qTox is a Tox client that follows the Tox design guidelines. It provides an easy to use application that allows you to connect with friends and family without anyone else listening in.

ZNC is an IRC network bouncer or BNC. It can detach the client from the actual IRC server, and also from selected channels. Multiple clients from different locations can connect to a single ZNC account simultaneously and therefore appear under the same nickname on IRC.

LibGadu is library for handling Gadu-Gadu instant messenger protocol. The library is written in C and aims to be operating system and environment independent.

This package provides a C++ library for parsing, formatting, and validating international phone numbers.

GNU Freetalk is a command-line Jabber/XMPP chat client. It notably uses the Readline library to handle input, so it features convenient navigation of text as well as tab-completion of buddy names, commands and English words. It is also scriptable and extensible via Guile.

Nheko want to provide a native desktop app for the Matrix protocol that feels more like a mainstream chat app and less like an IRC client.

Many matrix features are supported, including user registration, rooms, typing notification, emojis, E2E encryption, and voip calls.

Libircclient is a library which implements the client IRC protocol. It is designed to be small, fast, portable and compatible with the RFC standards as well as non-standard but popular features. It can be used for building the IRC clients and bots.

This module implements support for a group of push notification extensions by the Tigase team that allow a client to specify filters to be applied to push notifications. It is a custom extension to XEP-0357: Push Notifications.

Chatty is a chat program for XMPP and SMS. It works on mobile as well as on desktop platforms. It's based on libpurple and ModemManager.

Meanwhile is a library for connecting to a LIM (Lotus Instant Messaging, formerly Lotus Sametime, formerly VPBuddy) community. It uses a protocol based in part off of the IMPP draft(*1), and in part off of traces of TCP sessions from existing clients.

Toxic is a console-based instant messaging client, using c-toxcore and ncurses. It provides audio calls, sound and desktop notifications, and Python scripting support.

uTox is a lightweight Tox client. Tox is a distributed and secure instant messenger with audio and video chat capabilities.

senpai is an IRC client that works best with bouncers.

Pidgin is a modular instant messaging client that supports many popular chat protocols.

Gajim aims to be an easy to use and fully-featured XMPP chat client. It is extensible via plugins, supports end-to-end encryption (OMEMO and OpenPGP) and available in 29 languages.

Mcabber is a small XMPP (Jabber) console client, which includes features such as SASL and TLS support, Multi-User Chat (MUC) support, logging, command-completion, OpenPGP encryption, Off-the-Record Messaging (OTR) support, and more.

Pidgin-OTR is a plugin that adds support for OTR to the Pidgin instant messaging client. OTR (Off-the-Record) Messaging allows you to have private conversations over instant messaging by providing: (1) Encryption: No one else can read your instant messages. (2) Authentication: You are assured the correspondent is who you think it is. (3) Deniability: The messages you send do not have digital signatures that are checkable by a third party. Anyone can forge messages after a conversation to make them look like they came from you. However, during a conversation, your correspondent is assured the messages he sees are authentic and unmodified. (4) Perfect forward secrecy: If you lose control of your private keys, no previous conversation is compromised.

This package provides Python bindings to Zulip's API.

BitlBee brings IM (instant messaging) to IRC clients, for people who have an IRC client running all the time and don't want to run an additional IM client. BitlBee currently supports XMPP/Jabber (including Google Talk), MSN Messenger, Yahoo! Messenger, AIM and ICQ, and the Twitter microblogging network (plus all other Twitter API compatible services like identi.ca and status.net).

MQTT and MQTT-SN are lightweight publish/subscribe messaging transports for TCP/IP and connection-less protocols (such as UDP). The Eclipse Paho project provides client side implementations of MQTT and MQTT-SN in a variety of programming languages. This package is for the Python implementation of an MQTT version client class.

libsignal-protocol-c is an implementation of a ratcheting forward secrecy protocol that works in synchronous and asynchronous messaging environments. It can be used with messaging software to provide end-to-end encryption.

Poezio is a free console XMPP client (the protocol on which the Jabber IM network is built). Its goal is to let you connect very easily (no account creation needed) to the network and join various chatrooms, immediately. It tries to look like the most famous IRC clients (weechat, irssi, etc). Many commands are identical and you won't be lost if you already know these clients. Configuration can be made in a configuration file or directly from the client. You'll find the light, fast, geeky and anonymous spirit of IRC while using a powerful, standard and open protocol.

libqmatrixclient is a Qt library to write clients for the Matrix instant messaging protocol. Quaternion is the reference client implementation. Quaternion and libqmatrixclient together form the QMatrixClient project.

C library implementation of the Tox encrypted messenger protocol.