server with a focus on scalability and open standards. SOGo provides a rich AJAX-based Web interface and supports multiple native clients through...

Freemium $ $ $ Open Source Linux Web Thunderbird Cloudron
CalDAV CardDAV Support for Multiple Users Scheduling Add a feature

29 Like
iRedMail

A fully fledged, free email server solution, an open source project (GPL v2). Use official binary packages from Linux/BSD distributions, with both i386 and x86_64...

Freemium Open Source Linux BSD Self-Hosted
Email Server Add a feature

20 Like
Zimbra Collaboration Suite

Zimbra Collaboration is an open, secure collaboration tool for email, calendaring, tasks and more. With the most innovative web application available today, Zimbra...

Freemium Open Source Linux Web Self-Hosted
Active Directory integration ActiveSync Email Server Real time collaboration ... Team Collaboration Add a feature

29 Like
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Kolab Now

Kolab Now provides a suite of intuitive apps in a user friendly environment to make your day to day online comms easier, smarter and most importantly; secure.
- With Microsoft no longer supporting our existing setup, this was a great alternative. Guest • Sep 2015 • 2 agrees and 0 disagrees
Commercial $ $ $ Open Source Web Software as a Service (SaaS) DAVdroid
CalDAV CardDAV Cloud Storage Email Server ... Notetaking Real time collaboration Security & Privacy Add a feature

41 Like
Citadel

Is a collaboration suite (messaging and groupware). It is designed to run on open source operating systems such as Linux or BSD. In order to modernize the Citadel...

Free Open Source Linux Web
Chat Real time collaboration Add a feature

6 Like