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Free UDID lookup · no iTunes, no Xcode, no signup

What is my UDID?
Find your iPhone or iPad UDID in 10 seconds.

Your iPhone or iPad's 40-character Unique Device Identifier — the one developers ask for when they need to add you to an iOS beta build. Look it up online from your phone, no Mac and no Lightning cable required.

Detecting your device…
How it works

Three taps, no app to install.

01

Tap the button

Safari downloads a temporary configuration profile to your iPhone or iPad. The download is instant.
02

Install the profile

Open Settings, tap "Profile Downloaded", then "Install". iOS shows an "Unverified Profile" warning — that's normal for any unsigned UDID tool, including ours.
03

Copy your UDID

Your 40-character UDID appears here. Tap Copy and paste it back to whoever asked. iOS removes the profile automatically.
UDID 101

What is a UDID — and why does my developer need mine?

A UDID — short for Unique Device Identifier — is a 40-character hexadecimal string that uniquely identifies a single iPhone, iPad, or iPod touch. Every iOS device has one, baked into the hardware at the factory. It never changes, and no two devices share the same UDID. A typical UDID looks like this:

00008101-001C5C083498801E

If a developer asked "what's your UDID?", you're probably about to be added to a beta build of an app that isn't on the App Store yet. Two scenarios cover almost every reason you'd hear that question:

  • Ad-hoc app distribution — Apple's developer program lets a developer register up to 100 iPhones, iPads, Apple TVs, Apple Watches, and Macs per year for ad-hoc builds. Your UDID is what they register on the Apple Developer Portal.
  • Custom provisioning profiles — When a developer signs an iOS app for direct (off-App-Store) installation, the signed app embeds a provisioning profile that lists every authorised UDID. Without your UDID on the list, iOS refuses to launch the app.

You don't need iTunes, Xcode, a Mac, or even any kind of computer to find your iOS UDID. App On The Go reads it through Apple's Profile Service — the same mechanism Xcode uses behind the scenes when it pairs with a device.

How to find UDID on iPhone or iPad — three options

There are three common ways to look up your UDID. Each one works, but the first is by far the fastest:

  1. This page (recommended) — open apponthego.com/what-is-my-udid.php in Safari on the device, tap Find my UDID, install the temporary profile when iOS prompts, and copy the result. Total time: under a minute. No cable, no Mac, no app to download.
  2. Xcode (Mac only) — connect the device with a USB-C / Lightning cable, open Xcode, choose Window → Devices and Simulators, and the UDID appears under Identifier. Requires a Mac and Apple Developer account in good standing.
  3. iTunes / Finder (legacy) — connect the device, open iTunes (Windows or pre-Catalina Mac) or Finder (Catalina+). Click the device name, then click the Serial Number field repeatedly to cycle through Serial → UDID → ECID → MEID. Requires a USB cable and a working iTunes / Finder install.

For beta testers on the go, option 1 is the only one that doesn't require a computer or cable. That's why every iOS-distribution shop — Diawi, InstallOnAir, AppsOnAir, TestApp.io — offers a UDID lookup like this one.

UDID vs serial number vs IDFA vs IDFV — what's the difference?

iOS exposes a handful of identifiers, and they're often confused. Here's the short version:

  • UDID — hardware-bound, 40 hex characters, never changes. Used for ad-hoc and TestFlight provisioning. This is what your developer asked for.
  • Serial number — also hardware-bound, but shorter (around 12 characters) and printed on the device. Apple Care uses this to look up your warranty. Not used for app provisioning.
  • IDFA (Identifier for Advertisers) — a UUID that the user can reset or zero out from Settings. Used by ad networks to attribute installs.
  • IDFV (Identifier for Vendor) — a UUID scoped per developer team. Resets when the user uninstalls every app from a given vendor.

If a developer asked for your UDID, they need the hardware-bound 40-character one — the IDFA / IDFV won't work for ad-hoc distribution.

Is sharing my UDID safe?

Yes — sharing your UDID with someone you trust (a developer working on an app you're testing) is safe in itself. The UDID alone doesn't give anyone access to your messages, photos, contacts, or anything else on your device. It's just an identifier on a list of devices in Apple's Developer Portal.

Where you should be careful: don't post your UDID publicly (on Twitter, Reddit, GitHub issues, etc.) — once it's on the open web, anyone could ask Apple to register it on their developer account. Keep it private to the people who need it.

App On The Go's UDID lookup is also privacy-respecting: we hold the result just long enough to display it on this page, then automatically delete the lookup record within 24 hours. We never share UDIDs with anyone.

FAQ

UDID lookup, answered.

What is a UDID? +
A UDID (Unique Device Identifier) is a 40-character hexadecimal string that uniquely identifies an iPhone, iPad, or iPod touch. Apple developers ask for it to register your device for ad-hoc app distribution and TestFlight-style beta builds.
How do I find my iPhone UDID without iTunes? +
Open this page in Safari on the iPhone whose UDID you want, tap Find my UDID, and install the temporary profile in Settings. The 40-character UDID appears on the page within a few seconds. No iTunes, no Xcode, no Mac required.
How do I find my iPad UDID online? +
The same way as iPhone — open this page in Safari on the iPad, tap Find my UDID, and install the profile when iOS prompts. Works on every iPad model from iPad Air 2 onward, on iPadOS 12 through iPadOS 18.
Is finding my UDID online safe? +
Yes. The temporary profile only requests your device identifiers (UDID, model, iOS version, serial). It can't read your messages, contacts, photos, or anything else. iOS auto-removes the profile after the lookup completes.
Why does iOS say "Unverified Profile"? +
Our profile isn't code-signed with a paid Apple Developer ID, so iOS displays the standard warning for unsigned profiles. Every free UDID lookup tool shows the same warning. The profile is still scoped to read-only device-info access.
Do you store my UDID? +
Only briefly — long enough to display it on the page. Lookup data is deleted automatically within 24 hours. We never share UDIDs with anyone.
Can I find my UDID without a computer? +
Yes — that's exactly the point of this tool. Just your iPhone or iPad and Safari is all you need. No Mac, no iTunes, no Xcode, no Lightning cable.
What's the difference between UDID and serial number? +
Both identify the device uniquely, but they're used for different things. The serial number is on the back of the device and stamped in iOS Settings. The UDID is a longer 40-character hex string Apple uses internally for provisioning profiles.
What's the difference between UDID, IDFA, and IDFV? +
UDID is hardware-bound and never changes. IDFA (Identifier for Advertisers) and IDFV (Identifier for Vendor) are user-controllable identifiers that can be reset. Developers asking for a UDID for beta distribution want the hardware one.
What does my developer do with my UDID? +
They register it on Apple's Developer Portal under their team's Devices list, then re-sign the app build to include your UDID in its provisioning profile. After that, the app can install on your device.

Ship the build,
then find the UDID.

Got the UDID? Now share your .ipa with testers via App On The Go.

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