XMPP, ‘Extensible Messaging and Presence Protocol is an open communication protocol designed for instant messaging, presence information, and contact list maintenance. Based on XML, it enables the near-real-time exchange of structured data between two or more network entities.’

https://en.wikipedia.org/wiki/XMPP

International standard

‘XMPP also known as Jabber is an open protocol and was released over 20 years ago in 1999 by Jeremie Miller.’

https://takebackourtech.org/xmpp-comeback/ acessed 2021-11-21

See Secure Scuttlebutt (SSB), decentralized web