Roundcube is an open source web-based email client written in PHP. It provides users with a full-featured email interface, including an address book, calendar, task list, file manager, and much more. It supports IMAP and POP3 protocols, and also features an extensive plugin system for customizing the application. It is a modern, user-friendly and intuitive interface, highly configurable and very secure. Roundcube is an ideal solution for companies and organizations that need an easy-to-use, secure and feature-rich email client.
PHP-based and more customizable than roundcube, more modern ui