The Device ID component generates a stable, per-device identifier (UTDID) for each mobile device, enabling consistent device recognition across sessions without requiring user login or server-side ID management.
Apps use UTDID to distinguish devices for analytics, risk control, push notification targeting, and other scenarios that require reliable device recognition across sessions.
How it works
When your app calls the Device ID API for the first time, the component generates a UTDID and stores it locally on the device. Subsequent calls return the same UTDID without a network request. The UTDID is app-scoped — all apps integrated with the mPaaS SDK on the same device share the same UTDID value.
ID persistence
UTDID persistence depends on how and when the ID was generated. Use the following table to determine whether UTDID suits your scenario:
|
Scenario |
UTDID behavior |
|
App restart or device reboot |
Unchanged |
|
App data or cache cleared |
Unchanged |
|
App uninstalled and reinstalled |
May change. A new UTDID is generated if the locally stored ID is lost. |
|
Device factory reset |
Changes. The stored UTDID is erased and a new one is generated on next launch. |
|
User switches to a different device |
Changes. Each physical device has its own UTDID. |
|
Multiple apps on the same device (all using mPaaS SDK) |
Unchanged — all apps share the same UTDID. |
Note: UTDID is not guaranteed to be globally unique across all devices at all times. Do not use it as the sole identifier in scenarios that require strict uniqueness guarantees, such as financial transaction deduplication or legal identity verification.
Platform behavior
The component supports Android and iOS. UTDID behavior differs between platforms:
Android
UTDID is stored in the device's local storage. It persists across app updates and reinstalls as long as the device storage is intact. A factory reset or manual deletion of app data regenerates the UTDID.
iOS
UTDID is stored in the iOS Keychain. Because Keychain data persists across app uninstalls, the UTDID survives reinstallation on iOS — unlike on Android, where the UTDID may be regenerated after an uninstall.
Use cases
Analytics and attribution: Identify returning users on the same device without requiring account login.
Risk control: Detect abnormal behavior patterns tied to a specific device.
Push notification targeting: Route notifications to specific devices using a stable device-level identifier.
A/B testing: Assign devices to test groups consistently across sessions.
Limitations
Not suitable for strict uniqueness requirements: UTDID can be regenerated after a factory reset or, on Android, after an uninstall. For scenarios requiring a permanent, unforgeable device fingerprint, combine UTDID with server-side account binding.
Not suitable for cross-platform tracking: A device's Android UTDID and iOS UTDID are independent values. If the same user switches platforms, the device ID changes.
Not a user identity: UTDID identifies a device, not a user account. If multiple users share a device, they all receive the same UTDID.
What's next
[Integrate the Device ID component on Android]()
[Integrate the Device ID component on iOS]()
[API reference for Device ID]()