What is SquirrelMail?

SquirrelMail is a standards-based webmail package written in PHP. It includes built-in pure PHP support for the IMAP and SMTP protocols, and all pages render in pure HTML 4.0 (with no JavaScript? required) for maximum compatibility across browsers. It has very few requirements and is very easy to configure and install. SquirrelMail has all the functionality you would want from an email client, including strong MIME support, address books, and folder manipulation. Link to SquirrelMail-Website:  http://www.squirrelmail.org

Stability

SquirrelMail is stable enough to use in a production system. It is, in fact, already used in several production systems around the world, handling thousands of users per system. There might be some bugs - no project is perfect - but they are most likely minimal. We test pretty thoroughly before releasing a version marked as "stable". More about Scalability:  http://www.squirrelmail.org/about/scalability.php

License

SquirrelMail is licensed under the GNU General Public License (GPL), so there are no license fees to worry about. More about the license:  http://www.squirrelmail.org/about/license.php