Reverse AdSense Lookup

Sites run by the same publisher usually share one AdSense account, and that account's ca-pub-XXXXXXXXXXXXXXXX publisher ID sits in plain text in the ad code of every page showing its ads. A reverse AdSense lookup searches the web's source for that ID, so one string reveals the whole network, the standard technique for connecting "independent" sites to a single operator, mapping a competitor's portfolio, or documenting made-for-advertising networks.

The footprints

A specific account: the exact ca-pub-… ID you're investigating, the 16-digit ID is unique to one AdSense account.
All AdSense sites: adsbygoogle.js, the ad library itself. See websites using AdSense.
Any publisher ID (regex): ca-pub-[0-9]{16}, every page embedding some AdSense publisher ID.

A worked example

Say you're on a site whose operator you want to map. View its source and copy the ID from the ad snippet, it looks like data-ad-client="ca-pub-1234567890123456" (older installs set it as the google_ad_client variable instead). Searching that exact string returns every indexed domain carrying the same account: often a handful of sibling content sites you'd never connect from branding alone. For scale, the generic library footprint adsbygoogle.js matches 2,055,724 domains in the August 2026 index, a single ca-pub- ID typically narrows that to a few.

Step by step

Get the ID. View the source of the starting site and search its text for ca-pub-; copy the full 16-digit ID.
Search it. Paste the ID into the search box as an exact string.
Verify each hit. Open the result to see the full page source with the match highlighted; confirm the ID sits in live ad code, not quoted text.
Pivot. Note the other IDs in each confirmed site's source, Analytics G-/UA- IDs, a Meta Pixel, a GTM- container, and search those too to extend the map.
Export. Export the confirmed domains as CSV for your report or monitoring list.

False positives and how to verify

A matched ID is strong evidence but not proof of common ownership. Rule out three cases: quoted IDs, blog posts, forum threads, and tutorials that mention an ID in text rather than ad code; scraped or mirrored pages that copy another site's HTML wholesale, ads included; and managed monetization, some ad-management services run their own AdSense account across client sites, so unrelated sites can legitimately share an ID. The check is the same each time: open the full source and read the context, real ad code loads adsbygoogle.js and sets the ID as data-ad-client, and treat ownership as confirmed only when a second shared signal (an Analytics ID, a pixel, WHOIS, hosting) corroborates it.

Related fingerprints

The same pivot works on any per-account ID embedded in source: Google Analytics IDs, Meta Pixel IDs, Google Tag Manager containers (GTM), and affiliate tags. The general technique, chaining shared IDs across a network, is covered in connecting domains by a shared tracking ID.

Search AdSense sites → AdSense results →

Frequently asked questions

Where do I find a site's AdSense publisher ID?

View the page source in your browser and search the text for ca-pub-. The full ID is 16 digits, usually set as data-ad-client in the ad snippet or as the google_ad_client variable on older installs.

Why does an ID search return sites that clearly aren't the same owner?

Usually one of three reasons: the page quotes the ID in article text rather than ad code, the page is a scrape or mirror of another site, or an ad-management service runs its own AdSense account across many client sites. Open each result's full source and look for a second shared signal before concluding common ownership.

Can a site hide its AdSense ID?

The ID has to reach the browser for ads to serve, but consent banners and lazy tag loading can keep it out of the initial HTML that a crawler stores. So a match is reliable evidence, while absence of a match is not evidence of absence.

How fresh are the results?

The index is rebuilt monthly from fresh crawls, so results reflect each site's homepage as of the last build. An ID removed from a site recently can still appear until the next rebuild.