Connect an MQTT broker

InduQT subscribes to your broker, reads JSON messages and maps each one to a machine and its signals. The broker must be reachable from the internet; TLS (mqtts:// or wss://) is strongly recommended.

Set up

1. Create the site and machines

   Create them in the app or with POST /v1/sites and POST /v1/machines. Set each machine's externalId to the name your source uses (for example B-101), so messages can address it without knowing InduQT ids.

2. Create a broker user for InduQT

   Give it read (subscribe) access to the telemetry topics only.

3. Add the connector

   In the app: open the site and choose MQTT broker. Or with the API, using a key with the write scope:

   POST /v1/connectorsCopy

   curl -X POST "https://api.induqt.ai/v1/connectors" \
     -H "Authorization: Bearer $INDUQT_API_KEY" \
     -H "Content-Type: application/json" \
     -d '{
     "siteId": "6f1c2c0e-4b1a-4c55-9d0e-1f2a3b4c5d6e",
     "type": "mqtt",
     "name": "Boiler house broker",
     "config": {
       "url": "mqtts://broker.example.com:8883",
       "topic": "plant/+/telemetry",
       "username": "induqt",
       "password": "…",
       "qos": 1
     },
     "mapping": {
       "machineFrom": "topic",
       "topicLevel": 1,
       "autoCreate": true
     }
   }'

4. Check it is connected

   GET /v1/connectors shows status, lastMessageAt and lastError.

Settings and mapping

Mapping. machineFrom: "topic" (use topicLevel, 0-based) | "payload" (machineField, default "machine") | "fixed" (machine). Values: valuesField (default: every numeric top-level field), timestampField (default "ts"). Sparkplug B is not decoded yet.

Mapping by topic

When the machine is part of the topic, use machineFrom: "topic". Topic levels count from 0: in plant/B-101/telemetry, level 1 is B-101, matched against the machine's externalId.

{
  "machineFrom": "topic",
  "topicLevel": 1,
  "autoCreate": true
}

Mapping by payload

When many machines share one topic, name the machine inside the message and point valuesField at the object holding the numbers.

{
  "machine": "B-101",
  "ts": "2026-10-27T03:12:09Z",
  "values": {
    "steam_pressure": 112.4,
    "flue_o2": 3.2
  }
}

{
  "machineFrom": "payload",
  "machineField": "machine",
  "valuesField": "values",
  "timestampField": "ts"
}

For a topic that only ever carries one machine, use { "machineFrom": "fixed", "machine": "B-101" }.

Test with mosquitto_pub

mosquitto_pub -h broker.example.com -p 8883 --capath /etc/ssl/certs \
  -u plant-gateway -P "$MQTT_PASSWORD" -q 1 \
  -t plant/B-101/telemetry \
  -m '{"ts":"2026-10-27T03:12:09Z","steam_pressure":112.4,"steam_flow":2.1}'

Then check the value arrived with GET /v1/machines/{machineId}/latest.

Troubleshooting