In shortSparkplug B is an open industrial specification (Eclipse Sparkplug) that defines topic naming, a Protobuf-based payload format and device state management (birth/death certificates) on top of MQTT.
MQTT is a transport protocol and leaves topic names and payload format open. Sparkplug narrows that freedom so devices from different vendors speak the same structure. The topic structure is spBv1.0/group/message_type/edge_node/device; message types include NBIRTH, NDEATH, DBIRTH, DDEATH, NDATA, DDATA, NCMD and DCMD.
Birth messages announce which data points a node or device has; death messages let consumers know data has gone stale when a connection drops. The payload is Protobuf-encoded and therefore not directly human-readable.
Sparkplug is not the only option for every plant. Defining your own hierarchical topics and JSON payloads is also common; the choice depends on your ecosystem and tooling.
In OPC Router projects
OPC Router’s Sparkplug plug-in is used to configure MQTT-based industrial messaging flows. Scope and version compatibility are confirmed in the project.
Frequently asked questions
Is a Sparkplug B payload human-readable?
No; it is Protobuf-encoded. You need a Sparkplug-aware client or converter to read it.