ngIRCd is a lightweight Internet Relay Chat (IRC) server for small or private networks. It is easy to configure, can cope with dynamic IP addresses, and supports IPv6, SSL-protected connections, as well as PAM for authentication.

Profanity is a console based XMPP client written in C using ncurses and libmesode, inspired by Irssi.

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.

pounce is a multi-client, TLS-only IRC bouncer. It maintains a persistent connection to an IRC server, acting as a proxy and buffer for a number of clients.

jj is a simple file-system-based Jabber client, inspired by ii IRC client. Interaction with jj is done by writing and reading files from the server directory which jj creates. It is perfect for bots and notifications.

This package provides python-pypresence, a Discord RPC client written in Python.

This package provides Ejabberd -- Robust, Ubiquitous and Massively Scalable Messaging Platform. It supports XMPP, MQTT and SIP 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.

senpai is an IRC client that works best with bouncers.

This module implements XEP-0198: when supported by both the client and server, it can allow clients to resume a disconnected session, and prevent message loss.

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.

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.

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.

gloox is a full-featured Jabber/XMPP client library, written in ANSI C++. It makes writing spec-compliant clients easy and allows for hassle-free integration of Jabber/XMPP functionality into existing applications.

mtxclient is a C++ library that implements client API for the Matrix protocol. It is built on to of Boost.Asio.

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.

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.

Quaternion is a Qt desktop client for the Matrix instant messaging protocol. It uses libqmatrixclient and is its reference client implementation.

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.

pn provides a command line tool that allows users to operate on phone numbers (get validity information, reformat them, or extract numbers from a text snippet), using libphonenumber.

HexChat lets you connect to multiple IRC networks at once. The main window shows the list of currently connected networks and their channels, the current conversation and the list of users. It uses colors to differentiate between users and to highlight messages. It checks spelling using available dictionaries. HexChat can be extended with multiple addons.

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.

C library implementation of the Tox encrypted messenger protocol.

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