Top 12 Open-Source Alternatives to Kolab Community

The top open-source alternatives to Kolab Community are Roundcube, iRedMail, and SOGo. 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.

Roundcube Landing Page
1

Roundcube

Web-based IMAP email client
Pricing:
- Open Source
#Email #SMTP Server #Email Clients 16 social mentions
iRedMail Landing Page
2

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
SOGo Landing Page
3

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
mailcow Landing Page
4

mailcow

An open source mailserver suite.
Pricing:
- Open Source
#Email #Self-hosted Email #Email Service Provider 82 social mentions
Rainloop Landing Page
5

Rainloop

RainLoop is a web based email client.
Pricing:
- Open Source
#Email #Email Clients #Email Management
Mailpile Landing Page
6

Mailpile

Mailpile is a modern, fast web-mail client with user-friendly encryption and privacy features.
Pricing:
- Open Source
#Email #Email Clients #Email Management
Squirrelmail Landing Page
7

Squirrelmail

SquirrelMail is a standards-based webmail package written in PHP.
Pricing:
- Open Source
#Self-hosted Email #Enterprise Communication #Email 3 social mentions
Cypht Landing Page
8

Cypht

All your E-mail, from all your accounts, in one place. Cypht is like a news reader, but for E-mail.
Pricing:
- Open Source
#Email #Email Clients #Email Management 4 social mentions
Simple Calendar Landing Page
9

Simple Calendar

A simple calendar with events (optional recurring and reminders), week numbers and a customizable...
Pricing:
- Open Source
#Calendar #Appointments and Scheduling #Email 99 social mentions
Nextcloud Calendar Landing Page
10

Nextcloud Calendar

The Calendar app is a user interface for Nextcloud's CalDAV server.
Pricing:
- Open Source
#Calendar #Appointments and Scheduling #Email 4 social mentions
Mail-in-a-box Landing Page
11

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
WikiSuite Landing Page
12

WikiSuite

While Wikipedia is the broadest unified body of knowledge, WikiSuite is the most comprehensive and integrated Open Source enterprise solution.
Pricing:
- Open Source
- Free
#Enterprise Content Management #Enterprise Communication #Team Collaboration