BitchX is a free IRC client that has been regarded as the most popular ircII-based IRC client. The initial implementation, written by "Trench" and "HappyCrappy", was a script for the IrcII chat client. It was converted to a program in its own right by panasync. BitchX 1.1 final was released in 2004. It is written in C and is a TUI application utilizing ncurses. GTK+ toolkit support has been dropped. It works on all Unix-like operating systems, and is distributed under a BSD license. It was originally based on ircII-EPIC, and eventually it was merged into the EPIC IRC client. It supports IPv6, multiple servers and SSL, and a subset of UTF-8 with an unofficial patch.
ICQ was a cross-platform instant messaging (IM) and VoIP client. The name ICQ derives from the English phrase "I Seek You". Originally developed by the Israeli company Mirabilis in 1996, the client was bought by AOL in 1998, and then by Mail.Ru Group in 2010.
Instant messaging (IM) technology is a type of synchronous computer-mediated communication involving the immediate (real-time) transmission of messages between two or more parties over the Internet or another computer network. Originally involving simple text message exchanges, modern IM applications and services tend to also feature the exchange of multimedia, emojis, file transfer, VoIP, and video chat capabilities.
ChatZilla is an IRC client that is part of SeaMonkey. It was previously an extension for Mozilla-based browsers such as Firefox, introduced in 2000. It is cross-platform open source software which has been noted for its consistent appearance across platforms, CSS appearance customization and scripting.
Trillian is a proprietary multiprotocol instant messaging application created by Cerulean Studios. It is currently available for Microsoft Windows, macOS, Linux, Android, iOS, BlackBerry OS, and the Web. It can connect to multiple IM services, such as AIM, Bonjour, Facebook Messenger, Google Talk (Hangouts), IRC, XMPP (Jabber), VZ, and Yahoo! Messenger networks; as well as social networking sites, such as Facebook, Foursquare, LinkedIn, and Twitter; and email services, such as POP3 and IMAP.
Pidgin is a free and open-source multi-platform instant messaging client, based on a library named libpurple that has support for many instant messaging protocols, allowing the user to simultaneously log in to various services from a single application, with a single interface for both popular and obsolete protocols, thus avoiding the hassle of having to deal with new software for each device and protocol.
Yahoo! Messenger was an advertisement-supported instant messaging client and associated protocol provided by Yahoo!. Yahoo! Messenger was provided free of charge and could be downloaded and used with a generic "Yahoo ID" which also allowed access to other Yahoo! services, such as Yahoo! Mail. The service also offered VoIP, file transfers, webcam hosting, a text messaging service, and chat rooms in various categories.
Mozilla Thunderbird is a free and open-source email client that also functions as a personal information manager with a calendar and contactbook, as well as an RSS feed reader, chat client (IRC/XMPP/Matrix), and news client. Operated by MZLA Technologies Corporation, a subsidiary of the Mozilla Foundation, Thunderbird is an independent, community-driven project that is managed and overseen by the Thunderbird Council, which is elected by the Thunderbird community. As a cross-platform application, Thunderbird is available for Windows, macOS, FreeBSD, and Linux. The project strategy was originally modeled after that of Mozilla's Firefox, and Thunderbird is an interface built on top of that Web browser.
Kopete is a multi-protocol, free software instant messaging client released as part of the KDE Software Compilation. Although it can run in numerous environments, it was designed for and integrates with the KDE Plasma Workspaces. Kopete was started because ICQ blocked Licq from their network in 2001. According to the original author, Duncan Mac-Vicar Prett, the name comes from the Chilean Spanish word copete, meaning "a drink with your friends". Kopete has been nominated for multiple awards. The designated successor is KDE Telepathy from the KDE RTCC Initiative.
The Invisible Internet Project (I2P) is an anonymous network layer that allows for censorship-resistant, peer-to-peer communication. Anonymous connections are achieved by encrypting the user's traffic, and sending it through a volunteer-run network of roughly 55,000 computers distributed around the world. Given the high number of possible paths the traffic can transit, a third party watching a full connection is unlikely. The software that implements this layer is called an "I2P router", and a computer running I2P is called an "I2P node". I2P is free and open sourced, and is published under multiple licenses.
Google Talk was an instant messaging service that provided both text and voice communication. The instant messaging service was variously referred to colloquially as Gchat, Gtalk, or Gmessage among its users.
Off-the-record Messaging (OTR) is a cryptographic protocol that provides encryption for instant messaging conversations. OTR uses a combination of AES symmetric-key algorithm with 128 bits key length, the Diffie–Hellman key exchange with 1536 bits group size, and the SHA-1 hash function. In addition to authentication and encryption, OTR provides forward secrecy and malleable encryption.
The following tables compare general and technical information between a number of notable IRC client programs which have been discussed in independent, reliable prior published sources.
Empathy was an instant messaging (IM) and voice over IP (VoIP) client which supported text, voice, video, file transfers, and inter-application communication over various IM communication protocols.
WeeChat is a free and open-source Internet Relay Chat client that is designed to be light and fast. It is released under the terms of the GNU GPL-3.0-or-later and has been developed since 2003.
XiRCON is a discontinued freeware IRC client for Microsoft Windows. After TCP/IP was added to Windows, XiRCON was one of the most popular IRC clients on the platform. The XiRCON client was used for a number of fields, such as library helpdesk, genealogy, and US Naval command. Author Mark Hanson ceased development in 1997.
Cryptocat is a discontinued open-source desktop application intended to allow encrypted online chatting available for Windows, OS X, and Linux. It uses end-to-end encryption to secure all communications to other Cryptocat users. Users are given the option of independently verifying their buddies' device lists and are notified when a buddy's device list is modified and all updates are verified through the built-in update downloader.
Phalcon is a PHP web framework based on the model–view–controller (MVC) pattern. Originally released in 2012, it is an open-source framework licensed under the terms of the BSD License.
Keybase is a key directory that maps social media identities to encryption keys in a publicly auditable manner. Additionally it offers an end-to-end encrypted chat and cloud storage system, called Keybase Chat and the Keybase Filesystem respectively. Files placed in the public portion of the filesystem are served from a public endpoint, as well as locally from a filesystem mounted by the Keybase client.
