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Tester guide

How to find your iPhone UDID in 2026

With or without a computer — and how to send it to the developer so you get a working test build on the first try.

September 2026 · 7 min read

Short answer: the UDID isn’t shown in iPhone Settings. The fastest way is to open udid.tech in Safari on the iPhone, install the short profile it offers and copy the UDID it shows. With a Mac, connect the iPhone and click the text under its name in Finder until the UDID appears.

A developer asked for your UDID so they can let you test their app. Here is what it is, four ways to get it, and the mistakes that most often cost testers a day.

What a UDID is and why developers ask for it

The UDID (Unique Device Identifier) is a long string that identifies one specific iPhone or iPad. Apps outside the App Store and TestFlight can only be installed on devices the developer has registered in their Apple Developer account, and the UDID is how they register yours[1]. Each developer account can register 100 devices per device type per membership year[2] — so developers ask for it precisely, one device at a time.

Giving a developer your UDID doesn’t give them access to your data, photos or Apple Account. It only lets your device install their test builds.

Not in SettingsSettings → General → About shows the serial number, IMEI and other identifiers, but not the UDID[3]. The serial number is not the UDID — sending it instead is the most common mistake.

Method 1: without a computer (udid.tech)

Takes about 30 seconds and works on iPhone and iPad.

  1. Open udid.tech in Safari on the device whose UDID you need. Other browsers can’t install profiles.
  2. Tap Get My UDID and allow the configuration profile to download.
  3. Open Settings and tap Profile Downloaded at the top.
  4. Tap Install and enter your passcode. Safari opens again and shows your UDID — copy it.

How it works: the profile asks iOS to send the device’s identifiers back to the site once, a mechanism Apple built for device enrollment[4]. The service says it doesn’t store your data and the profile is removed right after[5].

If the profile won’t install: this happens — on managed work phones where device management blocks profiles, when the page was opened in a browser other than Safari, or when a previous download is still waiting in Settings. Try Safari, delete the old download in Settings → General → VPN & Device Management, or use a Mac (method 2).

Method 2: Finder on a Mac

  1. Connect the iPhone to the Mac with a cable.
  2. Open Finder and select the iPhone under Locations in the sidebar. Tap Trust on the iPhone and enter the passcode if asked.
  3. In the header under the device name, click the line with the model and storage. Each click switches the information shown; keep clicking until you see the UDID.
  4. Control-click the UDID and choose Copy UDID[1].

Method 3: Xcode Device Hub (for developers)

In Xcode 27, Device Hub replaced the old Devices and Simulators window[6].

  1. Connect and pair the device, then open Xcode → Open Developer Tool → Device Hub (or Manage Devices… in the run destination menu).
  2. Select the device, open Info in the inspector and copy UDID under Hardware Properties. If it’s hidden, use Edit Visibility to show it[1].

On Xcode 26 and earlier the same value is shown as Identifier in Window → Devices and Simulators.

Method 4: Apple Configurator (many devices)

If you register a batch of test devices, Apple Configurator on a Mac saves time: connect the devices, select them and use Actions → Export → Info to export a .deviceids file you can upload to the Apple developer portal in one go[7].

On Windows, Apple’s Devices app shows device details as well; clicking the information under the device name typically cycles to the UDID. Apple doesn’t document this step, so if it doesn’t appear, use method 1.

How to send your UDID to the developer

In our experience, most delays happen here, not in finding the UDID. Send it so the developer can paste it without guessing:

  • Copy and paste, never retype. The UDID is 25 or 40 characters; one wrong character means the build won’t install.
  • One device per line, with a name the developer will recognise: Anna — iPhone 15 Pro — 00008120-001A2B3C4D5E6F7A.
  • Send it to the place the developer asked for — the form, chat or email they gave you — so it doesn’t get lost in a thread.
  • If the install fails, check what grey icons and install errors mean.
  • Wait for a new link. After registering your device the developer has to update the build. An older link won’t work on your phone.
  • Be ready for Developer Mode. When the test app opens for the first time, iOS may ask you to turn it on — here is how to enable Developer Mode, including why it can take an hour.

For developers: where AppSign fits

Collecting UDIDs is only the first step. Every new device means updating the provisioning profile and re-signing the build, and the 100-devices-per-year limit means a mistyped UDID costs a slot until renewal. AppSign keeps registered testers, builds and install links in one place: once a tester’s device is added, every next update simply installs — no repeated back-and-forth.

Sources (checked September 17, 2026)
  1. Apple — Locating device identifiers
  2. Apple — Devices overview
  3. Apple Support — Find the serial number or IMEI on your iPhone, iPad or iPod touch
  4. Apple — Over-the-Air Profile Delivery and Configuration (archive)
  5. udid.tech — service description
  6. Apple — Managing devices in Device Hub
  7. Apple — Apple Configurator User Guide