@barszczyk XMPP (aka Jabber) is an open source IM protocol. OMEMO is an extension to XMPP which offers end to end encryption in a manner similar to Signal. An example Android app which uses it is called Conversations.
It is fully decentralised and federated. Not like other instant messaging networks .
Server run by the main developers of the project It is not focused on any particular niche interest - everyone is welcome as long as you follow our code of conduct!