GAID (Google Advertising ID)

Google introduced the advertising ID so that apps would stop relying on permanent hardware identifiers for ads. The GAID, sometimes called AAID or Android Advertising ID, is a random string supplied by Google Play services. It identifies a device for advertising purposes only, and Google Play policy restricts how it can be used and linked to other identifiers.

How the GAID is used

• Install attribution. An attribution SDK reads the GAID in the app and matches it against the ad click or view that an ad network recorded for the same device.
• Postbacks and optimization. Networks receive install and in-app event results tied to the GAID and use them to find more users like your payers.
• Audience building. Lists of GAIDs can form custom audiences, exclusion lists and retargeting segments.
• Frequency capping and fraud checks. Seeing the same identifier across impressions helps limit repetition and spot suspicious patterns.

Reset, deletion and opt-out

Android gives users control over the ID in device settings. A user can reset it, which generates a new random value and breaks the link to past activity, or delete it. On recent Android versions, an app that requests the ID after the user has deleted it receives a string of zeros instead of a usable value. Apps targeting recent Android versions also have to declare a specific permission to read the ID at all.

In practice, this means a share of Android installs will always arrive without a usable ID. Attribution for those users falls back to other signals, such as referrer data from the Play Store, or goes unattributed. Plan reports and audience sizes with that gap in mind rather than assuming full coverage.

GAID compared with iOS identifiers

The GAID is available by default unless the user deletes it, while on iOS the IDFA is available only after the user grants permission through App Tracking Transparency, which is why Android still supports far more device-level attribution than iOS. IDFA, IDFV and ATT are covered in the adapty.io glossary.

Privacy Sandbox on Android

Google has proposed Privacy Sandbox on Android, a set of APIs intended to support interest-based advertising and attribution with less reliance on cross-app identifiers such as the GAID. Its scope and timeline have shifted since it was announced, so treat any plan built around it as provisional and check Google’s current documentation before changing your measurement setup.

What it means for subscription apps

For a subscription app running on both platforms, the GAID usually makes Android the easier platform to measure at the user level. You can connect a paid install to a trial, a first payment and renewals with fewer gaps than on iOS. That makes Android a useful reference point, but not a substitute: pricing, trial behavior and ad costs differ between platforms, so iOS channels such as Apple Ads still need their own revenue data per campaign and keyword.

Related terms: MMP, retargeting and SKAdNetwork have their own entries here; mobile attribution is covered in the adapty.io glossary.