http://qwikxxeiw4kgmml6vjw2bsxtviuwjce735dunai2djhu6q7qbacq73id.onion/articles/xmpp/intro
It supports most things you ' d expect from an instant messaging software, like: chat (duh?), sending images/videos/other
files, chatrooms (group chats), and even calling (both voice and video). It also supports another great thing: encryption. The biggest problem with XMPP is that many of the clients (apps/programs you use to chat with people) could be better.