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

Available as overlayed chat boxes or as a fullscreen application. See inverse.chat for the fullscreen version.
A plugin architecture based on pluggable.js
Single-user and group chat
Contacts and groups
Multi-user chatrooms (XEP 45)
Chatroom bookmarks (XEP 48)
Direct invitations to chat rooms (XEP 249)
vCard support (XEP 54)
Service discovery (XEP 30)
In-band registration (XEP 77)
Roster item exchange (XEP 144)
Chat statuses (online, busy, away, offline)
Custom status messages
Typing and chat state notifications (XEP 85)
Desktop notifications
File sharing / HTTP File Upload (XEP 363)
Messages appear in all connected chat clients / Message Carbons (XEP 280)
Third person "/me" messages (XEP 245)
XMPP Ping (XEP 199)
Server-side archiving of messages (XEP 313)
Hidden messages (aka Spoilers) (XEP 382)
Client state indication (XEP 352)
Last Message Correction (XEP 308)
OMEMO encrypted messaging (XEP 384)
Supports anonymous logins, see the anonymous login demo.
Translated into 29 languages