Electronic mail is a method of exchanging messages ("mail") between people using electronic devices. Invented by Ray Tomlinson, email first entered limited use in the 1960s and by the mid-1970s had taken the form now recognized as email. Email operates across computer networks, which today is primarily the Internet. Some early email systems required the author and the recipient to both be online at the same time, in common with instant messaging. Today's email systems are based on a store-and-forward model. Email servers accept, forward, deliver, and store messages. Neither the users nor their computers are required to be online simultaneously; they need to connect only briefly, typically to a mail server or a webmail interface for as long as it takes to send or receive messages or to download it.
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.
Pine is a freeware, text-based email client which was developed at the University of Washington. The first version was written in 1989, and announced to the public in March 1992. Source code was available for only the Unix version under a license written by the University of Washington. Pine is no longer under development, and has been replaced by the Alpine client, which is available under the Apache License.
An email client, email reader or more formally mail user agent (MUA) is a computer program used to access and manage a user's email.
Sylpheed is an open-source e-mail client and news client licensed under the GPL. It provides easy configuration and an abundance of features. It stores mail in the MH Message Handling System. Sylpheed runs on Unix-like systems such as Linux or BSD, and it is also usable on Windows. It uses GTK+.
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.
Pegasus Mail is a proprietary email client developed by David Harris. It was originally released in 1990 for internal and external mail on NetWare networks with MS-DOS and later Apple Macintosh clients. It was subsequently ported to Microsoft Windows, which is now the only platform actively supported. Previously freeware, Pegasus Mail is now donationware.
Kontact is a personal information manager and groupware software suite developed by KDE. It supports calendars, contacts, notes, to-do lists, news, and email. It offers a number of inter-changeable graphical UIs all built on top of a common core.
The following tables compare general and technical features of a number of notable email client programs.
Scalix is an e-mail and groupware server that runs on Linux, licensed under the Scalix Public License (SPL).
Mulberry is an open-source email client marketed by Cyrusoft from approximately 1995 to 2005. On October 1, 2005, Cyrusoft International, Inc./ISAMET, declared Chapter 7 bankruptcy and went out of business. In August 2006, rights to the source code were acquired by Cyrus Daboo, the original author.
Conversation threading is a feature used by many email clients, bulletin boards, newsgroups, and Internet forums in which the software aids the user by visually grouping messages with their replies. These groups are called a conversation, topic thread, or simply a thread. A discussion forum, e-mail client or news client is said to have a "conversation view", "threaded topics" or a "threaded mode" if messages can be grouped in this manner.
Claws Mail is a free and open-source, GTK+-based email and news client. It offers easy configuration and an abundance of features. It stores mail in the MH mailbox format and also the Mbox mailbox format via a plugin. Claws Mail runs on both Windows and Unix-like systems such as Linux, BSD, and Solaris.
Zarafa was an open-source groupware application that originated in the city of Delft in the Netherlands. The company that developed Zarafa, previously known as Connectux, is also called Zarafa. The Zarafa groupware provided email storage on the server side and offered its own Ajax-based mail client called WebAccess and a HTML5-based, WebApp. Advanced features were available in commercially supported versions. Zarafa has been superseded by Kopano.
Trojitá is a free software IMAP and SMTP email client developed using the Qt C++ library. The design goals of the maintainers are to develop a fast e-mail client which respects open standards, is cross-platform and uses the available resources very efficiently.
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.
Kopano is an open-source groupware application suite originally based on Zarafa. The initial version of Kopano Core (KC) was forked from the then-current release of the Zarafa Collaboration Platform, and superseded ZCP in terms of lineage as ZCP switched to maintenance mode with patches flowing from KC. Kopano WebApp similarly descended from Zarafa WebApp. Since October 2017, Kopano Core is also known more specifically as Kopano Groupware Core, since Kopano B.V. developed more products that were not directly requiring groupware components.
Hiri was a business focused desktop e-mail client for sending and receiving e-mails, managing calendars, contacts, and tasks. It was developed as an alternative to existing e-mail clients and calendar applications such as Microsoft Outlook and Mozilla Thunderbird. Development on Hiri started in late 2012 in Dublin, Ireland. Although Hiri was developed actively with many releases in primarily 2017 and the first half of 2018, there have been no new releases and no active development anymore since August 2018. Also, Hiri Suggestions, a dedicated subdomain for acquiring new ideas for development, has not received replies from the development since last year.
