unique device id ios swift with code examples

In today's world, mobile app development is exploding and there are billions of users who are interacting with apps every day. But as an app developer, one of the biggest challenges is to identify unique devices that are accessing your mobile app. This is where Unique Device ID comes in to play.

A Unique Device ID is a unique number that is assigned to each device when it is being manufactured. Apple’s iOS also provides developers with a tool to identify a device uniquely within their apps, it is known as UDID.

However, UDID was being misused by advertisers and some security issues prevailed. To tackle this issue, Apple has deprecated the use of UDID since iOS 5 and has now provided an alternative approach to identify devices uniquely.

In this article, we’ll discuss a few alternatives for UDID with a specific focus on one alternative approach, the Identifier for Advertising (IDFA), and show how to use it within an iOS application using Swift programming language.

  1. UUID

UUID stands for Universal Unique Identifier, it is a 128-bit number represented by a string of hexadecimal characters. UUID is randomly generated and is guaranteed to be unique among all devices in the world. UUID can also be used to uniquely identify an iOS device.

Here’s a code snippet that shows how to retrieve UUID in Swift:

if let uuid = UIDevice.current.identifierForVendor?.uuidString {
print("UUID: (uuid)")

  1. Advertising Identifier (IDFA)

IDFA is another way of identifying unique devices on iOS applications. It is similar to the UDID, however, the IDFA is not permanent and can be reset by the user. The IDFA can also be controlled by the user via the privacy settings. This makes IDFA a better choice for tracking and advertising purposes. It is commonly used by advertisers to track user activity and serve relevant ads.

Here's how to get IDFA in Swift:

let idfa = ASIdentifierManager.shared().advertisingIdentifier.uuidString
print("IDFA: (idfa)")

Note: The IDFA requires the user's permission to access it. So, the user must be asked for permission in order to use it within your application.

  1. Vendor ID

Vendor ID is a unique identifier for a device's vendor, which means that all devices of the same vendor will have the same vendor ID. This ID will not change even if the device is restored or a new app is installed.Therefore, Vendor ID can be used to track the same user across multiple apps if they were built by the same vendor.

Here's the Swift code snippet to get Vendor ID:

let vendorID = UIDevice.current.identifierForVendor?.uuidString
print("Vendor ID: (vendorID!)")

Note: Vendor ID is not meant to be used for advertising or tracking purposes, so it is recommended to use it solely for authentication purposes.


In this article, we have discussed the importance of unique device identification in iOS applications and how UDID was being misused, which resulted in its deprecation. We have also discussed three alternative approaches to UDID, UUID, IDFA, and Vendor ID. Among these approaches, we have focused on the IDFA and shown how to retrieve it using Swift programming language.

While it is important to retrieve a unique device identifier for various use cases, it is also important to respect user privacy and obtain their consent before accessing device identifiers. It is recommended to always get user permission through the device's privacy settings before accessing the device's unique identifier and use it ethically.

  1. UUID:

UUID is generated randomly and globally unique 128-bit identifier that is assigned to a device or an app at the time of its creation. This means that every UUID is unique for every device or app in the world. UUIDs are represented as a string of 32 hexadecimal digits separated by hyphens. UUIDs in iOS can be generated by using the identifierForVendor property of the UIDevice class. However, there are some limitations, if the app is deleted and then reinstalled, a new UUID will be generated for the device.

  1. Advertising Identifier (IDFA):

IDFA is generated by Apple and is assigned to every iOS device. It is a unique, non-permanent identifier that advertisers use to track user behavior and serve relevant ads. The IDFA is resettable and can be controlled by the user through setting their privacy preferences. The IDFA can be accessed in Swift using the ASIdentifierManager.shared() instance and the advertisingIdentifier property.

  1. Vendor ID:

The Vendor ID (VID) is a unique identifier assigned to iOS devices, which distinguishes devices of the same vendor. Apple generates the UUID and assigns it to an app or device when it is created and remain the same until the device or app is uninstalled. A Vendor ID is generated per Developer ID, that means all the apps from the same developer will have the same vendor ID. It can be accessed in Swift using the identifierForVendor property of the UIDevice class.

It is important to note that while unique device identification is important for various use cases, it is also important to respect user privacy, and obtain their consent before accessing device identifiers. If you are collecting this information as part of your app's functionality, it is a good idea to have a privacy policy in place that explicitly explains what information you are collecting and how you use it. This way, users have a clear understanding of how their data is being used and can make an informed decision about allowing access to their device's unique identifier.

In conclusion, whether you choose to use UUID, IDFA, or Vendor ID, it's important to consider the pros and cons of each. UUID is unique to each device, but can change if the app is deleted and reinstalled. IDFA can track user behavior across apps, but requires the user's permission. Vendor ID is unique to the developer but may not be appropriate for certain privacy concerns. Ultimately, it's important to consider your use-case and choose the identifier that best fits your needs while also respecting user privacy.

Popular questions

  1. What is a Unique Device ID?
  • A Unique Device ID is a unique identifier assigned to each mobile device when it is manufactured. It helps app developers to identify devices that are accessing their mobile apps.
  1. Is UDID still being used in iOS?
  • No, UDID has been deprecated since iOS 5 due to privacy concerns. It is now recommended to use alternative approaches to identify devices uniquely.
  1. What are some alternatives to UDID?
  • UUID, IDFA, and Vendor ID are some of the alternatives to UDID.
  1. How can you retrieve the IDFA in Swift?
  • The IDFA can be accessed in Swift using the ASIdentifierManager.shared() instance and the advertisingIdentifier property.
  1. Why is user privacy important when retrieving a device's unique identifier?
  • It is important to obtain the user's consent before accessing their device's unique identifier and to be transparent about the collection and use of this information. This helps to build trust with users and ensures that their privacy rights are respected. It is also important to comply with relevant privacy laws and regulations.


IDentifier (ID for short)

My passion for coding started with my very first program in Java. The feeling of manipulating code to produce a desired output ignited a deep love for using software to solve practical problems. For me, software engineering is like solving a puzzle, and I am fully engaged in the process. As a Senior Software Engineer at PayPal, I am dedicated to soaking up as much knowledge and experience as possible in order to perfect my craft. I am constantly seeking to improve my skills and to stay up-to-date with the latest trends and technologies in the field. I have experience working with a diverse range of programming languages, including Ruby on Rails, Java, Python, Spark, Scala, Javascript, and Typescript. Despite my broad experience, I know there is always more to learn, more problems to solve, and more to build. I am eagerly looking forward to the next challenge and am committed to using my skills to create impactful solutions.

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