Programmatic Advertising Resources - Next Millennium Media

What Is A Device ID? How Device ID Profiles Are Used In Ads

Written by Josh Isaac | 01/23/2025

Understanding where and how customers access your ads is marketing gold in digital advertising. Drilling down to a device ID profile gives advertisers fresh perspectives on achieving digital success.

Device IDs help advertisers know where users access ads, whether it’s on a tablet, smartphone, Kindle, iWatch, or any other handheld device. Capturing these Device IDs provides advertisers with valuable paths to improve and enhance targeting, grow sales, and deliver personalized experiences. 

In this article, we’ll explore:

  • What Is a Device ID?
  • What Is a Device ID Profile Used For in Digital Advertising?
  • Types of Device IDs
  • How To Find Your Device ID
  • How Does User Privacy Work With Advertisers Accessing Device ID?

 

What Is A Device ID?

A device ID is a random, unique string of numbers and characters assigned to a mobile device to identify it. A device ID is software-generated and used for digital interactions behind the scenes to validate user actions like downloading an app after clicking an ad. 

For example, a tablet user is browsing and clicks on an ad for an app and then installs it through an online app store like Google Play. When the app opens for the first time, a request is sent to the device’s operating system to retrieve its Device ID. Using a software development kit (SDK), this triggers a Device ID match that assigns ad credit for the app install.

Mobile device IDs enable advertisers to track user behavior based on device type, location, interests, and demographics, allowing for more precise targeting and segmentation. This opens doors to more personalized ads and enhanced relevancy for users.

 

Is The Device ID the Same as a Serial Number?

Comparing a Device ID to a serial number is like comparing a sled to a high-performance snowboard. Both are useful, but they serve very different purposes.

A Device ID is software-related, stored on the device, and accessible to apps. It’s used for tracking, analyzing app usage, and implementing targeted advertising strategies, among other uses. Meanwhile, a serial number is assigned by the manufacturer, much like a vehicle identification number (VIN) for a car, for inventory management or warranty purposes.

Advertisers and developers prioritize Device IDs over serial numbers because they unlock insights into user behavior, enabling more effective and successful digital marketing strategies.

What Is A Device ID Profile Used For In Digital Advertising?

Think of a Device ID Profile as a digital “folder” linked to a unique Device ID. This folder contains valuable data such as technical specifications, operating system, device model and type, screen resolution, browser version, and associated network details. Advertisers use this combined data to build user profiles, track behavior, and deliver personalized ads with deeper targeting insights. 

Importantly, the anonymous nature of Device IDs allows advertisers to customize user experiences without directly compromising privacy—though privacy concerns are a critical topic we'll address shortly.

One powerful use case is cross-device tracking, where advertisers analyze how users interact across multiple devices. For instance, a user might research a product on their tablet and later complete the purchase on their phone. Advertisers can use this information to refine messaging, minimize wasted impressions, and improve both ad targeting and retargeting strategies.

Types Of Device IDs

If you’re a “device purist,” you own either all Apple or all Android devices. That is true of most consumers, but no matter your preference, each device type has its unique Device ID system. Here are the types of IDs:

Apple's IDFA

  • Apple devices have an Identifier for Advertisers (IDFA), which is a privacy-focused, resettable identifier used specifically for advertising purposes meaning users can control whether apps can access their IDFA. 
  • Advertisers use the IDFA to track user interactions with ads, such as clicks and purchases, as well as using the data to create personalized ads and optimize campaigns. 
  • The IDFA is an all-uppercase string of letters and numbers that is split into a set of eight digits and then three sets of four digits. It looks like this: AB1234CD-E123-12FG-J123

Android's GAID 

  • Google Advertising ID (GAID) is a unique identifier for Android devices that advertisers use to track user activity. It's also known as the Android advertising ID. 
  • GAIDs are used to link anonymous app installations or purchases to specific users, create customer profiles that help advertisers understand their audiences, and track activity, such as targeting, frequency capping, and conversion attribution.
  • Google intends to deprecate the GAID, but does not plan to make any substantial changes until at least 2024

IMEI

  • The International Mobile Equipment Identity (IMEI)) assigns this unique 15-digit number to devices; every mobile phone in the world has one. 
  • GSM networks use the IMEI number to identify valid devices, and can stop a stolen phone from accessing the network and is also used for network registration, security, and more.

Users can opt in or out of sharing their Device ID with app developers and advertisers, giving them control over how their data is utilized.

How To Find Your Device ID

Finding your Device ID and other profile data is straightforward and only takes a few swipes, whether you’re using a smartphone or tablet. While operating systems differ slightly, the process is similar across devices. Users may need this information for customer service inquiries, troubleshooting system errors, or enabling specific features.

Reasons you may want to locate your Device ID:

  • Accessing device management features
  • Updating privacy settings
  • Enhancing device security
  • Tracking lost or stolen devices
  • Enabling app-specific features

However, privacy concerns remain a top priority for users, with 67% expressing concerns about data security. Understanding how to locate and manage your Device ID can help you take control of your privacy settings.

How To Find Your Android Device ID

For Android phones or tablets, follow these steps:

  1. Go to Settings.
  2. Select About phone or About device.
  3. Look for the Android Device ID or IMEI number.
  4. Additional details like your model name, number, and serial number are also listed here.

Privacy restrictions limit how third-party apps access Device IDs. Android requires app developers to seek user consent for accessing private information (e.g., calendars, photos, location). Users can review privacy policies and permissions in the Google Play Store’s Data Safety section before downloading apps.

How To Find Your iPhone Device ID

For Apple devices (iPhone, iPad, or iWatch):

  1. Open Settings
  2. Navigate to General and select About
  3. Find your Device ID, IMEI/MEID, or ICCID number listed here

To locate your iWatch Device ID through an iPhone:

  1. Open the Apple Watch app
  2. Go to the My Watch tab
  3. Select General, then About, to view the Device ID

Apple also emphasizes privacy with its App Tracking Transparency feature, which requires app developers to seek user consent for tracking activities. This gives users insight into what information apps want to access (e.g., photos, contacts, location) and allows them to manage permissions in their device settings. Apple’s rigorous app vetting process ensures apps meet its high privacy standards before being listed on the App Store.

How Does User Privacy Work With Advertisers Accessing Device IDs?

Device IDs strike a balance between providing advertisers with valuable insights and ensuring user anonymity. These unique identifiers enable advertisers to deliver personalized, relevant ads without accessing sensitive personal information. Thanks to privacy-first frameworks like the General Data Protection Regulation (GDPR) and the California Consumer Privacy Act (CCPA), users have greater control over how their data is used. Advertisers now work within these boundaries to create a more transparent and user-friendly ad ecosystem.

Rather than relying on outdated tracking methods, advertisers are embracing innovative strategies like leveraging first-party and second-party data collected directly from trusted publisher and brand sources. This approach not only respects user privacy but also enhances campaign effectiveness by focusing on high-quality data.

By working with programmatic advertising partners skilled in navigating these regulations, advertisers can continue reaching their audience with precision while fostering trust and compliance. This shift is driving the future of digital advertising, offering a win-win for both businesses and consumers.

Next Millennium Drives Advertiser Success Through Programmatic Advertising

Navigating evolving privacy regulations requires advertisers to stay agile and collaborate with the right ad partners. That’s why so many advertisers trust Next Millennium to maintain strong ad revenue, even amid industry changes. By partnering with us, advertisers gain exclusive access to premium publisher inventory, including first-party data and high-demand inventory not available on open exchanges. This means more engagement and better reach for every advertising dollar.

Take your campaign performance to the next level—we consistently deliver results that outperform industry benchmarks. For example, our campaigns have achieved:

  • 4X Google’s click-through rate (CTR) benchmark
  • 15%  increase in brand engagement
  • 90% viewability rate, compared to the IAB standard of 50%

With proven strategies and transformative ad solutions, Next Millennium helps advertisers exceed their revenue goals.