Ad preloading is an ad loading feature in GMA Next-Gen SDK that loads ads in the background and caches the ads before showing. To improve performance using ad preloading, disable custom caching and delegate that responsibility to GMA Next-Gen SDK. [Video](https://www.youtube.com/watch?v=gtCvIEGOwtA) Ad preloading in GMA Next-Gen SDK automates ad loading and caching. Ad preloading provides the following benefits: - **Reference management**: maintains references until ads are shown. - **Automatic reloading**: loads a new ad when one is retrieved from the cache. - **Managed retries**: loads a new ad when one fails to load. - **Expiration handling**: refreshes ads before expiring. - **Cache optimization**: optimizes the cache order to deliver the highest priority ad. ## Compare ad preloading and single load Use ad preloading as the default integration for full-screen ads in your app. If you have an existing app that uses single-load ad requests, see [Migrate to ad preloading](https://developers.google.com/admob/android/next-gen/migrate-to-preloading.md.txt). The following compares ad preloading and single load ad requests: ### Ad preloading Use ad preloading for the following advantages: - **Automated lifecycle management** : Delegate ad caching, expiration tracking, failed request retries, and ad refreshes to GMA Next-Gen SDK without writing or maintaining custom lifecycle code. When you get a preloaded ad from the cache to show, GMA Next-Gen SDK automatically loads a replacement ad. - **Ads ready at transition points** : Preload ads ahead of time to display ads when users move between levels or screens. To balance launch latency with session revenue, see [Reduce first impression latency](https://developers.google.com/admob/android/next-gen/reduce-first-impression-latency.md.txt#improve_performance_on_less_time-sensitive_impressions). - **Optimized ad selection** : Let GMA Next-Gen SDK store multiple ads per preload configuration and serve the highest-priority ad from the cache each time you show an ad. ### Single-load Use single-load ad requests only when you need direct control over individual ad requests, for example: - **Inbound mediation** : If you mediate GMA Next-Gen SDK through a third-party mediation platform, such as partner bidding, use single-load ad requests. For details, see [About partner bidding](https://support.google.com/admob/answer/12374519). Because the third-party mediation SDK manages waterfalls, caching, and refresh cycles, GMA Next-Gen SDK expects a single ad request for each adapter load call. - **Time-sensitive first impression requests** : If you need to show an ad at app launch with a specific targeting setup, such as a bidding-only mediation group with custom key-value targeting, use a single-load ad request for the first impression. For details, see [Reduce first impression latency](https://developers.google.com/admob/android/next-gen/reduce-first-impression-latency.md.txt#remove_waterfall_ad_sources_on_your_first_request). - **Custom ad requests** : If you set custom `AdRequest` parameters that change before each request, use single-load ad requests. Updating a `PreloadConfiguration` object restarts preloading and clears your cached ads. ### Compare ad lifecycle behaviors The following table compares how ad preloading and single-load handle ad lifecycle behaviors: | Behavior | Ad preloading | Single-load API | |---|---|---| | **Store ads** | Stores loaded ads in an internal cache until you call the `pollAd` method. | Your app must store the loaded ad object reference in a member variable until you show the ad. | | **Reload ads** | Automatically loads a replacement ad when you retrieve an ad from the cache. | Your app must manually call the `load` method after the user dismisses an ad or the ad fails to show. | | **Failed request retries** | Automatically retries failed requests using exponential backoff. | Requires custom retry logic to handle failed requests. | | **Expiration and refreshes** | Tracks ad expiration and automatically refreshes expired ads in the cache. | Your app must track expiration times and request an ad manually. | | **Cache optimization** | Stores multiple ads per preload configuration and serves the highest-priority ad first. | Loads one ad per request with no built-in queue or cache ordering. | ## Ad preloading lifecycle Ad preloading replaces manual ad loading calls with the following lifecycle steps: - **Start ad preloading** : Call the `start` method once per preload configuration. For implementation details, see [App open](https://developers.google.com/admob/android/next-gen/app-open.md.txt#start_ad_preloading), [Interstitial](https://developers.google.com/admob/android/next-gen/interstitial.md.txt#start_ad_preloading), [Rewarded](https://developers.google.com/admob/android/next-gen/rewarded.md.txt#start_ad_preloading), or [Rewarded interstitial](https://developers.google.com/admob/android/next-gen/rewarded-interstitial.md.txt#start_ad_preloading). - **Get and show the preloaded ad** : Call the `pollAd` method, and then call the `show` method. For implementation details, see [App open](https://developers.google.com/admob/android/next-gen/app-open.md.txt#get-the-ad), [Interstitial](https://developers.google.com/admob/android/next-gen/interstitial.md.txt#get-the-ad), [Rewarded](https://developers.google.com/admob/android/next-gen/rewarded.md.txt#get-the-ad), or [Rewarded interstitial](https://developers.google.com/admob/android/next-gen/rewarded-interstitial.md.txt#get-the-ad). - **Optional: Stop preloading ads** : Call the `destroy` or `destroyAll` method. For implementation details, see [App open](https://developers.google.com/admob/android/next-gen/app-open.md.txt#stop-preloading), [Interstitial](https://developers.google.com/admob/android/next-gen/interstitial.md.txt#stop-preloading), [Rewarded](https://developers.google.com/admob/android/next-gen/rewarded.md.txt#stop-preloading), or [Rewarded interstitial](https://developers.google.com/admob/android/next-gen/rewarded-interstitial.md.txt#stop-preloading). ### Preload cache limits Buffer size controls the number of preloaded ads held in memory for a preload configuration. By default, Google optimizes buffer size to balance memory consumption and ad serving latency. GMA Next-Gen SDK enforces an app-wide limit on the total number of preloaded ads across all ad units and preload IDs: - **Default app-wide limit** : GMA Next-Gen SDK holds a maximum of six preloaded ads in memory across all formats and preload IDs. - **Recommended buffer size**: We recommend keeping a buffer size of two for each preload ID. > [!NOTE] > **Note:** If your app can benefit from an increased app-wide limit, contact your account manager to request an increase. ## Next steps GMA Next-Gen SDK supports ad preloading for full-screen ad formats. Banner and native ad formats don't use ad preloading. Banner ads refresh automatically based on your ad unit configuration, and native ads use the `NativeAdLoader` class. Integrate ad preloading for your chosen ad format or optimize launch latency: - [App open](https://developers.google.com/admob/android/next-gen/app-open.md.txt) - [Interstitial](https://developers.google.com/admob/android/next-gen/interstitial.md.txt) - [Rewarded](https://developers.google.com/admob/android/next-gen/rewarded.md.txt) - [Rewarded interstitial](https://developers.google.com/admob/android/next-gen/rewarded-interstitial.md.txt) - [Migrate to ad preloading](https://developers.google.com/admob/android/next-gen/migrate-to-preloading.md.txt) - [Reduce first impression latency](https://developers.google.com/admob/android/next-gen/reduce-first-impression-latency.md.txt)