This document specifies the core features of the Extensible Messaging and Presence Protocol (XMPP), an open XML protocol for near-real-time messaging, presence, and request-response services. XMPP is designed to exchange structured information between any two network endpoints using XML elements. The document outlines the protocol's architecture, addressing scheme, XML streams, and security mechanisms. It also includes detailed specifications for XML stanzas, TLS negotiation, and SASL authentication. The core features are intended to support instant messaging and presence applications as defined in RFC 2779. The document provides guidelines for server and client implementation, including server rules for handling XML stanzas, XML usage within XMPP, compliance requirements, internationalization considerations, security considerations, and IANA considerations.This document specifies the core features of the Extensible Messaging and Presence Protocol (XMPP), an open XML protocol for near-real-time messaging, presence, and request-response services. XMPP is designed to exchange structured information between any two network endpoints using XML elements. The document outlines the protocol's architecture, addressing scheme, XML streams, and security mechanisms. It also includes detailed specifications for XML stanzas, TLS negotiation, and SASL authentication. The core features are intended to support instant messaging and presence applications as defined in RFC 2779. The document provides guidelines for server and client implementation, including server rules for handling XML stanzas, XML usage within XMPP, compliance requirements, internationalization considerations, security considerations, and IANA considerations.