adUnitId

An adUnitId is a unique identifier assigned by an ad serving platform to a specific ad unit within an app or website. It is used by demand sources and reporting systems to distinguish one placement from another, enabling targeted delivery and performance tracking.

In practice, adUnitId is used by advertising SDKs to request ads from the platform. The value tells the platform which inventory to fill and how to attribute impressions, clicks, and revenue. Different platforms use different formats for these identifiers.

Examples of formats vary by platform. In Google AdMob, ad unit IDs typically appear as ca-app-pub-XXXXXXXXXXXXXXXX/NNNNNNNNN. In Google Ad Manager, the corresponding concept is often an ad unit path, such as /1234567/sports_banner, with SDKs sometimes referencing the path or a numeric ID depending on the integration. The exact format depends on the platform and the type of ad unit (banner, interstitial, rewarded, etc.).

Creation and management: Ad units are created in the platform’s console, assigned to an app or site, and then referenced in app code via the adUnitId. Each ad unit can be configured with supported ad formats, sizes, and targeting options. Proper organization of ad units helps with reporting and optimization.

Best practices: use test adUnitIds during development to avoid invalid traffic, replace them with production IDs before release, and avoid hard-coding IDs in publicly accessible codebases. Track performance by ad unit to identify higher-earning placements and optimize inventory.

Security and privacy: adUnitIds are configuration data rather than secrets, but they should be handled carefully to prevent unintended exposure and to maintain consistent behavior across environments.