Self-hostable software: XMPP Servers (8)

ejabberd is an open-source, scalable realtime platform that includes an XMPP server, MQTT broker, and SIP service.

Openfire is an open-source XMPP server for real-time collaboration and instant messaging.

MongooseIM is a scalable XMPP server platform for building instant messaging systems.

An open source instant messaging transport that lets users chat across different IM networks.

Snikket is an open-source, self-hosted personal messaging service with Docker-based server images.

Tigase XMPP Server is a highly optimized, modular, and flexible XMPP/Jabber server written in Java.

Feature-rich and easy to configure XMPP server.

Community project to develop, design and promote personal servers running free software for private, personal, communications.