Every iOS developer and power user has, at some point, needed to locate the Unique Device Identifier, or UDID, for a specific iPhone. This string of characters and numbers is the digital fingerprint of the device, essential for enterprise app distribution, beta testing with TestFlight, and registering devices for development with Apple. Understanding how to retrieve this identifier is a fundamental skill, but the process has evolved significantly with changes in iOS security and the introduction of different tools. This guide walks through the modern methods, moving from the simplest graphical interface to the more technical command-line approaches.
Why You Need a iPhone UDID
The UDID serves as the foundational serial number for iOS devices, linking a specific phone to developer accounts and provisioning profiles. In the past, it was the primary requirement for installing ad-hoc applications that bypassed the App Store. While Apple has shifted towards using devices and ports for authorization, the UDID remains a critical piece of information for developers managing device logs, creating custom enterprise deployments, or troubleshooting deep system issues. Without this identifier, certain advanced configurations and distributions are simply not possible.
Finding UDID via Apple Configurator 2
The most reliable and officially supported method for retrieving the UDID today involves Apple Configurator 2, a free application available on the Mac App Store. This tool was designed for IT professionals to manage large fleets of devices, but it is perfect for our needs. The process creates a trusted connection that allows the computer to see the device’s raw data, including the identifier, without relying on the locked-down interface of iTunes.
Step-by-Step Guide
Download and install Apple Configurator 2 from the Mac App Store.
Connect your iPhone to the Mac using a certified USB cable.
Open Apple Configurator 2 and select your device from the sidebar.
Click the "Info" button, which resembles a lowercase "i" in a circle.
The UDID will be displayed prominently at the top of the information panel.
Using Xcode to Locate the Identifier
For developers who already have Xcode installed, the Devices and Simulators window provides another straightforward path to the UDID. This method is ideal for those who are already deep in the development workflow and have the Xcode ecosystem open. It requires the device to be trusted on the machine and recognized by the system.
Procedure in Xcode
First, connect your iPhone to the Mac and unlock it if prompted. Open Xcode and navigate to Window > Devices and Simulators from the top menu. In the sidebar that appears, select your connected device. Similar to Apple Configurator, the device summary will load, and the UDID will be listed near the top of the details pane, usually formatted as a clickable link that can be easily copied.
The Command-Line Approach with libimobiledevice
Users who prefer the terminal or operate within Linux environments can utilize the libimobiledevice suite. This is a collection of open-source tools that provide low-level communication with iOS devices. While this method is highly efficient for scripting and automation, it requires the user to have command-line proficiency and the necessary libraries installed beforehand.
Terminal Commands
After ensuring the library is installed, open the terminal and type idevice_id -l . This command queries the connected device and prints the UDID directly to the console. It is a quick, no-frills approach that eliminates the graphical overhead of the other methods, making it the go-to solution for automated workflows or remote server management.
