A Unique Device Identifier (UDID) is a string of characters used to uniquely identify a specific device, such as a smartphone or tablet. UDIDs are typically assigned by the device manufacturer and are stored on the device’s hardware. Mobile app developers and network operators often use them to identify and track specific devices.
UDIDs are typically composed of letters and numbers and can be used to identify a device even if it is restored or has its operating system reinstalled.
Unique Device Identifier (UDID) can be used for a variety of purposes:
- Tracking the number of app downloads from a specific device.
- Identifying the device for push notifications.
- Identifying the device for in-app purchases.
- Identifying the device for usage statistics and analytics.
- Identifying the device for customer service.
However, with the increasing concerns about user privacy, using UDIDs has been discouraged by some companies and organizations, such as Apple, which has deprecated it as iOS 5.0. Instead, they have introduced alternative methods of identifying devices, such as the Identifier for Advertisers (IDFA) and the Vendor Identifier (IDFV), that don’t share the same privacy concerns as UDIDs.
Also, See: Test-driven Development (TDD)