In computing, the Post Office Protocol (POP) is an application-layer Internet standard protocol used by e-mail clients to retrieve e-mail from a mail server. Today, POP version 3 (POP3) is the most commonly used version. Together with IMAP, it is one of the most common protocols for email retrieval.
An email client, email reader or, more formally, message user agent (MUA) or mail user agent is a computer program used to access and manage a user's email.
GNOME Evolution is the official personal information manager for GNOME. It has been an official part of GNOME since Evolution 2.0 was included with the GNOME 2.8 release in September 2004. It combines e-mail, address book, calendar, task list and note-taking features. Its user interface and functionality is similar to Microsoft Outlook. Evolution is free software licensed under the terms of the GNU Lesser General Public License (LGPL).
gedit is a text editor designed for the GNOME desktop environment. It was GNOME's default text editor and part of the GNOME Core Applications until GNOME version 42 in March 2022, which changed the default text editor to GNOME Text Editor. Designed as a general-purpose text editor, gedit emphasizes simplicity and ease of use, with a clean and simple GUI, according to the philosophy of the GNOME project. It includes tools for editing source code and structured text such as markup languages.
Damn Small Linux (DSL) is a computer operating system for the x86 family of personal computers. It is free and open-source software under the terms of the GNU GPL and other free and open-source licenses. It was designed to run graphical user interface applications on older PC hardware, for example, machines with 486 and early Pentium microprocessors and very little random-access memory (RAM). DSL is a live CD with a size of 50 megabytes (MB). What originally began as an experiment to see how much software could fit in 50 MB eventually became a full Linux distribution. It can be installed on storage media with small capacities, like bootable business cards, USB flash drives, various memory cards, and Zip drives.
Mutt is a text-based email client for Unix-like systems. It was originally written by Michael Elkins in 1995 and released under the GNU General Public License version 2 or any later version.
SquirrelMail is a project that aims to provide both a web-based email client and a proxy server for the IMAP protocol.
The following tables compare general and technical features of notable non-web-based email client programs.
Kolab is a free and open source groupware suite. It consists of the Kolab server and a wide variety of Kolab clients, including KDE PIM-Suite Kontact, Roundcube web frontend, Mozilla Thunderbird and Mozilla Lightning with SyncKolab extension and Microsoft Outlook with proprietary Kolab-Connector PlugIns.
Claws Mail is a free and open-source, C/GTK-based e-mail client, which is both lightweight and highly configurable. Claws Mail runs on both Windows and Unix-like systems such as Linux, BSD, and Solaris. It stores mail in the MH mailbox format. Plugins allow to read HTML mail, but there is none to compose HTML messages.
GNUMail is a free and open-source, cross-platform e-mail client based on GNUstep or Cocoa. It is the official mail client of GNUstep and is also used in Étoilé. It was inspired by NeXTMail, the predecessor of Apple Mail. GNUMail is based on the mail handling framework Pantomime. GNUMail demonstrated that it is possible to develop cross platform programs for GNUstep and Cocoa.
Mahogany is an open source cross-platform email and news client. It is available for X11/Unix and MS Win32 platforms, supporting a wide range of protocols and standards, including SMTP, POP3, IMAP, NNTP and full MIME support. The current official release version is 0.67.
Wayland is a communication protocol that specifies the communication between a display server and its clients, as well as a C library implementation of that protocol. A display server using the Wayland protocol is called a Wayland compositor, because it additionally performs the task of a compositing window manager.
Ayttm is a multi-protocol instant messaging client. It is the heir of the EveryBuddy project.
OpenConnect is a free and open-source cross-platform multi-protocol virtual private network (VPN) client software which implement secure point-to-point connections.
X2Go is open source remote desktop software for Linux that uses a modified NX 3 protocol. X2Go gives remote access to a Linux system's graphical user interface. It can also be used to access Windows systems through a proxy.
Geary is a free and open-source email client written in Vala and based on WebKitGTK. Although since adopted by the GNOME project, it originally was developed by the Yorba Foundation. The purpose of this e-mail client, according to Adam Dingle, Yorba founder, was to bring back users from online webmails to a faster and easier to use desktop application.
