Clicky Cross-Domain Tracking

Track users across multiple domains with Clicky analytics for unified visitor journeys.

Cross-Domain Tracking Overview

Cross-domain tracking allows you to follow a visitor's journey across multiple domains or subdomains, treating them as a single session rather than separate visits.

When You Need Cross-Domain Tracking

Common scenarios:

Main site + checkout domain: example.com → checkout.example-pay.com
Multiple brand sites: brand-a.com → brand-b.com
Subdomains: www.example.com → shop.example.com → blog.example.com
Landing pages: campaign.example.com → www.example.com

Subdomain Tracking

Automatic Subdomain Tracking

Clicky automatically tracks across subdomains of the same root domain. A visitor moving from www.example.com to shop.example.com is tracked as one session.

Ensure your tracking code uses the same Site ID on all subdomains:

<!-- Same code on all subdomains -->
<script>
  var clicky_site_ids = clicky_site_ids || [];
  clicky_site_ids.push(YOUR_SITE_ID);
</script>
<script async src="//static.getclicky.com/js"></script>

If automatic tracking isn't working across subdomains:

var clicky_custom = clicky_custom || {};
clicky_custom.cookie_domain = '.example.com';  // Note the leading dot

Cross-Domain Tracking (Different Domains)

Link Decoration Method

Pass the visitor ID via URL parameters when linking between domains:

// On source domain
function decorateLink(url) {
  if (typeof clicky !== 'undefined' && clicky.visitor_id) {
    var separator = url.indexOf('?') !== -1 ? '&' : '?';
    return url + separator + '_clicky_visitor=' + clicky.visitor_id();
  }
  return url;
}

// Apply to cross-domain links
document.querySelectorAll('a[href*="otherdomain.com"]').forEach(function(link) {
  link.addEventListener('click', function(e) {
    this.href = decorateLink(this.href);
  });
});

Reading Decorated Parameters

On the destination domain, Clicky automatically reads the _clicky_visitor parameter and associates the session.

Form Submission

For forms that submit to another domain:

document.getElementById('cross-domain-form').addEventListener('submit', function() {
  if (typeof clicky !== 'undefined' && clicky.visitor_id) {
    var input = document.createElement('input');
    input.type = 'hidden';
    input.name = '_clicky_visitor';
    input.value = clicky.visitor_id();
    this.appendChild(input);
  }
});

Multi-Site Tracking

Single Site ID Approach

Track all domains under one Clicky site:

Pros:

Unified visitor journey
Single dashboard
Cross-domain attribution

Cons:

Can't separate traffic by domain easily
Harder to compare domain performance

Multiple Site IDs Approach

Use different Site IDs for each domain:

Pros:

Separate reports per domain
Cleaner data segmentation

Cons:

Visitors counted separately per domain
No cross-domain journey tracking

Hybrid Approach

Track with both a primary Site ID and domain-specific IDs:

var clicky_site_ids = clicky_site_ids || [];
clicky_site_ids.push(PRIMARY_SITE_ID);      // All domains
clicky_site_ids.push(DOMAIN_SPECIFIC_ID);   // This domain only

Verification

Testing Cross-Domain Tracking

Start on Domain A and note the visitor ID (use browser console)
Click a link to Domain B
On Domain B, verify the visitor ID matches
Check Clicky's real-time view to confirm single session

Debug Visitor ID

// In browser console
if (typeof clicky !== 'undefined') {
  console.log('Visitor ID:', clicky.visitor_id());
}

Troubleshooting

Session Breaking Between Domains

Verify link decoration is working
Check that destination domain reads the parameter
Ensure same Site ID on both domains

Subdomain Issues

Confirm cookie domain is set correctly
Check for conflicting cookie settings
Verify no duplicate tracking codes

Modern browsers restrict third-party cookies. Use:

First-party tracking mode
Link decoration for cross-domain
Server-side tracking where possible