Free tool
Anti-Adblock Wall Detector
Check whether a site runs ad block detection, and see the specific evidence rather than a yes or no.
How detection actually works
A page cannot ask your browser whether an extension is installed. So it sets a trap instead. The
most common method is bait: the page includes an element with a class name that every filter
list hides, such as adsbox, then measures it a moment later. If the element has
zero height, something hid it, and that something is an ad blocker.
A second method loads a script from a path filter lists block, such as /ads.js. If
the script fails to load, a blocker cancelled it. A third, which this scanner weights heavily,
ships stylesheet rules keyed on a class the detector toggles, so the page silently restyles
itself once a blocker is found. Rules of that shape exist for exactly one reason.
Reading the confidence level
| Level | What it means |
|---|---|
| Detected | A named anti-adblock vendor is present, or two independent conclusive signals |
| Likely | One conclusive signal, such as adblock-conditional styling or a detection library |
| Weak signal | Something resembling detection, but ambiguous on its own |
| None found | Nothing detectable in the served HTML, which does not rule out runtime detection |
Why publishers do it
It is worth being fair about this. Advertising funds a large share of what is free on the web, and a publisher watching a significant portion of its audience consume content without contributing revenue has a real problem, not an imaginary one. Detection walls are a blunt response to it.
The counter-argument is equally real: ad blocking became mainstream because advertising became genuinely hostile, with pop-unders, autoplay video, trackers numbering in the dozens per page, and ad networks repeatedly used to deliver malware. We covered that last point in how ad infrastructure carries malware. Most people did not install a blocker to avoid supporting journalism; they installed it because the pages had become unusable.
What we would suggest
If a site you rely on asks you to turn off your blocker, whitelisting it is a reasonable thing to do, and our whitelist guide shows how. If you would rather not, most publishers running a wall also sell an ad-free subscription, which supports them more directly than the advertising would have.
What we would not recommend is an arms race of counter-detection scripts. They break constantly, they frequently break the page along with the wall, and they turn a straightforward decision into an ongoing maintenance problem.
Frequently asked questions
How can I tell if a site blocks ad blockers?
Enter its address above. The scanner looks for named detection libraries, decoy elements planted to be caught by filter lists, and stylesheet rules that only make sense if the page restyles itself once a blocker is found.
Is it legal for a site to detect my ad blocker?
Detecting one is generally permitted. How it is done can matter: European regulators have taken the position that reading information from a visitor’s device to perform the detection can require consent under the ePrivacy directive. That argument is still being tested and the position differs between member states.
Why does a site I know has a wall show no detection?
Because detection is often injected at runtime by a tag manager rather than written into the page source. This scan reads the HTML the server returns, so it proves presence rather than absence. A negative result is much weaker evidence than a positive one.
What should I do when a site blocks me?
Decide whether you want to support it. If you do, whitelisting the site is the honest option and takes two clicks. If you do not, most publishers with a wall also offer a paid ad-free tier, and there is usually an alternative source for the same information.