# Enable notifications for Sidewalk device registration state events
Sidewalk device registration state events

Device registration state events publish event notifications when there is a change in the device registration state, such as when a Sidewalk device has been provisioned or registered. The events provide you information about the different states that the device goes through from when it's provisioned to when it has been registered.

## How device registration state events work


When you onboard your Sidewalk device with Amazon Sidewalk and AWS IoT Wireless, AWS IoT Wireless performs a `create` operation and adds your Sidewalk device to your AWS account. Your device then enters the provisioned state and the `eventType` becomes `provisioned`. For more information about onboarding your device, see [Get started using AWS IoT Core for Amazon Sidewalk](sidewalk-getting-started.md).

After the device has been `provisioned`, Amazon Sidewalk performs a `register` operation to register your Sidewalk device with AWS IoT Wireless. The registration process starts, where the encryption and session keys are set up with AWS IoT. When the device is registered, the `eventType` becomes `registered`, and your device is ready to use.

After the device has been `registered`, Sidewalk can send a request to `deregister` your device. AWS IoT Wireless then fulfills the request and changes the device state back to `provisioned`. For more information about the device states, see [DeviceState](https://docs.aws.amazon.com/iot-wireless/latest/apireference/API_SidewalkDeviceMetadata.html#iotwireless-Type-SidewalkDeviceMetadata-DeviceState). 

## Enable notifications for device registration state events


Before subscribers to the device registration state reserved topics can receive messages, you must enable event notifications for them from the AWS Management Console, or by using the API or CLI. You can enable these events for all Sidewalk resources in your AWS account or for select resources. For information about how to enable these events, see [Enable events for wireless resources](iot-wireless-control-events.md). 

## Format of MQTT topics for device registration state events


To notify you of device registration state events, you can subscribe to MQTT reserved topics that begin with a dollar (\$1) sign. For more information, see [MQTT topics](https://docs.aws.amazon.com/iot/latest/developerguide/topics.html) in the *AWS IoT developer guide*. 

Reserved MQTT topics for Sidewalk device registration state events use the following format:
+ For resource-level topics:

  `$aws/iotwireless/events/{eventName}/{eventType}/sidewalk/wireless_devices`
+ For identifier topics:

  `$aws/iotwireless/events/{eventName}/{eventType}/sidewalk/{resourceType}/{resourceID}/{id}`

Where:

**\$1eventName\$1**  
\$1eventName\$1 must be `device_registation_state`.

**\$1eventType\$1**  
\$1eventType\$1 can be `provisioned` or `registered`.

**\$1resourceType\$1**  
\$1resourceType\$1 can be `sidewalk_accounts` or `wireless_devices`.

**\$1resourceID\$1**  
\$1resourceID\$1 is `amazon_id` for \$1resourceType\$1 of `sidewalk_accounts` and `wireless_device_id` for \$1resourceType\$1 of `wireless_devices`.

You can also use the `+` wildcard character to subscribe to multiple topics at the same time. The `+` wildcard character matches any string in the level that contains the character. For example, if you want to be notified of all possible event types (`provisioned` and `registered`) and for all devices registered to a particular Amazon ID, you can use the following topic filter:

`$aws/iotwireless/events/device_registration_state/+/sidewalk/sidewalk_accounts/amazon_id/+`

**Note**  
You can't use the wildcard character `#` to subscribe to the reserved topics. For more information about topic filters, see [MQTT topic filters](https://docs.aws.amazon.com/iot/latest/developerguide/topicfilters.html) in the *AWS IoT developer guide*.

## Message payload for device registration state events


After you enable notifications for device registration state events, event notifications are published over MQTT with a JSON payload. These events contain the following example payload:

```
{    
    "eventId": "string", 
    "eventType": "provisioned|registered", 
    "WirelessDeviceId": "string",
    "timestamp": "timestamp",

    // Event-specific fields
    "operation": "create|deregister|register", 
    "Sidewalk": {
        "AmazonId": "string",
        "SidewalkManufacturingSn": "string"
    }
}
```

The payload contains the following attributes:

**eventId**  
A unique event ID (string).

**eventType**  
The type of event that occurred. Can be `provisioned` or `registered`.

**wirelessDeviceId**  
The identifier of the wireless device.

**timestamp**  
The Unix timestamp of when the event occurred.

**operation**  
The operation that triggered the event. Valid values are `create`, `register`, and `deregister`. 

**sidewalk**  
The Sidewalk Amazon ID or `SidewalkManufacturingSn` for which you want to receive event notifications.