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The Things Stack (TTN / TTS). **Data**, **Devices**, **Gateways**; **Triggers** → **Webhook · Receive Events** from the node picker.

Actions8

Device → Send Downlink

AI-generated

Summary

Send a downlink message to a specified LoRaWAN device within an application using The Things Stack Application Server API.

Inputs

  • Application Name or ID (required) — Select the application where the target device is registered, either by name or ID. This is required to identify the correct application context.
  • Device Name or ID (required) — Select the target device within the chosen application to receive the downlink message by name or ID.
  • FPort (required) — Specify the LoRaWAN application port (1–223) on which to send the downlink payload.
  • Payload Type (required) — Choose the format of the downlink payload: 'Hex' for raw hexadecimal bytes without a prefix or 'JSON (Decoded_payload)' for a JSON object representing the decoded payload.
  • Payload (required) — Enter the downlink payload content in the format selected (Hex string without '0x' prefix or JSON object).
  • Priority (required) — Set the downlink queue priority. Options range from 'LOWEST' to 'HIGHEST' to determine the priority of the downlink message in the queue.
  • Confirmed Downlink — Set whether the downlink requires confirmation (ACK) from the device. Defaults to false (unconfirmed).

Output shape

a single JSON object indicating success, application ID, device ID, operation type, current downlink queue count, details of queued downlinks, and the submitted downlink payload.

This operation calls the POST /down/push endpoint of The Things Stack Application Server API, submitting one downlink message to the specified device. On success, it returns the updated downlink queue state of the device. Errors during payload validation (e.g. invalid hex string, invalid JSON) or API errors will throw a NodeOperationError with detailed context. The downlink payload is encoded as base64 on the backend if provided as hex.

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