Open Source Linux Email Clients

Free Windows Mbox Viewer. Gain access to mbox archives, single eml or single Outlook messages. View attachments and export single mails in eml format. Access large mbox files such as Google Takeout or Mozilla Thunderbird Archives. Development of mbox viewer continues now at github: https://github.com/eneam/mboxviewer **NOTE**: Windows Defender may sometimes report incorrectly that mbox-viewer contains malware. Please report the case to the development. Development will ask Windows Security to update Windows Defender rules to resolve the issue. Last time the incorrect detection was corrected by Microsoft Security within few hours. User will need to run Windows Update to install the latest updated detection rules.

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.

Tutanota is an open source email client focused on security and privacy. It is built with end-to-end encryption and 2FA, so you can be assured of utmost email security. Tutanota is always encrypted, so whether you’re using their secure webmail client, mobile apps or desktop clients, you can be sure to communicate securely.

Mailspring is a fast and lean mail client that’s a new version of Nylas Mail. It’s maintained by one of Nylas Mail’s original authors, with plenty of great features and enhancements such as a new C++ sync engine that allows it to use 50% less RAM. Heavy dependencies have also been removed and the package manager rewritten for even greater speed. Written in TypeScript with Electron and React, it is cross-platform (macOS, Windows and Linux) and designed to be easy to extend.

A PHP email creation and transport class featuring file attachments, SMTP servers, CCs, BCCs, HTML messages, word wrap, and more. Sends email via sendmail, PHP mail(), QMail, or with SMTP. PHPMailer is used by many popular PHP development frameworks and is one of the most popular email-generating and sending libraries in the world. This project is defunct here on sourceforge – it's now maintained on Github at https://github.com/PHPMailer/PHPMailer. Documentation is available at https://github.com/PHPMailer/PHPMailer/wiki

Proton Mail Bridge is a desktop application that runs in the background on Windows, macOS, and Linux to enable users to access their Proton Mail encrypted email accounts with traditional email clients like Outlook, Thunderbird, Apple Mail, and others via local IMAP/SMTP servers. Because standard IMAP cannot natively decrypt end-to-end encrypted messages, Bridge acts as a translator that downloads encrypted mail, decrypts it locally, and serves it to your preferred mail client over a local server, while encrypting outgoing messages before they’re sent to Proton’s servers. It provides a seamless integration layer for users who need offline support, familiar local client workflows, or tighter integration with desktop tools while preserving Proton’s zero-access encryption model. The Bridge app continues running even when its GUI is closed so that mail clients can remain connected and synchronized, and it supports automatic startup and robust credential handling via secure storage.

Trojitá, a Qt IMAP e-mail client

GoldBug is a decentralized & secure communication suite that offers an integrated e-mail client, an instant messenger & a file transfer. Also included is an URL-RSS-DB & a p2p web search. Current vers. w/ McEliece Algorithm. GoldBug has been 2013 - 2023 ten years just another Graphical User Interface of the Spot-On Encryption Suite. Main GUI features: Minimal & colorful Interface with Tabs in the East. Microsoft & Qt MinGW deprecated Win32 & for Compiling: ● https://sourceforge.net/p/goldbug/wiki/compiling As Spot-On implemented the minimal GB-concept & Nuvola Icons, GoldBug has now been fully integrated into Spot-On Win64: Just choose Tabs at East & Mini-View in Options - w/ Nuvola Icons of course! Voilá! & Many Thanks, Pro-Files can be found archived at ● current source: https://github.com/textbrowser/spot-on ● EN Manual: https://www.amazon.com/dp/3749435065 ● DE: https://compendio.github.io/goldbug-manual-de/ ● Study: https://www.amazon.com/asin/dp/3750408971

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

Claws Mail is a GTK+ based, lightweight, and fast e-mail client and newsreader. Supports POP3, APOP, IMAP, SMTP, SMTP AUTH, NNTP, LDAP, multiple accounts, spell-checking, addressbook, SSL, GPG, filtering, i18n, & more. It is further extended by plugins.

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.

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

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.

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.

IGSuite is a web-based Integrated Groupware Suite oriented to be a CRM solution. In the Suite you can find: IGWebMail, IGCalendar, IGContacts, IGArchive, IGWiki, IGTodo, IGChat, Projects, IGFax an HylaFax client, IGFileManager, IGMsg and many other.

Add support for making Gmail the default mail application for the GNOME desktop. "Gmail" will be a choice for Mail Reader in the Preferred Applications dialog. "Mailto" links, "Send Link", etc., will be handled by Gmail.

exmh is a user interface to the MH (a.k.a. nmh) email system. It is extensible and its users have exploited this to integrate PGP, Glimpse, ispell, faces/picons, MIME, and much more.

This project builds on top of the (and adds additional) scripts included with msmtp (a command-line send only email client) in order for it to act as a queueing Mail Transport Agent (by acting as the sendmail command; it also offer an minimalist SMTP server mode) with some additional features like verify-before-send (which requires you to confirm that you really do want to send email, after a required delay (cooling off period)) for those who need to think twice about the wisdom of what they send, or who tend to notice their grammar spelling errors after the fact.

To provide Polish translation of all Mozilla.org products...

Tiny application based on readpst and dbxconv that provides a convenient GUI to convert Outlook and Outlook Express files into open standards. The program converts Outlook Express 5/6 .DBX to .EML and Outlook 2003/2007/2010 .PST to MBOX. The program runs only on Linux machines and doesn't need any Microsoft software!

Is an ASP.NET webmail application written in C#. It uses a POP3 or IMAP servers as the mailstore and sends mail through a SMTP server. You can compose HTML messages, search your inbox, read complex mime messages and much more. .NET and Mono compatible.

Note! Code and issues are maintained at https://github.com/sba1/simplemail. SimpleMail is a simple to use but powerful mail client. It supports the SMTP, POP3 and IMAP (in a simple form) protocols. Furthermore, among much other features, it is capable of showing HTML mails and can identify spam mails by using a Bayesian filter.

G4J is a set of API that communicate to GMail. Use this API to login, retrive/search/browse message, download attachment and do others action on GMail account! An email application (Gmailer for java) is included to demonstrate the usage of the API.

Strike the 'T' key to sort messages by thread, strike the 'U' key to sort unthreaded again, just like the 'G' key switches to Grouped By Sort view.

Ghost In The Mail is a very basic mail client for Linux, written in C, for GTK. It supports attached files. The user can specify the SMTP server, the sender's e-mail, and the name.