Device Identity Messages

To retrieve device configuration, attributes, settings, rules, child devices, and pending commands/OTAs — the device sends a JSON message with a specific message type (mt) to the di topic. The platform responds with the requested data.

Message types

mt	Description	Applies To
200	Get Device Hello Message	All devices
201	Get Device Template Attributes	All devices
202	Get Device Template Settings/Twin	All devices
203	Get Edge Rule	Edge devices only
204	Get Child Devices	Gateway devices only
205	Get Pending OTAs	All devices
206	Get Pending Commands	All devices
209	Get Pending OTAs and Commands	All devices
221	Create Child Device	Gateway devices only
222	Delete Child Device	Gateway devices only

All messages are published to the di topic from the Identity API response. The platform responds on the c2d topic.

mt: 200 — Hello Message

Send this as the FIRST message after MQTT connection. Returns device metadata, protocol info, and ability flags.

mt: 201 — Get Attributes

Fetch template attribute definitions. Required before sending telemetry — platform will reject data if attributes are not synced.

mt: 202 — Get Settings/Twin

Fetch device twin/shadow desired properties defined in the template.

mt: 204 — Get Child Devices

Gateway devices only. Retrieves list of registered child devices.

mt: 205 — Get Pending OTAs

Check for pending firmware updates queued for this device.

mt: 221 — Create Child Device

Gateway devices can dynamically register new child devices.

mt: 222 — Delete Child Device

Gateway devices can remove decommissioned child devices.

ⓘ NOTE

Always send mt: 200 (Hello Message) as the first message after MQTT connection. Check the has object in the response to determine which additional messages to send (201 for attributes, 202 for settings, 204 for child devices, etc.).