Matrix

Matrix is a open standard for decentralised real-time communication, providing simple HTTP APIs and open source reference implementations for securely distributing and persisting JSON over an open federation of servers. Matrix is designed to defragment all the existing communication silos, and the ecosystem provides bridges into IRC, Slack, Gitter and other systems. Typical uses include group chat (with no single point of control), voice/video calling and conferencing, file transfer and IoT data transfer.

Protocols
Anonymity
I2P
Tor
Communication
DNS
IRC
Matrix
SIP
Tox
XMPP
Encryption
GPG
OMEMO
OTR
S/MIME
SSL/TLS
ZRTP
Synchronization
ActiveSync
CalDAV
CardDAV
WebDAV
Syndication
RSS