Top 12 Open-Source Alternatives to Microsoft Exchange Server

Product categories

Anti-Spam Calendar Cyber Security Email Email Clients Email Delivery Email Management Email Service Provider Enterprise Communication MTA SMTP Server Self-hosted Email

Summary

The top open-source alternatives to Microsoft Exchange Server are iRedMail, mailcow, and Roundcube. One of the criteria for ordering this list is the number of mentions that products have on reliable external sources. You can suggest additional sources through the form here.

iRedMail Landing Page
1

iRedMail

A fully fledged, free email server solution, an open source project (GPL v2).
Pricing:
- Open Source
#Email #SMTP Server #Self-hosted Email 2 social mentions
mailcow Landing Page
2

mailcow

An open source mailserver suite.
Pricing:
- Open Source
#Email #Self-hosted Email #Email Service Provider 82 social mentions
Roundcube Landing Page
3

Roundcube

Web-based IMAP email client
Pricing:
- Open Source
#Email #SMTP Server #Email Clients 16 social mentions
SOGo Landing Page
4

SOGo

SOGo is groupware server with a focus on scalability and open standards.
Pricing:
- Open Source
#Email #Email Clients #Self-hosted Email 1 social mentions
Mail-in-a-box Landing Page
5

Mail-in-a-box

Mail-in-a-Box provides webmail and an IMAP/SMTP server for use with mobile devices and desktop mail software and also includes contacts and calendar synchronization.
Pricing:
- Open Source
#Email #Self-hosted Email #Email Service Provider 115 social mentions
Exim Landing Page
6

Exim

Exim is a message transfer agent (MTA) developed at the University of Cambridge for use on Unix systems connected to the Internet.
Pricing:
- Open Source
#SMTP Server #Email #MTA
Dovecot Landing Page
7

Dovecot

Dovecot is an open source IMAP and POP3 email server for Linux/UNIX-like systems, written with...
Pricing:
- Open Source
#Email #SMTP Server #Self-hosted Email
Rainloop Landing Page
8

Rainloop

RainLoop is a web based email client.
Pricing:
- Open Source
#Email #Email Clients #Email Management
OpenSMTPD Landing Page
9

OpenSMTPD

OpenSMTPD is a FREE implementation of the server-side SMTP protocol as defined by RFC 5321, with...
Pricing:
- Open Source
#SMTP Server #Email #MTA 2 social mentions
Mailspring Landing Page
10

Mailspring

Mailspring is a mail client for Mac, Windows and Linux.
Pricing:
- Open Source
#Email #Email Clients #Calendar 25 social mentions
Squirrelmail Landing Page
11

Squirrelmail

SquirrelMail is a standards-based webmail package written in PHP.
Pricing:
- Open Source
#Self-hosted Email #Enterprise Communication #Email 3 social mentions
SpamAssassin Landing Page
12

SpamAssassin

Use this program to "Unspam" your mailbox(es).
Pricing:
- Open Source
#Email Security #Email #Cyber Security 4 social mentions