# Device onboarding

Source: https://cumulocity.com/docs/data-preparation/device-onboarding/
Sector: Device management & connectivity
Release: Latest

When a data preparation rule produces a message containing an external ID that does not yet exist in Cumulocity, the platform automatically creates a new device and associates that external ID with it. This ensures that data flowing through your rules is never lost due to a missing device.

### Automatically created devices {#automatically-created-devices}

Each automatically created device is configured with the following properties:

| Property | Value |
|----------|-------|
| `name` | `Auto generated device for {externalIdType}/{externalId}` |
| `type` | `c8y_GeneratedDeviceType` |
| `c8y_IsDevice` | `{}` |
| `com_cumulocity_model_Agent` | `{}` |

The external ID that triggered the creation is registered as an external identity for the new device.


> **Info:**
> The properties of automatically created devices cannot be customized.