XMPP servers

ejabberd is an Extensible Messaging and Presence Protocol (XMPP) application server and an MQ Telemetry Transport (MQTT) broker, written mainly in the Erlang programming language. It can run under several Unix-like operating systems such as macOS, Linux, FreeBSD, NetBSD, OpenBSD and OpenSolaris. Additionally, ejabberd can run under Microsoft Windows. The name ejabberd stands for Erlang Jabber Daemon (Jabber being a former name for XMPP) and is written in lowercase only, as is common for daemon software.

Openfire (previously known as Wildfire, and Jive Messenger) is an instant messaging (IM) and groupchat server for the Extensible Messaging and Presence Protocol (XMPP). It is written in Java and licensed under the Apache License 2.0.

XMPP server and free software