Render an end cap for a mobile video ad

An end cap renders a static, clickable creative on completion of your video ad

You can implement an optional mobile video "end cap" to render a static, clickable creative which appears on completion of your video ad. Mobile video creatives using an end cap are accepted on all mobile app interstitial video inventory.

Use the EndCapSupport parameter under the video message to determine if a bid request supports end caps:

enum EndCapSupport {
   END_CAP_NOT_ENABLED = 0; // Companion ad won't be rendered as end cap.
   END_CAP_OPTIONAL = 1; // Eligible companion banner may be rendered as end cap.
optional EndCapSupport end_cap_support = 13 [default = END_CAP_NOT_ENABLED];

All details, specifications, and certification requirements for mobile video inventory, including in-app and mobile web, apply to creatives using an end cap. At this time, only mobile app interstitial video supports end caps.

Learn more about mobile video inventory.

Implement an end cap on a mobile video creative

The VAST template provides an option to include one or multiple companion banners using the <Companion> node in the XML. End cap implementation requires only that you traffic the companion asset with your video ad.

See a sample VAST response

   <Companion width="1024" height="768">
      <StaticResource creativeType="image/jpeg">
         <![CDATA[ https://...your-1024x768-image.jpeg ]]>
      <Tracking event="creativeView">
         <![CDATA[ ]]>
         <![CDATA[ ]]>
   <Companion width="300" height="250">
      <StaticResource creativeType="image/jpeg">
         <![CDATA[ http://...your-300x250-image.jpeg ]]>
      <Tracking event="creativeView">
         <![CDATA[ ]]>
         <![CDATA[ ]]>


The following resource types are allowed for the <Companion></Companion> node:

  • StaticResource: URI to a static file

Some publishers are enabled to use these additional resource types through reservations and deals: *

  • IFrameResource: URI source for an iframe to display the companion element
  • HTMLResource

* Contact your account manager for more information about using these resource types.

The end cap is a static creative, so only image resource types (static GIF, JPG, PNG) trigger the functionality.

Bidders can choose to return one or more companions in all of their video bid responses. In the event that end caps are not supported, the video will still be shown, and the companion banner will simply be ignored.

Since mobile app interstitial video inventory on Authorized Buyers accepts creatives using an end cap by default, you are not required to make any changes to your pretargeting configurations. Inventory forecasting is also unaffected.

Creative rendering

End caps are centered in the viewable area of the video ad slot. If more than one eligible companion banner exists in your VAST response, the companion of the largest area that is smaller than the screen size will render. You may want to include multiple companion banners in your bid response to account for different possible screen sizes.

If the orientation of the ad is portrait, the ad width cannot be less than 20% of the slot width and the ad height cannot be less than 10% of the slot height. If the orientation of the ad is landscape, the ad width cannot be less than 10% of the slot width and the ad height cannot be less than 20% of the slot height.

If included, an end cap stays on the screen until the user dismisses the video.

Users retain the option to "skip" and exit the end cap without clicking through. If the user skips the video ad during video play, Authorized Buyers will not render an end cap.

Click and impression tracking

Your end cap creative clicks through to the clickthrough URL defined in your VAST response. You can set a custom clickthrough URL for your companion creative using the CompanionClickThrough field of the companion node. You can also set a custom impression tracker for the companion using the <Tracking event="creativeView"> node.

Do not implement any sort of click tracking URL into the <Clickthrough> VAST node.

You should set up click tracking with the end cap tracking event only, and use the <CompanionClickThrough> for URLs that click through to the app store, or a specific page or redirect.

Learn more about the requirements to serve video ad units (VAST).

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