# Downlink

Sending a **downlink** allows to control or configure physical devices from the cloud. The **downlink** action can be used to send downlinks based on applied business logic. For example, if the temperature exceeds a certain threshold then close the blinds.

It is possible to select one or more **MQTT- or LoRa devices** with the same Data Flow for which the downlink should be triggered.

{% hint style="info" %}
Sending downlinks is **only possible for MQTT- and LoRa-devices.** It is not possible for HTTP-, CoAP- or Sigfox devices.
{% endhint %}

Following downlink message type has to be entered for:

* **LoRaWAN**
  * port (an integer value)
  * confirmed (a boolean value)
  * payload hex string or JSON object (requires a downlink encoder in the device type)
* **MQTT**
  * topic (a string) - The optional topic added here will be appended to the downlink topic to which the downlink is published to e.g. when providing "myTopic" the resulting downlink topic will look as follows: /down/\<secret>/id/\<deviceID>/myTopic.
  * payload as a JSON object - it is possible to use template variables "key": "{{data.temperature}}".

![Downlink template](/files/Br9PKg3FOKnPH5yNWSjW)


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# Agent Instructions: Querying This Documentation

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Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
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```

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Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.