> [!NOTE] > **Note:** Key-value segmentation is available only for AdMob Pro users. For details, reach out to your Google account manager. Key-value segmentation lets you define custom targeting to segment users through an ad request. For details on key-value segmentation, such as adding a key-value pair in the AdMob UI, see [Add key-value segmentation to a mediation group](https://support.google.com/admob/answer/14916631). This page guides you through implementing key-value segmentation when configuring an ad request using GMA Next-Gen SDK. ## Before you begin To set up key-value segmentation in your app, you must first [add key-value segmentation to a mediation group](https://support.google.com/admob/answer/14916631). ## Attach key-value pairs to an ad request After setting up your custom key-value pairs in the AdMob UI, attach the pairs to an ad request in your application. To attach the key-value pairs to an ad request, call [`putCustomTargeting()`](https://developers.google.com/admob/android/next-gen/reference/com/google/android/libraries/ads/mobile/sdk/common/AdRequest.Builder.md.txt#putCustomTargeting(kotlin.String,kotlin.String)) with the key and value. The following example segments users by duration in an app: ### Kotlin ```kotlin val daysInApp = 1 val request = AdRequest.Builder("AD_UNIT_ID") .putCustomTargeting("USER_DURATION", if (daysInApp < 3) "NEW" else "MATURE") .build() ``` ### Java ```java int daysInApp = 1; AdRequest request = new AdRequest.Builder("AD_UNIT_ID") .putCustomTargeting("USER_DURATION", (daysInApp < 3) ? "NEW" : "MATURE") .build(); ``` ## Test the key-value segmentation setup To test your implementation on custom key-value pairs, send an ad request and check the [response info](https://developers.google.com/admob/android/next-gen/response-info.md.txt#response_info) object. Verify that the value of the `mediation_group_name` field matches your expected mediation group name. The following example verifies a mediation group name in the ad response: ```json { "Response ID": "r6_DZtitA8Gi2OMPyKeksAI", ... "Response Extras": { "mediation_group_name": "Mediation group for new users" } } ```