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Sometimes the conversion you care about happens after visitors leave your landing page—like completing a purchase on your main website or signing up in your app. External goals let you track these conversions and attribute them back to your landing page variants.

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How external tracking works

  1. A visitor lands on your Blox landing page
  2. Blox sets cookies with the visitor’s ID, session, and variant
  3. The visitor clicks through to your website
  4. Your website triggers the external conversion
  5. The conversion is attributed to the original landing page variant
This connection allows you to measure which landing page variant drives the most downstream conversions.

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Setting up external goals

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Step 1: Create the goal

  1. Open your brand settings
  2. Navigate to the Goals section
  3. Click Create goal
  4. Select External as the goal type
  5. Enter a name (e.g., “Purchase completed”)
  6. Enter an event name (e.g., “purchase”)
  7. Save the goal

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Step 2: Get the tracking code

After saving, Blox provides a tracking code snippet. It looks like this: 
<script src="https://blox.page/track.js" data-brand="your-brand-slug"></script>
<script>
  blox('track', 'purchase');
</script>

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Step 3: Add to your website

Add the tracking script to the page where conversions happen (e.g., your order confirmation page):
  1. Copy the script snippet
  2. Add it to your confirmation page’s HTML
  3. Deploy your website changes
The script automatically reads the visitor’s Blox cookies and sends the conversion.

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Tracking with values

You can include additional data with your conversion: 
blox('track', 'purchase', { value: 99.99 });
Or with more details: 
blox('track', 'purchase', {
  value: 99.99,
  order_id: '12345',
  product: 'Pro Plan'
});
This data is stored with the conversion for reporting. External tracking relies on cookies set when the visitor was on your landing page:
  • blox_vid: Visitor ID (persists for 1 year)
  • blox_sid: Session ID
  • blox_var: The variant they saw
  • blox_exp: The experiment they’re part of (if any)
For cookies to work across domains:
  • Both domains should share a common parent domain (e.g., landing.example.com and shop.example.com)
  • Use a custom domain on Blox that shares this parent domain
  • Cookies are scoped to the registrable domain for cross-subdomain sharing
If your landing page is on landing.example.com and conversions happen on www.example.com, cookies will be readable because both share .example.com.

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Deduplication

External conversions are deduplicated per visitor per goal:
  • First conversion is recorded
  • Subsequent conversions from the same visitor are ignored
  • A 24-hour client-side cookie prevents duplicate beacon sends
This ensures each visitor is counted only once per goal.

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Verifying your setup

To test external tracking:
  1. Visit your landing page (creates the cookies)
  2. Navigate to your conversion page
  3. Check that the tracking script fires (browser dev tools, Network tab)
  4. Verify the conversion appears in Blox
You may need to wait a moment for the conversion to process.

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Using in experiments

External goals work in experiments just like behavioral goals:
  1. Create your experiment
  2. Add the external goal as primary or secondary
  3. Start the experiment
Conversions are attributed to whichever variant the visitor saw, letting you measure which variant drives more purchases, signups, or other downstream actions.

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Troubleshooting

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Conversions not tracking

  • Verify the tracking script is on your conversion page
  • Check that Blox cookies exist (visitor must have visited the landing page first)
  • Ensure the event name matches your goal configuration
  • Look for JavaScript errors in the browser console
  • Confirm your custom domain shares a parent domain with your conversion page
  • Check that cookies aren’t being blocked by browser settings or extensions
  • Verify your site isn’t explicitly clearing or blocking third-party cookies

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Attribution mismatch

  • Conversions are attributed to the variant seen at cookie-creation time
  • If a visitor sees multiple variants (cleared cookies, different devices), only the most recent visit’s variant is tracked
  • Cross-device tracking is not supported

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Privacy considerations

External tracking uses first-party cookies scoped to your domain. However:
  • Inform visitors about tracking in your privacy policy
  • Consider cookie consent requirements for your region
  • The tracking script doesn’t collect personal information beyond what you explicitly pass

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Data sanitization

Blox sanitizes data passed in external conversions:
  • Payloads over 10KB are rejected
  • Strings longer than 500 characters are truncated
  • Common PII field names (password, ssn, credit_card) are filtered out
Avoid passing sensitive personal information in conversion data.