Top 8 FAQs about UDID on iPhone
A UDID is a unique, permanent identifier for every iOS device used mainly for app development and beta testing. You can find your UDID via iTunes, Finder app on Mac, or secure browser-based methods by installing a temporary profile. Always protect your UDID and register it in your Apple Developer account to test apps on your device.
Understanding the UDID (Unique Device Identifier) is essential for iPhone users involved in app development and beta testing.
This guide offers clear, step-by-step instructions on how to find your iPhone’s UDID using different methods, explains its significance, and shows how to register it in your Apple Developer account.
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Key takeaways
UDID (unique device identifier) is a permanent identifier for each iOS device that cannot be changed. You can get your iPhone’s UDID through iTunes, Finder app, or browser-based configuration profiles
UDID is essential for iOS app development, beta testing, and registering devices in Apple Developer accounts
Never share your device’s UDID with untrusted parties to protect your device from security risks. Different iPhone models use different UDID formats, with newer devices using shorter identifiers
1. What is a UDID and why do I need it for my iPhone?
A UDID (unique device identifier) is a permanent alphanumeric string that Apple assigns to every iOS device, including iPhone, iPad, and iPod Touch.
This unique identifier serves as a digital fingerprint that distinguishes your individual device from millions of other iOS devices worldwide.
You need your iPhone’s UDID primarily for app development — be it a native app, webview app, or hybrid app— and beta testing.
When developers want to test iOS apps on specific devices before releasing them to the App Store, they must register those devices using their UDIDs in their Apple Developer account.
This process ensures that only authorized devices can install and test pre-release software. Additionally, the UDID helps Apple servers communicate with your device for activation, security verification, and feature management.
2. How can I get my iPhone’s UDID using iTunes?
To find your iPhone’s UDID using iTunes, connect your device to your computer with a USB cable and open iTunes.
Once iTunes recognizes your iPhone, click on the device icon that appears in the upper-left corner.
In the device summary screen, you’ll see your iPhone’s information including the serial number.
Click on the serial number text, and it will cycle through different identifiers including your device’s UDID.
When the UDID appears (it will be a long string of letters and numbers), right-click on it and select “Copy” to save it to your clipboard.
This method works reliably on Windows computers and older macOS versions where iTunes is still available.
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3. Can I get my UDID using the Finder app on Mac?
Yes, if you’re using macOS Catalina or later, you can get your iPhone’s UDID through the Finder app since Apple replaced iTunes functionality with Finder.
Connect your iPhone to your Mac using a USB cable, then open Finder and look for your device in the sidebar under “Locations.”
Click on your iPhone in the Finder sidebar, then select the “General” tab. You’ll see your device information including the device name and serial number.
Click on the device name text multiple times to cycle through different identifiers until your UDID appears. You can then copy this unique device ID for use in your Apple Developer account or beta testing applications.
4. Is it safe to use browser-based methods to find the UDID?
Browser-based methods like Median.co's UDID Retrieval Utility are safe when used correctly but require installing a temporary configuration profile on your iPhone.
This profile allows third-party websites to access and display your device's UDID and related information directly in your browser. Median.co provides a secure and straightforward way to get your UDID without a computer.
Simply visit their site on a desktop or your iPhone, follow the prompts to install the small configuration profile, and retrieve your UDID along with details like device model and serial number. The process uses encryption to protect your private data.
Once you have copied your UDID, immediately remove the downloaded profile to maintain security. Go to Settings > General > VPN & Device Management and delete any unnecessary profiles.
Always use trusted sites like Median.co to avoid exposing your UDID to untrusted parties.
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5. Why does my iPhone XS have a different UDID format than older iPhones?
Apple changed the UDID format for iPhone XS, iPhone XS Max, and newer iOS devices starting in 2018.
While older devices like iPhone X and earlier models use a 40-character hexadecimal string, newer devices including iPhone XS and later use a 25-character format with a dash after the eighth digit.
For example, an older device might have a UDID like “a1b2c3d4e5f6g7h8i9j0k1l2m3n4o5p6q7r8s9t0”, while an iPhone XS would display something like “ABCDEF12-34567890ABCDEF12”.
This change reflects Apple’s updated hardware security features and device identification systems. Both formats work perfectly for app development and beta testing purposes.
6. How many devices can I register with my Apple Developer account using UDIDs?
Apple allows developers to register up to 100 devices per device type per membership year in their Apple Developer account.
This means you can register 100 iPhones, 100 iPads, 100 Apple TVs, and 100 Apple Watches separately. Each device must be registered using its unique device identifier before you can install beta or ad hoc apps on it.
These device slots reset annually when your developer membership renews, but you cannot remove devices mid-year to free up slots.
Plan carefully when adding devices to your developer account, especially if you’re working with multiple testers or team members who need access to your beta apps.
You can access your registered devices through the “Certificates, IDs & Profiles” section of your Apple Developer account.
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7. Can I change or reset my iPhone’s UDID?
No, you cannot change, reset, or modify your iPhone’s UDID under any circumstances. The unique device identifier is permanently assigned to your physical device during manufacturing and remains constant throughout the device’s entire lifetime.
Even if you perform a factory reset, install a new iOS version, or completely erase your iPhone, the UDID remains exactly the same.
This permanence is intentional and serves important security and identification purposes for Apple servers, app development, and device management systems.
If you need a different identifier for privacy reasons, developers typically use resettable identifiers like IDFA or app-specific UUIDs instead of the UDID for user tracking or analytics.
8. How do I add my UDID to my Apple Developer account for beta testing?
To add your iPhone’s UDID to your Apple Developer account, follow these steps:
Log into your Apple Developer account at the Apple Developer website
Navigate to the “Certificates, IDs & Profiles” section
Click on “Devices” in the sidebar menu
Select “All” or choose “iPhone” depending on your device type
Click the “+” button to register a new device
Enter your device’s UDID in the “Device ID” field
Provide a recognizable device name (e.g., “John’s iPhone 12” or “Testing Device 1”)
Click “Continue” to proceed
Click “Register” to add the device to your account
Update or create new provisioning profiles that include this device
Use the updated provisioning profile to install beta or ad hoc apps on your iPhone
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Summary
A UDID (Unique Device Identifier) is a permanent, unique alphanumeric code assigned to every iOS device, used primarily for app development and beta testing.
Developers register devices using their UDIDs in the Apple Developer account to authorize installation of pre-release apps.
The UDID can be found via iTunes on Windows or older macOS, the Finder app on macOS Catalina and later, or through secure browser-based methods that require installing a temporary configuration profile.
Newer iPhone models use a different UDID format, but all serve the same purpose. Apple limits developers to registering 100 devices per device type annually.
The UDID cannot be changed or reset. To enable beta testing, the UDID must be added to the Apple Developer account, and any temporary profiles installed to retrieve the UDID should be removed afterward to ensure security.
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