Top 11 Open-Source Alternatives to Kopano

The top open-source alternatives to Kopano are iRedMail, SOGo, and mailcow. 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
SOGo Landing Page
2

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
3

mailcow

An open source mailserver suite.
Pricing:
- Open Source
#Email #Self-hosted Email #Email Service Provider 82 social mentions
Roundcube Landing Page
4

Roundcube

Web-based IMAP email client
Pricing:
- Open Source
#Email #SMTP Server #Email Clients 16 social mentions
Dovecot Landing Page
5

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
Nextcloud Calendar Landing Page
6

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
Mailpile Landing Page
7

Mailpile

Mailpile is a modern, fast web-mail client with user-friendly encryption and privacy features.
Pricing:
- Open Source
#Email #Email Clients #Email Management
Rainloop Landing Page
8

Rainloop

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

Nextcloud

With Nextcloud enterprises host their own secure cloud solution for storage, collaboration & communication from any device, anywhere.
Pricing:
- Open Source
#Cloud Storage #File Sharing #Encrypted Cloud Storage 283 social mentions
Radicale Landing Page
10

Radicale

The Radicale Project is a complete CalDAV (calendar) and CardDAV (contact) server solution.
Pricing:
- Open Source
#Email #Email Clients #Network & Admin 15 social mentions
WikiSuite Landing Page
11

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