Eclipse Sparkplug provides an open and freely available specification for how Edge of Network Gateways (Sparkplug Edge Nodes) or native MQTT enabled end devices and Sparkplug Host Applications communicate bi-directionally within an MQTT Infrastructure. This document details the structure and implementation requirements for Sparkplug compliant MQTT Client implementations on both Edge Nodes and Host Applications. It is recognized that MQTT is used across a wide spectrum of application solution use-cases, and an almost indefinable variation of network topologies. To that end the Sparkplug Specification strives to accomplish the three following goals.