MQTT Quick Test

This page gives you a ready-to-run MQTT telemetry path for Simple IoT's built-in broker.

1. Use the seeded demo device

Docker Compose enables the optional demo telemetry seed by default with:

SIMPLE_IOT_DEMO_SEED_ENABLED=true

On startup the backend creates an idempotent demo dataset:

Item	Value
Product	Demo Smart Sensor
Product key	demo-smart-sensor
Device	Demo Sensor 001
Device key / MQTT username	demo-sensor-001
Device secret / MQTT password	demo-secret
Protocol	demo-json-telemetry
Alarm rule	temperature > 60 creates demo_high_temperature

To disable the seed for a production-like deployment, set SIMPLE_IOT_DEMO_SEED_ENABLED=false in .env and recreate iot-server.

2. Publish telemetry

Simple IoT's default MQTT driver uses:

Field	Default format
Client ID	simple_{deviceKey}
Username	{deviceKey}
Password	device secret
Property topic	simpleiot/pro/{productKey}
Event topic	simpleiot/ev/{productKey}
Service reply topic	simpleiot/cam_res/{productKey}

Publish a high-temperature sample to the seeded device:

mosquitto_pub -h localhost -p 1883 \
  -i simple_demo-sensor-001 \
  -u demo-sensor-001 \
  -P demo-secret \
  -t simpleiot/pro/demo-smart-sensor \
  -m '{"temperature":72.5,"humidity":43,"voltage":220.8,"online":true,"mode":"auto"}'

Expected result:

1. The payload is decoded by the demo-json-telemetry JavaScript protocol.
2. Telemetry is written as properties: temperature, humidity, voltage, online, mode.
3. Because temperature is above 60, the demo rule chain creates an active demo_high_temperature alarm.

3. Generate a payload from the simulator

After compiling the backend, the small CLI helper prints the exact connection details and JSON payload:

./mvnw -pl iot-server -am -DskipTests compile
java -cp iot-server/target/classes com.github.dingdaoyi.demo.DemoTelemetrySimulator

Override values for manual smoke runs:

java -cp iot-server/target/classes com.github.dingdaoyi.demo.DemoTelemetrySimulator \
  temperature=55.2 humidity=48 voltage=219.6 mode=manual

If you changed the MQTT driver prefixes in application.yml, pass matching simulator overrides:

java -cp iot-server/target/classes com.github.dingdaoyi.demo.DemoTelemetrySimulator \
  topicPrefix=custom-prefix clientIdPrefix=device_

Topic cheat sheet

Direction	Topic	Purpose
Device → Platform	simpleiot/pro/{productKey}	Property report
Device → Platform	simpleiot/ev/{productKey}	Event report
Platform → Device	simpleiot/cmd/{productKey}	Service invocation
Device → Platform	simpleiot/cam_res/{productKey}	Service reply