How mobile app interstitials work

Interstitials are full-page ad units served between screens during mobile app navigation. They present a user with rich HTML5 experiences or “web apps” at natural app transition points such as launch, video pre-roll, or game level load. Interstitial ads:

  • Are perfect for brands: The large size presents an ideal canvas for storytelling, making them a highly attractive format for brand advertisers.
  • Are highly engaging: Because of their size, use of rich media, and attractiveness to premium brands, interstitials drive high user engagement. This, in turn, generates high clickthrough and conversion rates.
  • Are in demand: Interstitials are constantly cited as the most desirable ad format by both brand and performance mobile advertisers.
  • Increase ad diversity: Integrating new ad formats is one way publishers can deliver a diverse ad experience to their users, thus minimizing "banner blindness" and increasing overall ad engagement.

Watch related Publisher University training

For more detailed information and examples, please refer to the developer’s guide.

Benefits of interstitials on Ad Exchange

Ad Exchange mobile sellers can request interstitials from their apps directly or through Google Ad Manager by simply trafficking Ad Exchange code for the interstitial. This feature is available as an additional ad size and can easily be implemented on all publisher properties. Ad Exchange interstitials:

  • Provide strong revenue returns: Interstitials historically have higher CPMs than banner ads.
  • Use diverse demand sources: The Ad Exchange allows you to tap into interstitial demand from all the major DSPs and agency trading desks, as well as over two million advertisers through Google AdWords.
  • Provide creative variety: The Ad Exchange supports multiple creatives within the interstitial format, including full-page rich media units, dynamically created app promotion units, and standard banners against an opaque background. This variety drives up auction pressure, resulting in higher CPMs.

Get started with trafficking interstitials

When trafficking interstitials on Ad Exchange, please keep the following in mind:

  • Unlike static ad sizes, whose requests are based on a fixed box size, the size of interstitial requests depends on an interstitial format request as well as the screen size of the device requesting the ad.

    Here’s the process:

    1. Ad Exchange sends the width and height of the entire screen to the buyer as the requested size.
    2. The buyer can then respond with any size creative as long as it’s 50% of the screen width and 40% of the screen height.

    For example:

    1. Ad Exchange requests a 320x480 interstitial ad.
    2. An interstitial creative ranged from 160x192 to 320x480 can be returned from Ad Exchange.
    For trafficking purposes in Google Ad Manager, interstitials should be sized at either 1024x768 or 768x1024 for tablets, or 320x480 or 480x320 for mobile devices. Both Ad Exchange and Google Ad Manager use these four set sizes to denote interstitials. However, Ad Exchange will also use the actual screen size of the device to request ads from buyers.
  • Interstitials are not trafficked differently than other ad units. Publishers should treat an interstitial ad request like any other size. Keep in mind that interstitials should only be called for ad units that occupy the entire screen: in other words, a takeover.
  • The timing of a close option for interstitials depends on whether your interstitials are opted into video. If they are opted into video, some ads may have up to a 5-second delay before providing a close option. By policy, interstitials that don’t allow video will have an immediate close option. The Google Mobile Ads SDK will begin enforcing this more aggressively with releases of the Google Mobile Ads SDK: 7.21 or later for iOS, and 11.4 or later for Android.
  • To see how your interstitials are performing, select the Inventory sizes dimension type in the Query Tool. The report will display "Interstitial" when the ad call is an interstitial ad in a mobile device.
  • Only interstitials booked via direct campaigns in Google Ad Manager can be automatically closed. Interstitials served via dynamic allocation (e.g., Ad Exchange, AdSense, or Google AdMob) can only be dismissed by the user.
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