Line items

Traffic web interstitials

How to incorporate web interstitials to your web page

Web interstitials are full-page web ads and are an additional inventory and revenue source. You can monetize web pages with impactful ads while respecting Better Ads Standards.

To respect the user experience, web interstitials:

  • Have a clear exit option.
  • Have a configurable frequency cap—by default, a given publisher can show an ad to a user only once per hour per subdomain.
  • Match Google Search standards for avoiding intrusiveness.
You can serve interstitials for apps using the Google Mobile Ads SDK.
Web interstitial ads require access to local storage. For publishers integrated with the IAB Transparency and Consent Framework v2.2, this means that consent for Purpose 1 is required for web interstitial ads to function.

Get started

  1. Tagging
    1. Add the INTERSTITIAL GPT slot type to the <head> element of the web page.
    2. Display the ad slot as you would any other ad slot.
    See more tagging details, including how to prevent certain links from triggering the interstitial, in the developer documentation.
  2. Trafficking
    1. Create a new ad unit or use an existing one for the interstitial ad slot. Select the size 320x480, 300x250, and 336x280.
    2. Create line items:
      1. For reserved and programmatic direct inventories: Target inventory as normal. Creatives must have the size 320x480, 300x250, or 336x280. Note that you can target line items by Inventory format, with "Interstitial" as an option.
      2. For non-reserved inventory: Include the relevant ad unit in the Ad Exchange line item. Include the sizes 320x480, 300x250, or 336x280 in the associated placeholder creative. These fixed sizes are needed only for trafficking purposes on Ad Exchange line items. Ads served programmatically can be a range of sizes depending on the size of the viewport.
      3. For video out-stream ads (reserved and programmatic direct inventories): Target inventory as normal. Creatives must have the size 320x480, 300x250, or 336x280. Note that you can target line items by Inventory format, with "Interstitial" as an option.
    3. For web interstitials in private auctions:
      Don't select a size. The deal can't be limited to the web interstitial format by selecting a size(s) but it can, if required, be limited to the web interstitial format by other means, such as, using an ad slot specific key-value, or using a separate inventory unit.
  3. Reporting
    Use the "Inventory format" dimension and filter "Creative size (delivered) > is any of > Interstitial" to see how interstitials perform compared to other formats.

Demo interstitials

To demo the interstitial format, append #gamInterstitialDemo to a website page that already has some GPT tags. Clicking a navigation link on the page should trigger the format.


Web interstitials can be triggered when a user:

  • Navigates to a page 
  • Unhides a tab/window (for example, when they revisit a tab/window after going to another tab/window, revisit a tab/window after unlocking the device screen, or maximize a window after minimizing it) 
  • Clicks the browser's navigation bar (desktop only) 

Web interstitials respect the frequency cap set by the publisher, even if a user triggers multiple actions that can display an interstitial.

Opt in to triggers

To opt in to receive additional triggers:

  1. Sign in to Google Ad Manager.
  2. Click Inventory, then Network Settings.
  3. Under the "Web interstitial triggers" field, select which trigger to opt into.
  4. You can also opt into triggers by tagging your pages.

    This example shows how to opt into the unhide tab/window trigger:


    const interstitialSlot = googletag.defineOutOfPageSlot(
      // The publisher wants to enable the 'unhideWindow' trigger.
      interstitial: {
        triggers: {
          unhideWindow: true,

    This example shows how to opt into both the unhide page and navigation bar triggers:


    // Define a GPT managed web interstitial ad slot.
    const interstitialSlot = googletag.defineOutOfPageSlot(

    // Enable optional interstitial triggers.
    // Change this value to false to disable.
    const enableTriggers = true;

      interstitial: {
        triggers: {
          navBar: enableTriggers,
          unhideWindow: enableTriggers,

Frequency caps and interstitials

To ensure that users see a default of one ad per hour per subdomain, Ad Manager uses local storage to verify that a user has not seen a web interstitial in the past hour. Use of this format is subject to the EU user consent policy. If you don't obtain consent, web interstitials won't be requested.

You can use format frequency caps to change the frequency cap for web interstitials.

Ineligible links

Some links on a page may be considered ineligible to show interstitial ads. Interstitial ads won't be shown when a user clicks an ineligible link, for example, links to URLs without HTTP/HTTPS and links that open a new window.

You can prevent specific links from triggering GPT-managed web interstials by adding a data-google-interstitial="false" attribute to the anchor element or any ancestor of the anchor element.

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