NYACC is set of Guile modules for generating parsers and lexical analyzers. It provides sample parsers, pretty-printers using SXML trees as an intermediate representation, a decent C parser and an `FFI Helper' tool to help create Guile Scheme bindings for C-based libraries. It also provides (partially implemented) compilers based on these parsers to allow execution with Guile as extension languages.

M2-Planet, the PLAtform NEutral Transpiler, when combined with mescc-tools, compiles a subset of the C language into working binaries with introspective steps in between. It is self-hosting and for bootstrapping it also has an implementation in the M1 macro assembly language. M2-Planet is built as Phase-5 of the full source bootstrapping process and is capable of building GNU Mes.

Mescc-tools is a collection of tools for use in a full source bootstrapping process. It consists of the M1 macro assembler, the hex2 linker, the blood-elf symbol table generator, the kaem shell, exec_enable and get_machine.

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.

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.

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.

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.

This module adds the ability to set vCard for MUC rooms. One of the most common use cases is to define avatars for MUC rooms.

Python-nbxmpp is a Python library that provides a way for Python applications to use the XMPP network. This library was initially a fork of xmpppy.

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.

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.

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.

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

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).

weechat-wee-slack is a WeeChat native client for Slack. It provides supplemental features only available in the web/mobile clients such as synchronizing read markers, typing notification, threads (and more)! It connects via the Slack API, and maintains a persistent websocket for notification of events.

This module adds an API for sending and receiving XMPP stanzas.

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

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

Libstrophe is a minimal XMPP library written in C. It has almost no external dependencies, only an XML parsing library (expat or libxml are both supported).

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

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.

C library implementation of the Tox encrypted messenger protocol.

This package provides Eclipse Mosquitto, a message broker that implements the MQTT protocol versions 5.0, 3.1.1 and 3.1. Mosquitto is lightweight and is suitable for use on all devices from low power single board computers to full servers.

The MQTT protocol provides a lightweight method of carrying out messaging using a publish/subscribe model. This makes it suitable for Internet of Things messaging such as with low power sensors or mobile devices such as phones, embedded computers or microcontrollers.

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.