Downlink

Send a downlink to one or more devices when a rule condition is true.

A downlink action sends a command or configuration to devices when a rule condition is true. For example, close the blinds when the temperature exceeds a threshold.

Select one or more devices that use the same data flow as targets.

Downlinks are supported for LoRaWAN, MQTT, and CoAP devices. HTTP devices cannot receive downlinks.

Downlink fields

LoRaWAN

A LoRaWAN downlink action

Field	Description
Port	An integer.
Confirmed	Whether the device has to confirm the downlink.
Payload	A hex string. A JSON object is also accepted if the device type has a downlink encoder.

MQTT

Field	Description
Topic	Optional. Appended to the downlink topic of the device. For example, myTopic publishes to /down/<secret>/id/<deviceID>/myTopic.
Payload	A JSON object.

The payload can use payload templating to include data from the rule:

{
  "key": "{{data.temperature}}"
}

CoAP

Field	Description
Raw or Encoder	With Raw, the payload is sent to the device as entered and the encoder of the device type is bypassed. With Encoder, the device type encoder converts the payload first.
Payload	A JSON object.
Confirmed downlink	The device confirms delivery with a CoAP acknowledgment. Without it, the device has to confirm the command in a later uplink.
Clear queue	Removes all pending commands of the device before this one is queued. When off, the command is added to the end of the queue.

CoAP downlinks are queued. The device fetches pending commands when it wakes up, one command per request, and only over DTLS. See CoAP downlinks for the delivery details.