Not checking whether the slot came back empty
GPT returns null when the page does not support an interstitial. Your code needs to check this before using the slot.
Implementation guide
Ad Manager web interstitial
Web interstitials
A full-page Ad Manager ad that GPT shows on page change and other triggers, with a clear exit and a frequency cap.
Desktop
Mobile
Understand it in 1 minute
What an Ad Manager web interstitial is
The web interstitial is a full-page Google Ad Manager ad. It appears at moments of pause, such as when the person clicks a link to go to another page of the site. Think of a soap opera break: the story stops for a moment, the commercial comes in and then the story continues. The person does not lose what they were reading, because the ad comes in during the move from one page to another.
GPT takes care of everything. It is the Google Publisher Tag, the Google code that requests and shows ads on the site. You just request an interstitial type slot, which is the ad space. GPT creates its own little box, picks the right moment and shows the ad. The trigger that is always on is the click on a link. There are others: returning to the site's tab, clicking the browser's navigation bar on desktop, reaching the end of the article, staying still for 30 seconds and then moving, and using the back button. They can be turned on in the network settings or in the code.
Google says the interstitial was made to follow the Better Ads Standards and comes with three protections for visitors: a clear exit, a frequency cap you can adjust and respect for Google Search's rules on intrusive ads. The default cap is 1 ad every 10 minutes for each person, and it can go down to 1 every 1 minute. Even when several triggers happen, the cap is respected.
It fits sites where people go through several pages. One important detail: the interstitial uses the browser's local storage to control frequency. Those who use the IAB TCF, a consent standard used in Europe, need consent for Purpose 1. Since November 4, 2024, people who did not give consent for local storage can also see the ad, unless you require that access with a code option.
Step by step
How to implement
- Create the ad unitUse the sizes 320x480, 300x250 and 336x280. In programmatic, these sizes are only for setup, because the ad can change size depending on the screen.
- Put the interstitial slot in the headIn GPT, define an out-of-page slot of the interstitial type and display it like any other slot. Check that it did not come back empty.
- Set up the line itemsIn reservations and programmatic direct, use creatives in these sizes and, if you want, target by the interstitial inventory format. In Ad Exchange, include the ad unit and a markup creative in one of the sizes.
- Choose the triggersClick Inventory and Network settings and adjust Web interstitial triggers. You can also turn on triggers in the code, as in the example.
- Adjust the frequencyThe default cap is 1 every 10 minutes. It can be changed in the network or in the ad unit, down to 1 every 1 minute.
- Protect links and testPut the exclusion attribute on the menu links. To test, add the demo code to the end of the page address and click a link.
Implemented example
The code and how it looks on screen
<!-- No head -->
<script async
src="https://securepubads.g.doubleclick.net/tag/js/gpt.js"
crossorigin="anonymous"></script>
<script>
window.googletag = window.googletag || { cmd: [] };
googletag.cmd.push(() => {
const interstitialSlot = googletag.defineOutOfPageSlot(
"/1234567/exemplo",
googletag.enums.OutOfPageFormat.INTERSTITIAL,
);
// Volta null se a página ou o aparelho não aceitar intersticial
if (interstitialSlot) {
interstitialSlot.addService(googletag.pubads()).setConfig({
interstitial: {
// Acionadores opcionais (o clique em link já vem ligado)
triggers: { navBar: true, unhideWindow: true },
},
});
}
googletag.enableServices();
if (interstitialSlot) {
googletag.display(interstitialSlot);
}
});
</script>
<!-- Link que nunca chama o intersticial (por exemplo, no menu) -->
<a href="https://www.exemplo.com/"
data-google-interstitial="false">Início</a>
<!-- Teste: acrescente #gamInterstitialDemo no fim do endereço -->
<!-- e depois clique num link -->
<!-- Teste de acionador (modelo da ajuda do Ad Manager): -->
<!-- #gamInterstitialTriggerDemo={navigationBar, pageUnhide, -->
<!-- inactivity, endOfArticle, backward} -->What Google recommends
Do and don't
Allowed
- Turn on the optional triggers in the dashboard, under Network settings, or in the code with the slot configuration.
- Change the frequency cap in the network or in the ad unit, down to 1 ad every 1 minute.
- Prevent specific links from triggering the interstitial by putting the attribute on the link or on an element above it.
- Sell in reservations, programmatic direct, Ad Exchange and private auction; in private auction, without choosing a size, limiting the deal by key-value or a separate ad unit.
- Serve non-in-stream video in reservations and programmatic direct, with the same sizes.
- Compare performance in the inventory format dimension, where it appears as interstitials.
Not allowed
- Do not request an interstitial on pages where you do not want it to appear.
- Do not run GPT inside an iframe: the interstitial only works with GPT in the main window.
- Do not use fixed widths and heights on mobile pages: use the viewport tag or avoid fixed sizes.
- Do not expect an interstitial on links that open a new window or that do not use http or https: these links never trigger the ad.
- Do not confuse it with the app interstitial: in an app, the format is a different product, served by the Google Mobile Ads SDK.
Tips
To do it right
- The default cap applies per person and per subdomain: 1 impression every 10 minutes.
- The link click is always on. The click triggers on the navigation bar and on going back to the tab come turned off and can be turned on.
- With single request architecture (SRA), make the first display call only after the page's fixed elements exist.
- In reports, the total ad requests does not count requests with no ad, so it can be lower than Ad Exchange requests.
Watch out
Common errors
Forgetting consent
The interstitial uses local storage. With TCF, without consent for Purpose 1, it may not work as expected.
Menu without exclusion
Without the exclusion attribute, every click on the menu can trigger the ad. Google recommends the exclusion precisely for navigation elements.
Creative in the wrong size
For reservations, use creatives of 320x480, 300x250 or 336x280, which are the interstitial ad unit sizes.
Frequently asked questions
Can the person close the interstitial?
Yes. The format has a clear exit, and the person can also close it with the browser's back button.
How many times does it appear?
By default, at most once every 10 minutes for each person. You can change it down to once every 1 minute.
Do I need to create a div?
No. The interstitial creates its own little box.
Is it the same as the AdSense vignette?
Both are full-page and appear between pages, but the vignette is from AdSense, in Auto ads, and the web interstitial is from Ad Manager, through GPT.
Library
Official Google source
Everything on this page follows Google's official documentation. Read it straight from the source:
Does your site use this format the right way?
The audit reads the site as a visitor would, without clicking anything, and shows what to fix.