What Is an Interstitial Popup? Mobile and SEO Risks

Whole Screen vs. Part of It

"Interstitial" means "in between." It first meant a page, often an ad, shown before or after the one you asked for. Now it's also a type of pop-up that fills the screen.

Google splits pop-ups by size. An interstitial covers the whole page, while a dialog covers only part, like a corner box or bottom bar. It works like a full-screen modal overlay that locks the page until you close it.

What It Hides on a Product Page

Stores like them because they get seen. But they also cover the product the shopper came to look at. Closing it first is a kind of buying friction. On a phone, a box that looks small on a laptop can fill the screen.

Example: A shopper searches "linen duvet cover" on her phone and taps a store's result. Two seconds later, a full-screen box offers 10% off for her email and hides the photo, price and Add to Cart button. The close X is small and pale, up in a corner.

She came for the price. Now she has to find the X or hand over her email, and the back button is one tap away. A slim bottom bar would let her see the price first and decide on the signup later.

What Google Says About Full-Screen Popups

In January 2017, Google added a mobile ranking signal for this. Pages whose content is hard to reach right after a search click may rank lower. Google said it's just one of hundreds of signals, so a strong page can still rank well. Its current guide suggests small banners instead.

Google exempts interstitials the law requires, like cookie notices or the age check a wine store may need.

Interstitials on a Shopify Store

On Shopify, full-screen popups usually come from apps, such as email, discount or age-check tools. Many also offer smaller layouts, like a box or bar.

Some interstitials open on exit intent, when a shopper seems about to leave. Our guide to exit-intent popups and their alternatives explains why they struggle on phones and what to show instead. Growth Suite, our app, shows offer details and a countdown timer on product and cart pages. The timer shrinks to a small icon after 1.5 seconds.

A Close Button Isn't Enough

One of Google's own bad examples was an interstitial you must dismiss to reach the main content. So a clear X isn't the fix. How much screen it covers matters more.