The MQTT integration publishes all the data it receives from the devices as JSON over MQTT. To receive data from your device, you therefore need to subscribe to its MQTT topic. For debugging, you could use a (command-line) tool like mosquitto_sub which is part of the Mosquitto MQTT broker.

MQTT quickstart

Use + for a single-level wildcard, # for a multi-level wildcard. Examples:

mosquitto_sub -t "application/APPLICATION_ID/#" -v                  # display everything for the given APPLICATION_ID
mosquitto_sub -t "application/APPLICATION_ID/device/+/event/up" -v  # display only the uplink payloads for the given APPLICATION_ID


  • MQTT topics are case-sensitive
  • The APPLICATION_ID can be retrieved using the API or using the web-interface, this is not the same as the AppEUI / JoinEUI!


The MQTT integration exposes all events as documented by Event types. The default event topic is: application/APPLICATION_ID/device/DEV_EUI/event/EVENT.

The default topic for scheduling downlink payloads is: application/APPLICATION_ID/device/DEV_EUI/command/down.

The Application ID and DevEUI of the device will be taken from the topic.

Example payload:

    "devEui": "0102030405060708",             // this must match the DEV_EUI of the MQTT topic
    "confirmed": true,                        // whether the payload must be sent as confirmed data down or not
    "fPort": 10,                              // FPort to use (must be > 0)
    "data": "...."                            // base64 encoded data (plaintext, will be encrypted by ChirpStack)
    "object": {                               // decoded object (when application coded has been configured)
        "temperatureSensor": {"1": 25},       // when providing the 'object', you can omit 'data'
        "humiditySensor": {"1": 32}