Ripcord - A desktop chat client for Discord and Slack
ejabberd SaaS - Realtime XMPP and MQTT Software and Infrastructure as a Service.
Slack - A messaging app for teams who see through the Earth!
Apache Vysper - Apache Vysper aims to be a modular, full featured XMPP (Jabber) server.
Ziggs - Smoothly Share Content Between Devices!
Openfire - Openfire (formerly Wildfire) is a cross-platform instant messaging (IM) and groupchat server.