Knowledge Base

MQTT Publish

Publishes a message to an MQTT broker topic. Common for IoT actuation and telemetry forwarding.

When to use

  • Command smart devices (lights, relays, HVAC).
  • Forward processed data to a central broker.
  • Integrate with Home Assistant, Mosquitto, or cloud MQTT.

Properties

PropertyTypeDescription
Broker HosttextHostname or IP. Default localhost. Supports {{$var.mqttHost}}.
PortnumberDefault 1883.
UsernametextOptional broker username.
PasswordsecretOptional broker password.
TopictextTarget topic. Required.
PayloadtextareaMessage body; JSON or plain text.
Merge pipeline input into payloadtoggleDefault on.
Retain MessagetoggleMQTT retain flag.
QoSselect0 At most once, 1 At least once (default), 2 Exactly once.

Outputs

Confirmation with topic, payload echo, and broker ack metadata.

See also

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