Pop-under
An ad format that opens a full page behind the user’s active browser window.
What is pop-under?
A pop-under is a performance ad format in which a full advertiser page opens in a new browser window or tab behind the one the user is viewing, usually triggered by a click on the publisher’s page. Because the ad page is not seen until the user finishes with the current window, it is less intrusive in the moment than a pop-up, although it still interrupts the browsing experience. Pop-under traffic is typically bought on CPM or CPA terms in large volumes and is common in affiliate and direct-response campaigns. Browsers, ad blockers and many publishers restrict it, so quality and policy controls are central to buying it well.
How pop-under works
The page loads in a new window beneath the current one and is seen when the user closes or moves it.
- A publisher places a pop-under script on its pages, often limited to one trigger per user session.
- When a user clicks on the page, a new window or tab opens behind the current one.
- The window loads the winning advertiser’s landing page directly, with no banner creative.
- The advertiser tracks visits and conversions to compare traffic sources and adjust bids.
Why it matters
It is a high-volume, low-cost performance format. It needs strict quality controls and is not suitable for every brand.
For advertisers
It can deliver large volumes of landing-page visits at low cost, suiting offers that convert on a full page.
For publishers
It can add revenue on high-traffic pages, but at the cost of user experience if used too frequently.
Practical example
A user closes the browser tab and finds an offer page open behind it.
Key considerations
- Frequency limits per user are important to avoid irritating visitors and harming the publisher’s reputation.
- Invalid traffic and accidental triggers are common risks, so source-level filtering and conversion tracking are needed.
- Many brand advertisers and some ad networks do not allow the format, so it is mainly used for performance offers.
More Performance Advertising terms
Frequently asked questions
What is the difference between a pop-under and a pop-up?
A pop-up opens in front of the current window and demands attention immediately, while a pop-under opens behind it and is seen later.
Do browsers block pop-unders?
Many browsers and ad blockers restrict windows that open without user action, so pop-unders usually rely on a click to trigger.
How is pop-under traffic usually bought?
Mostly on CPM or CPA terms, with campaigns optimised by blocking sources that do not convert.