What is the difference between GAID and IDFA?

Both are resettable advertising IDs. GAID is Android's, available unless the user deletes it. IDFA is Apple's, and since iOS 14.5 apps must ask permission through App Tracking Transparency before reading it, so most iOS users do not share it.

How do I reset or delete my advertising ID on Android?

Open Settings, go to Privacy or Google, then Ads, and choose to reset or delete the advertising ID. The exact menu names vary by phone maker and Android version.

Is the GAID personal data?

Regulators in the EU and elsewhere treat advertising IDs as personal data because they identify a device. You need a lawful basis, usually consent, to use them for advertising in those regions. See our consent entry for the basics.

Back to Glossary

Mobile & Push

GAID(Google Advertising ID)

A resettable, user-controllable identifier that Google Play services provides on Android devices for advertising, attribution and analytics.

Definition

The GAID (Google Advertising ID), also called AAID (Android Advertising ID), is a unique ID for advertising use that Google Play services makes available to Android apps. Unlike a hardware identifier, users can reset it at any time or delete it, in which case apps receive a string of zeros instead. Ad networks and mobile measurement partners use it to attribute installs, cap ad frequency and build audiences. Its iOS counterpart is the IDFA (Identifier for Advertisers), which apps can only read after the user agrees in Apple's App Tracking Transparency prompt.

Why It Matters

The GAID is still the main way Android ad campaigns are measured and targeted at the device level, which is a big reason Android attribution is more precise than iOS. It is also personal data under laws like GDPR, so collecting it brings consent and disclosure duties. For lifecycle marketers, the GAID matters mostly indirectly, through the attribution data and ad audiences built on it, rather than as an identifier to message people with.

How It Works

Apps request the ID through the Google Play services advertising ID API. Apps targeting Android 13 and later must declare the AD_ID permission in their manifest to read it. If the user has deleted their advertising ID in settings, the API returns zeros, and apps must respect that as an opt-out. Apps are expected to use the GAID only for advertising and analytics and not to link it with persistent identifiers without consent. The IDFV (identifier for vendor) on iOS is a separate ID shared only among one developer's apps and does not need the tracking prompt.

Example

How a mobile game uses identifiers:

GAID on Android: passed to its mobile measurement partner to attribute installs to ad campaigns.
IDFA on iOS: collected only for players who allow tracking in the App Tracking Transparency prompt.
IDFV on iOS and the game's own user ID: used for internal analytics and support.
Email address: used for account recovery and lifecycle emails after the player creates an account.

Best Practices

1Read the GAID only if an SDK you use actually needs it for advertising or attribution
2Declare the AD_ID permission if your app targets Android 13 or later and uses it
3Treat a zeroed ID as an opt-out and never try to replace it with another device identifier
4Disclose advertising ID use in the Play Console data safety form
5Use your own user IDs, not advertising IDs, for product analytics and messaging

Mobile Identifiers Compared

Identifier	Platform	Resettable	Needs permission	Typical use
GAID (AAID)	Android	Yes, or deletable	AD_ID manifest permission	Ads and attribution
IDFA	iOS	Yes	App Tracking Transparency prompt	Ads and attribution
IDFV	iOS	Changes when all the vendor's apps are removed	No	Analytics within one developer's apps
Push token	iOS, Android, web	Can rotate; not a permanent device identifier	Display permission varies by platform; token registration is separate	Push delivery