Let's Chat — Self-hosted chat for small teamsWay back in 2012, we didn't like any of the existing chat services out there. So we decided to write our own. Let's Chat is a persistent messaging application that runs on Node.js and MongoDB. It's designed to be easily deployable and fits well with small, intimate teams. It's free (MIT licensed) and ships with killer features such as LDAP/Kerberos authentication, a REST-like API and XMPP support.
Mattermost
