What ad blockers block
Modern ad blockers go far beyond ads. They block:
- Third-party ad pixels, Meta Pixel, Google Tag Manager, TikTok Pixel
- Analytics tags, Google Analytics, Mixpanel, Amplitude (when on third-party domains)
- A/B testing tags, Optimizely, VWO
- CDP collectors, Segment, Rudderstack (third-party endpoints)
- Heatmap and session-replay tools, Hotjar, FullStory
The decision is made by filter lists like EasyList (ads), EasyPrivacy (trackers), and the Disconnect.me list (referenced by Firefox ETP). If a domain is on the list, the browser request never goes out.
Penetration rates
Wildly variable by audience and geography. Rough 2026 benchmarks:
- General consumer audience: 15-25% blocker usage
- DTC e-commerce verticals: 25-40%
- Technical / B2B / developer audiences: 40-60%
- Privacy-conscious markets (Germany, Netherlands, Nordics): 30-50%
Even at the low end, missing one quarter of your conversion data is a problem. At the high end, your pixel-based tracking is reporting on a minority of actual events.
What ad blockers DON’T block
Ad blockers operate by intercepting browser HTTP requests. They can’t intercept:
- First-party requests to your own domain, your server-to-server calls are invisible to the browser extension
- Server-side CAPI / Conversions API calls, never touch the browser
- Backend integrations, Klaviyo subscriber syncs, BigQuery loads, etc.
This is why the modern resilient tracking stack moves the work off the browser entirely.
How to recover ad-blocker conversion data
Three patterns:
- Server-side first-party tracking, events fire from your server to the ad platform, bypassing the browser pixel entirely
- Same-domain pixel proxy, the pixel endpoint runs on a subdomain of YOUR site, not on
facebook.com. Ad blockers may still catch it via behavior heuristics, but the easy domain-list block fails. - CAPI / Conversions API, the server-to-server conversion forwarding path that ad blockers can’t see
A complete strategy usually combines all three: keep the pixel (for users without blockers, and for platform compatibility), add CAPI (for the conversions the pixel misses), and run server-side identity so the data has the context to be useful.
Common mistakes
- Pretending ad blockers aren’t a problem. They are, and in your target audience the rate is probably higher than the public average.
- Trying to circumvent blockers with anti-blocker tech. Aggressive evasion gets your domain added to filter lists. Server-side tracking is the durable solution.
- Reporting pixel-only ROAS as truth. It’s the floor, not the truth.
FAQ about Ad Blocker
What do ad blockers block?
Modern ad blockers block ad pixels, analytics tags, A/B testing scripts, heatmap tools, and CDP collectors, essentially every third-party tracking endpoint on common filter lists like EasyList and EasyPrivacy.
How many users have ad blockers?
Highly audience-dependent. Consumer audiences 15–25%, DTC e-commerce 25–40%, technical / B2B audiences 40–60%. In premium and privacy-conscious markets the rate climbs further.
How do I track ad-blocker users?
Server-side first-party tracking, fire events from your own server, server-to-server to ad platforms. Ad blockers can only intercept browser requests. They cannot see what happens on your backend.