List of freely available Mail clients
| Name | Lang | Comments |
| Adora | Tcl/Tk | Supports MBOX and POP3. No more developed. |
| Aethera | C++ (KDE) | Based on the Magellan source. Should be KDE's Outlook/Evolution. |
| Aileron | C (c-client, WINGs) | The philosophy behind Aeleron is to be as similar to NeXTSTEP's Mail.app as possible, right down to the menu keybindings. |
| Althea | C (GTK+) | IMAP only; very simple. |
| Animail | Python | |
| Archimedes | C (GTK+) | Would be XFMail successor. |
| Arrow | C++ (JX) | Displays each mailbox and message in a separate window. MBOX and POP only. |
| Balsa | C (Gnome) | Supports mbox, maildir, mh, POP3 and IMAP. Uses libmutt as backend. Supports different encodings. |
| CMC | Perl/GTK+ | |
| Cronos II | C (Gnome) | Uses its very own database storage format. |
| CSCMail | Perl/GTK+ | Supports mbox, maildir and POP3, can use database supported by Perl DBI interface as the backend. |
| elm | elm is one of the most common mail readers for unix. | |
| Eucalyptus | C (Gnome) | Previously available for the Amiga, it is being totally rewritten for Linux using Gnome/GTK+. Now development seems to be stopped. |
| Evolution | C (Gnome) | Should be Gnome's Outlook. Supports VFolders. Supports different encodings. |
| Exmh | Tcl/Tk | Exmh is an X user interface for MH mail. |
| Ezimail | C (Curses) | Ezimail is a port of the Carnegie Mellon AMS client ezmail modified to use IMAP. It is a text-based client and supports strong authentication. |
| gmail | C (Gnome) | Uses an sql (Mysql) vfolder-based storage. |
| GNUMail | Objective-C (GNUstep) | Supports SMTP, POP3, IMAP, mbox. |
| Grin | C (Gnome) | More news than mail client. |
| gtkmail | C++ (gtk--) | |
| Ishmail | C++ (Motif) | Until recently, it was a commercial flagship product developed by HAL Computer Systems (then H&L Software). Now it's GPLed. Messages are opened in separate windows. Supports different encodings. |
| Kiltdown | C++ (Qt) | Currently supports only POP3 and mail spool files. |
| KMail | C++ (KDE) | |
| Magellan | C++ (KDE) | |
| Mahogany | C++ (c-client, wxWidgets) | It is very cofigurable, supports mbox, mh, pop3 and imap, has filters, supports multiple encodings, has multiple identities, can be scripted and extended thanks to a builtin Python interpreter and has PalmOS connectivity. |
| mailtool ? | ||
| ML | C (c-client, Motif) | not updated from 1998. |
| MMC | C (Gnome) | |
| MMR | C++ | MMR is a very simple mailer written as an alternative to PINE. It's not very fancy, but it handles message threading and MIME attachments. |
| Mozilla | C++ | |
| Mulberry | C++ (JX) | Displays each mailbox and message in a separate window. Supports MBOX, POP3 and IMAP. Commercial with trial version. |
| Mutt | C | Small but very powerful text-based MIME mail client. It is highly configurable. |
| Netscape | ||
| nmh | nmh (new MH) is a powerful electronic mail handling system. It was originally based on version 6.8.3 of the MH message system. | |
| Ntool | C (GTK+) | |
| Pine | C (c-client) | |
| PMail | Python (Gnome) | Supports IMAP4, POP3, and MH folders. |
| Postilion | C, Tcl/Tk | Postilion is a mail user agent based upon the popular TkRat program. The main changes to TkRat are in the user interface portion. It looks like NeXT Mail.app and it's best when compiled and run with TkStep8.0.4 instead of the regular Tk. It REQUIRES Tcl/Tk 8.0p2 and because of that it does not support multiple encodings which were introduced only in Tcl/Tk 8.1. |
| Post Office | C++ (FLTK) | |
| Privtool | C (XView, Motif or GTK+) | Privtool ("Privacy Tool") is intended to be a PGP-aware replacement for the standard Sun Workstation mailtool program, with a similar user interface and automagick support for PGP-signing and GP-encryption. |
| Pronto! | Perl/GTK+ | Supports mbox, maildir and POP3, can use database supported by Perl DBI interface as the backend. Supports Vfolders. Pronto is continuation of CSCMail after CSCMail moved to C. |
| Pygmy | Python (Gnome) | Only supports the Unix mailbox format. |
| Pyne | Python (pygtk) | Supports SMTP, POP3, IMAP4, MH, Unix mailbox, NNTP. |
| rzMail | Python (wxPython) | |
| SQmaiL | Python (Gnome) | Uses mySQL for message storage. |
| Spruce | C (GTK+) | Supports mbox, POP3 and IMAP. |
| Sylpheed | C (GTK+) | Lightweight, and fast e-mail client. Supports MBOX, MH, POP3 and IMAP. Supports multiple encodings using jconv. |
| TkRat | C, Tcl/Tk | It is mainly written in C but the user interface is done in tcl/tk. Supports MIME, multiple encodings, Virtual folders, PGP support, unix mail files, MH folders, POP3 and IMAP. |
| TradeClient | C (c-client, GTK+) | Uses Mahogany patch for c-client. TradeClient is an LGPL'd subset of Bynari's TradeXCH client. It has support for a personal calendar, MBOX, POP3, IMAP. |
| Ultimate Mail Tool | C++ | Supports POP3, SMIME. Old client, but now development resumed. |
| (X)Emacs/VM | VM is a mail reader written in Emacs LISP for GNU Emacs and XEmacs. It supports local spool files, POP3 and IMAP, vfolders. | |
| (X)Emacs/Gnus | ||
| (X)Emacs/Mew | ||
| XCmail | C++ (Xclasses) | Supports mbox and POP3, has helpers, filters, PGP support. |
| XFMail | C (XForms) | Supports MBOX, MH, POP3, IMAP, multiple encodings. |
| xPine | C (c-client, XClass95) | xPine provides an intuitive, high quality GUI to Pine. |
| YPMail.app | C (c-client, WINGs) | Supports local mailboxes. |