NOCC is a simple and fast Webmail client which can handle POP3 and IMAP mailboxes and sends email via SMTP. It is written with PHP, has low requirements (no database, frames). Features multi-language support, MIME attachments, displays HTML messages.
The installation guide comes with the source code:
https://sourceforge.net/p/nocc/code/HEAD/tree/trunk/webmail/docs/INSTALL
If you encounter problems or bugs you can always try the current HEAD...
RainLoop Webmail is a modern, fast, and lightweight web-based email client. It supports IMAP and SMTP protocols, allowing users to access and manage their email accounts through a web interface. RainLoop offers features like multi-account support, a responsive UI, and integration with popular email providers. It is self-hosted, giving users control over their email data.
Modest system requirements, decent performance, simple installation and upgrade, no database required - all these make RainLoop Webmail a perfect choice for your email solution.
Hastymail is a fast, secure, rfc-compliant, cross-platform IMAP/SMTP client application written in PHP providing a clean web interface for sending and reading E-mail.
This version of Hastymail is no longer being developed. We are now working on a new version, Hastymail 3, AKA, "Cypht".
http://cypht.org
W3MAIL - fast and small webmail client written in PHP5. It provides easy
webmail access to IMAP accounts and has very few requirements to install. Features multi-language support, simple contacts manager, MIME attachments, displays HTML messages.
Phosta is yet another web-mail system, written in PHP, that wants to be fast, lightweight, simple to configure and fully customizable in about all of it's parts.
YANOCC is a simple and fast webmail client which can handle POP3, SMTP, and IMAP servers. YANOCC is based on NOCC's code and is written with PHP4. It features multi-language support, MIME attachments, displays HTML messages, address book, folder support.