What Changed
Like iPhone apps, early Android apps were often tracked with permanent identifiers: the device's Android ID, or hardware IDs such as the IMEI that couldn't be changed by the user.1
On October 31, 2013, Google introduced the Advertising ID with Google Play services 4.0, delivered through Google Play services rather than the operating system itself.2 It was a unique ID meant only for advertising, and users could reset it, which started them over with a new ID. A setting let users opt out of interest-based ads.3
Google then made it the condition for ads on Google Play. From August 1, 2014, the Play Store stopped accepting new apps and updates built with Google's older AdMob SDK, because it didn't use the Advertising ID and so broke Google Play's ad policy.4 That pushed ad SDKs away from permanent IDs and onto the resettable one.
The Advertising ID came with Google Play services, so it only exists on devices that have them. Devices without Google's services use other identifiers. Amazon's Fire tablets and TVs have their own Advertising ID, which Amazon requires apps to use over any other ID and which has its own opt-out, and some device makers provide an alternative called OAID.5,6 Where no advertising ID is available at all, attribution tools fall back to other device identifiers.6
Why It Mattered
The Advertising ID gave Android the same model Apple had adopted a year earlier with the IDFA: one shared, resettable identifier for ads across all apps on a device. Ad networks, attribution providers and app-install campaigns could work the same way on both platforms.
As on iOS at first, opting out was a signal rather than a block. Apps could still read the ID and were expected to respect the user's choice. Google tightened that in 2021: deleting the ID now returns a string of zeros.3 Apple had done the same in 2016.
Notes
- Bennett Cyphers, “How to Disable Ad ID Tracking on iOS and Android, and Why You Should Do It Now,” Electronic Frontier Foundation, May 11, 2022, https://www.eff.org/deeplinks/2022/05/how-disable-ad-id-tracking-ios-and-android-and-why-you-should-do-it-now. ↩
- “Google Play Services 4.0,” Android Developers Blog, October 31, 2013, https://android-developers.googleblog.com/2013/10/google-play-services-40.html. ↩
- “Advertising ID,” Play Console Help, Google, accessed October 11, 2026, https://support.google.com/googleplay/android-developer/answer/6048248. ab
- “Announcing Deprecation of the Standalone Android Google AdMob SDK,” Google Ads Developer Blog, February 11, 2014, https://ads-developers.googleblog.com/2014/02/since-joining-google-play-services-back.html. ↩
- “Advertising ID Policy,” Amazon Developer, accessed October 17, 2026, https://developer.amazon.com/docs/policy-center/advertising-id.html. ↩
- “Advertising Identifiers for Attribution,” Branch Help Center, accessed October 17, 2026, https://help.branch.io/v1/docs/advertising-identifiers-for-attribution. ab