This document provides an overview of XMPP and its use for IoT applications. XMPP is an open standard for messaging and presence that allows for global scalability, extensibility, robustness, and security. It supports asynchronous messages, request/response interactions, and publish/subscribe communication patterns. For IoT, XMPP defines interfaces for sensor data, provisioning, control, device discovery, and secure account creation. It provides a standardized way to connect IoT devices and applications.