Ad Blocker Info — Ad-blocker detection

What is Ad Blocker Info?

The Ad Blocker Info add-on detects whether a visitor uses an ad-blocker (uBlock Origin, AdBlock Plus, etc.) and adds a X-DataNostro-AdBlocker-Detected header.

Why use Ad Blocker Info?

• Reporting: What % of visitors use an ad-blocker?
• A/B testing: Segment users with/without an ad-blocker.
• Monetization: Show a special message to users with an ad-blocker.
• Data quality: Understand the impact of ad-blockers on tracking.

How to activate

1. Go to Dashboard → Add-ons
2. Turn on the "Ad Blocker Info" toggle
3. The power-up automatically detects ad-blockers client-side
4. Detection works via a bait request

The added header

X-DataNostro-AdBlocker-Detected: true
# or
X-DataNostro-AdBlocker-Detected: false

How does detection work?

1. The Custom Loader contains a "bait" request to /ads.js (a typical path blocked by ad-blockers)
2. If the request fails → an ad-blocker is detected
3. The result is saved to the _dn_adb cookie
4. The cookie is carried into the X-DataNostro-AdBlocker-Detected header

Supported ad-blockers

• uBlock Origin (the most popular)
• AdBlock Plus
• AdGuard
• Ghostery
• Privacy Badger
• Brave Browser (built-in blocker)

Usage example in GTM

const hasAdBlocker = getRequestHeader('X-DataNostro-AdBlocker-Detected');
if (hasAdBlocker === 'true') {
  // Send custom dimension to GA4
  sendToAnalytics({
    ad_blocker_status: 'active'
  });
}

Statistics

Typically 25-40% of e-commerce visitors use an ad-blocker. On tech/privacy-focused sites it can be up to 60%+.