Interstitial Ads Best Practices

The Basics

Interstitial ads provide full-screen experiences, commonly incorporating rich media and video to offer a higher level of interactivity compared to banner ads. Creative assets are often large and take time to download. To ensure the best user experience, MoPub provides the ability to pre-cache creative assets prior to when the ad will be shown.

To help manage this added complexity, make use of the following MoPub SDK features:

  • iOS: use the variety of callbacks included within MPInterstitialAdControllerDelegate
  • Android: use the MoPubInterstitial object and its associated listener events

Best Practices

  • Use lazy loading: wait until the interstitial ad will be needed/used to load it.
    • Benefit: This will help avoid issues with time-outs and cancellation during the period when the ad is loaded on the device but not shown, and thus improve fill rate.
    • Benefit: DSPs will often optimize based on fill/clear rates and reallocate spend accordingly.
    • Beware: Some DSPs will use creative URLs, which expire after a certain period of time. This can lead to blank ads and discrepancies.
    • Beware: Make sure to allow enough time (up to 30 seconds) for the interstitial to load. Make use of MoPub’s provided event listeners.
  • Use event listeners within the application to help you figure out when to load and show the ad. (E.g. If an interstitial will show at the end of a game, load the interstitial when the user’s second-to-last life is used, rather than at the beginning of the game.)
    • Benefit: The probability of the impression being shown will increase as the time between load and show decreases.
  • Make sure to test callbacks diligently, as the MoPub SDK relies on functioning callbacks to work properly. Use breakpoints and logging to help with testing.


Close buttons are required to be functional and fully visible to ensure that the end user is able to dismiss the interstitial when needed.

MoPub provides the interstitial close button for all non-MRAID creatives:

  • Server-to-server
  • Marketplace
  • Direct-serve/backfill line items setup through the UI with an image creative

If the creative tag is a third party JS tag, it will depend on the creative type.

  • For MRAID creatives scheduled through the UI (with the MRAID box checked) or from MoPub Marketplace, MoPub will provide a 50×50 pixel “close zone” on the top right corner regardless of whether the close button is visible, per the IAB spec.
  • The interstitial close button is generally provided by the SDK. If the creative specifically requests to control the close functionality by calling the mraid.useCustomClose method, the close button will be provided by the creative.
  • If creative is not MRAID (just HTML) and MRAID box is not selected, the MoPub SDK will provide the close button.

MoPub does not provide the interstitial close button for:

  • Mediated third-party SDKs through MoPub, where the partner SDK has control over the close button and how the ad functions once they are showing the ad.

The MoPub close button is located in the following locations:

  • For iOS, the close button can be found in the GitHub iOS SDK Resources folder.
  • For Android, the close button is programmatically created via file for VAST, Rewarded Video and Native Video.
  • For Android, the close button is programmatically created via the file for other formats that support close buttons.


  1. Use Event listeners within the application to see if there’s an event in the app that will help trigger when an ad is shown and improve the probability of the impression being shown.
  2. If you’re implementing interstitials based on a user action (e.g. selecting an option, finishing a game level), avoid implementing an interstitial ad for every user action.
  3. Your app users will have the highest level of engagement with the first interstitial they see, and each subsequent interstitial will likely have a lower engagement rate.
  4. Avoid placements that could interrupt core elements of the app experience, keep a close eye on your analytics data to avoid diminishing returns.
  5. Using a mix of creative format types (i.e. MRAID, VAST, HTML) could allow you to increase frequency without hindering user experience.
  6. Interstitial ad units can (and should) be used in combination with other ad formats (i.e. banner, native).
  7. If your app sessions tend to be short (< 1 min) you may want to limit interstitials to static content. However, if your app has longer user sessions (2-3 mins), you should consider a mix of creative formats (i.e. static, MRAID, VAST).
  8. Monitor the success of each interstitial placement; if a placement isn’t generating revenue, move it somewhere else.
  9. Be patient, when interstitial placements first go live, it will take some lead time for demand to ramp up.
  10. Be wary of partners in your waterfall that are not failing over correctly, as this will cause a decrease in your fill rate.

Last updated November 05, 2019

TWITTER, MOPUB, and the Bird logo are trademarks of Twitter, Inc. or its affiliates. All third party logos and trademarks included are the property of their respective owners.

© 2020 MoPub (a division of Twitter, Inc.)