Simple, modern & fast web-based email client.

Modest system requirements, decent performance, simple installation and upgrade, no database required - all these make RainLoop Webmail a perfect choice for your email solution.

• RainLoop Webmail @ GitHub.

Open Source Groupware.
SOGo is a fully supported and trusted groupware server with a focus on scalability and open standards. SOGo is released under the GNU GPL/LGPL v2 and above.
SOGo provides a rich AJAX-based Web interface and supports multiple native clients through the use of standard protocols such as CalDAV, CardDAV and GroupDAV, as well as Microsoft ActiveSync.

complete mail server
SMTP + IMAP + POP3 + Antispam + Antivirus
Web administration + Web email ...on your server in ~5 minutes

Email, collaboration, groupware and content management

Open Source email server software & mobility

Citadel is easy, versatile, and powerful, thanks to its exclusive "rooms" based architecture. No other platform seamlessly combines so many different features using this familiar and consistent metaphor.

Free, modern & fast web-based email client

A modern, fast web-mail client with user-friendly encryption and privacy features. 100% Free and Open Source software