MQTT Sparkplug B Monitor is your go‑to tool for developing, testing, and operating IoT/IIoT systems — with native Sparkplug B and MQTT 5 support. Create connections, live‑subscribe to topics, view message details with syntax highlighting, publish messages, export your tracked log and reuse your favorites. Features: Fast navigation with saved favorites for connections, topics and different types of messages. MQTT 3.1.1 & 5: QoS 0–2, retain, content type, user properties, response topic, correlation data. Sparkplug B: Send NBIRTH/NDATA/NDEATH/DBIRTH/DDATA/DDEATH, pick metric types. Publish: Fast sending, JSON validation, reusable favorites with placeholders. Subscribe: Live view, wildcards, filters, history. Connections: Websocket, TLS/SSL, username/password UX: Clean, fast, optimized for testing and debugging Perfect for device bring‑up, telemetry testing, backend integration, and Sparkplug B PoCs