Messenger and Communication Platform/App
Depends on your use case, how much security and features u need.
- https://signal.org/
- https://www.opendesk.eu/
- https://element.io/matrix-in-germany
- https://zulip.com/
- https://discourse.org/about
- https://nextcloud.com/install/
- https://mattermost.com/
- https://screego.net/#/
- https://www.mumble.info/
- https://www.securemessagingapps.com/
- simpleX looks like a honeypot
- https://github.com/session-foundation
- https://element.io/
- irc, couldn't find official docs
- mailing lists
- https://kb.mailbox.org/de/privat
- https://simplelogin.io/
- https://addy.io/
# XMPP
- ejabberd server
- mongooseim server
- dino linux app
- cheogram android app
- OMEMO encryption
- https://search.jabber.network/