Ad verification is the process of checking that a digital ad was delivered the way the advertiser paid for. It confirms the ad reached real people, in the intended location, next to suitable content, and in a position where it could be seen. Advertisers and agencies use independent verification tools to measure this and to avoid paying for impressions that fail these checks.

Because ad content and placement are often geo- and device-targeted, verification requires viewing ads from the actual locations and device types being audited, which is why proxies with IPs in those locations are useful for ad verification.

Verification checks typically cover more than just whether an ad displayed correctly. They also confirm it appeared in brand-safe surroundings and wasn't served to fraudulent or bot traffic.

Viewability Standards

A viewable impression is one that had a real chance to be seen on screen. Google's Active View metrics, built to Media Rating Council (MRC) industry standards, count an ad as viewable when:

  • Display ads: At least 50% of the ad's area is visible for at least 1 second.
  • Video ads: At least 50% of the ad's area is visible for at least 2 seconds.

An ad that loads but never scrolls into view counts as served, not viewable.

Pre-Bid vs. Post-Serve Checks

  • Pre-bid: The buying platform checks an impression before bidding, for example by looking up the page URL's brand safety rating. Traffic filtered at this stage is never bought.
  • Post-serve: Checks run after the impression or click happens. In Google's ad platforms, invalid traffic removed at this stage is credited back to the advertiser.
  • General invalid traffic (GIVT): Caught with lists of known spiders and robots and other routine checks.
  • Sophisticated invalid traffic (SIVT): Harder to identify, such as automated browsing or false representation. It needs deeper analysis or human review.