Robust, Ubiquitous and Massively Scalable Messaging Platform (XMPP, MQTT, SIP Server)

Jitsi is an audio/video and chat communicator that supports protocols such as SIP, XMPP/Jabber, IRC and many other useful features.

Web-based XMPP/Jabber chat written in JavaScript

An XMPP server licensed under the Open Source Apache License.

A modular and portable open source XMPP client library written in Java for Android and Java (SE) VMs

Modern XMPP ("Jabber") Chat Client using GTK/Vala

MongooseIM is Erlang Solutions' robust, scalable and efficient XMPP server, aimed at large installations. Specifically designed for enterprise purposes, it is fault-tolerant and can utilise the resources of multiple clustered machines.

?? Instant messaging server for the Extensible Messaging and Presence Protocol (XMPP).

Ncurses based XMPP client

An IRC to other chat networks gateway ??

Cross-platform real-time collaboration client optimized for business and organizations.

Monal for XMPP (iOS and macOS)

Go XMPP Library (From Yasuhiro Matsumoto and based on the code from Russ Cox)

Miranda NG: Next Generation of Miranda IM

JabberD XMPP Server

Adium is an open source and free instant messaging application for macOS that can connect to XMPP (Jabber), IRC and more.

(M) Highly optimized, extremely modular and very flexible XMPP/Jabber server

XEP-0384: OMEMO Encryption for libpurple.

(M) XMPP client for macOS based on TigaseSwift XMPP library

(M) Public Project of Tigase Messenger for iOS devices based on Tigase Swift XMPP library.