Openfire

Openfire is a real time collaboration (RTC) server licensed under the Open Source Apache License. It uses the only widely adopted open protocol for instant messaging, XMPP (also called Jabber). Openfire is incredibly easy to setup and administer, but offers rock-solid security and performance.

• Website: http://www.igniterealtime.org/projects/openfire/index.jsp
• GitHub project: https://github.com/igniterealtime/Openfire

Jitsi Meet

Jitsi Meet is a project for the Jitsi community, which is an Open Source WebRTC JavaScript application providing high quality, scalable video conferences.

• Website: https://jitsi.org/jitsi-meet/
• GitHub project: https://github.com/jitsi/jitsi-meet

ConverseJS

A free and open-source XMPP chat client in your browser.

• Website: https://conversejs.org/
• GitHub project: https://github.com/conversejs/converse.js

FreeSWITCH

FreeSWITCH is designed to route and interconnect popular communication protocols using audio, video, text, or any other form of media. First released in January 2006, FreeSWITCH has grown to become the world’s premier open source soft-switch platform. This versatile platform is used to power voice, video, and chat communications on devices ranging from single calls on a Raspberry Pi to large server clusters handling millions of calls. FreeSWITCH powers a number of commercial products from start-ups to Carriers.

• Website: https://freeswitch.com/

ctxPHONE

A simple, open source, javascript SIP phone for web applications.

• Website: https://collecttix.github.io/ctxSip/
• GitHub project: https://github.com/Collecttix/ctxSip