MQTT-Debugger

MQTT (Message Queuing Telemetry Transport) is a lightweight messaging protocol widely used in IoT (Internet of Things) applications. It follows a publish/subscribe pattern where clients connect to a broker, subscribe to topics, and publish messages.

Enter the broker address, port, and select WebSocket or secure WebSocket (WSS). Optionally provide username and password for authentication. Click Connect, then subscribe to topics or publish messages. All messages are displayed in the log panel in real time.

MQTT topics are hierarchical paths separated by slashes (e.g., home/livingroom/temperature). Wildcards: + matches a single level, # matches multiple levels. Topics starting with $ are system topics.

QoS 0 — At most once (fire and forget). QoS 1 — At least once (acknowledged delivery). QoS 2 — Exactly once (assured delivery). Higher QoS ensures reliability but increases overhead.