Open Source ChromeOS Email Clients

SquirrelMail is a PHP-based Web email client. It includes built-in pure PHP support for IMAP and SMTP, and renders all pages in pure HTML 4.0 for maximum compatibility across browsers. It has strong MIME support and a flexible plugin system.

Trojitá, a Qt IMAP e-mail client

Proton Web Clients is a monorepo hosting the web applications for Proton’s suite of privacy-focused services, including the core Proton Mail webmail interface and related web apps like Proton Calendar, Proton Drive, Proton Account, Proton VPN, Proton Pass, and other connected tools. It consolidates all web client code, shared modules, dependencies, and development tooling into a single repository, enabling unified maintenance, consistency of design patterns, and efficient evolution of Proton’s online interfaces. These web clients run entirely in the browser, letting users securely interact with their email, calendars, files, and other services without needing native software installed, and benefiting from end-to-end encryption where applicable. The monorepo includes application logic, UI components, build scripts, and testing infrastructure for reliable deployments and streamlined continuous integration.

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 version: https://sourceforge.net/p/nocc/code/HEAD/tarball?path= Questions, bug reports or support requests are very welcome: https://sourceforge.net/p/nocc/_list/tickets Alternative source code repository: https://github.com/oheil/NOCC

PHP app to access Gmail/Googlemail/Gmail-for-Your-Domain accounts on wireless devices. Convenient alternative access method to your email account on the move, gmail-mobile incorporates as many Gmail features as possible within limits of a mobile device.

Columba is an email client written in Java, featuring a user-friendly graphical interface with wizards and internalionalization support. Its a powerful mail management tool with features to enhance your productivity and communication.

MultiMail is an offline mail packet reader for Unix and other systems. It currently supports the Blue Wave, QWK, OMEN, OPX and SOUP formats. It has a full screen, color user interface, built with the curses library.

EGroupware has moved to Github, please find all our downloads there: https://github.com/EGroupware/egroupware/releases EGroupware is a multi-user, web-based groupware suite. Currently available modules include: email, addressbook, calendar, infolog (notes, to-do's, phone calls), content management, wiki, project management, tracker, timesheet, knowledge base, CalDAV/CardDAV

JMail is a mail client written in Java. It handles attached files, HTML mails, filters and other stuff... It can be used with a LDAP directory.

AfterLogic WebMail Lite PHP is a free AJAX webmail application. Users can receive, view, manage, compose, and send email through web interface (IMAP and SMTP supported). Source code included.

SaltOS is a Business Management solution 100% Cloud Computing. It integrates features like CRM (Customer Relation Management) and ERP (Enterprise Resource Planning). Moreover is it licensed as 100% free software GPL-3.0.

MH-E is the Emacs interface to the MH mail system. It offers all the functionality of MH, the visual orientation and simplicity of use of a GUI, and full integration with Emacs, including thorough configuration and online help. Since MH-E 8.6 was released in 2016, its development migrated to the Emacs repository. Thus, if you install an Emacs package, or check out and compile the Emacs source, then you will be running the latest version of MH-E. Consequently, we will retire this site once all of the tickets are resolved. Therefore, please help us out and submit new tickets with M-x report-emacs-bug. MH-E is now only supported in the version of GNU Emacs in which it appears. It is no longer supported in XEmacs. It is compatible with MH versions 6.8.4 and higher, all versions of nmh, and GNU mailutils 1.0 and higher.

libgmailer for PHP consists of 2 parts: {GMailer (libgmailer)} a PHP class/library for you to access GMail with PHP with ease. {gmail-lite} a plain HTML only interface of GMail, accessible by any browser on Earth.

Special Folders Plugin is a plugin for the popular webmail Roundcube. This plugin lets the admin define new special folders, which will be displayed at top of folders lists. Admin can directly choose the real mail folder, a name for it and the icon.

jwSMTP, Send email programmatically (C++ code/lib). Linux, BSD, Windows etc. Attachments, Multiple recipients, Cc/Bcc recipients supported. MX lookup or send to an SMTP server direct. LOGIN and PLAIN authentication now supported. Html or plain text forma

Mailcrypt is an Emacs Lisp package which provides a simple interface to public key cryptography with PGP [and now GnuPG!]. Mailcrypt makes strong cryptography a fully integrated part of your normal mail and news handling environment

Null Webmail is a simple yet powerful POP3/SMTP Webmail CGI written in C. It's small, fast, complete, and a breeze to install and use.

Browsing your mail on mail server, And deleting mails without downloading.

This plugin will add to the AJAX Webmail RoundCube the ability to tag mails like it is done in Thunderbird. He will follow the same semantic as Thunderbird to manage tag, so tags set using this plugins will be seen in Thunderbird and vice-versa.

Engroup is the web enterprise groupware promotes various collaboration methods plus adding company business management modules. Features are included: CRM, HRM, Document Management, Project Management, Chat, Wiki, Forum, News, Todo.

jwma (java webmail app) uses jakarta mail (formerly javamail) to provide access to an imap email store. Multiple users can authenticate, read, send and manipulate email storage and persist a list of contacts, email identities and their own individual preferences. It works with email stored in mbox or maildir format or stored in a derby database; it has been tested with dovecot.james and exim4. See http://jwma.sourceforge.net/ for further details.

6XMailer is a PHP POP3 mail reader with support for HTML mail, MIME attachments, embedded mail content, multilingual ready, and themes. It has an address book and centralized configuration file.

Webmail client for call center agents. Designed to efficiently manage and report on a large number of emails to a small number of email addresses. Specifically designed with webforms in mind where one email address may receive over 1000 emails per day.

A GUI-based email application capable of recording, compressing and sending voice messages.

"Archive This" is an add-on for the Thunderbird email client that provides shortcuts for filing messages into folders rapidly and efficiently.