Extensible Messaging and Presence Protocol (XMPP) is a communications protocol for message-oriented middleware based on XML (Extensible Markup Language). It enables the near-real-time exchange of structured yet extensible data between any two or more network entities.
How the Whatapp Works!
WhatsApp is a real-time messaging application, which makes use of Ejabberd (XMPP) server. This server facilitates instant message transfer between two or many users at any given second.
ERLANG is the programming language used by WhatsApp. Ejabberd is an open source Jabber server written in Erlang language. It was preferred by the techies of WhatsApp as it was suitable for accommodating huge communication system with high sustainability.