Crazy Egg Cross-Domain Tracking

How Crazy Egg Identifies Visitors

Crazy Egg uses a first-party cookie (_ceir, is_returning) scoped to the domain where the tracking script loads. Unlike GA4 or Meta Pixel, Crazy Egg does not stitch user sessions across domains. Each domain is tracked independently, and there is no built-in cross-domain linking mechanism.

This means Crazy Egg is fundamentally a per-page analysis tool, not a cross-domain journey tracker. Heatmaps, scrollmaps, and recordings are always scoped to a single URL.

Subdomain Tracking

Crazy Egg automatically tracks across subdomains when the same account script is installed on all subdomains. The tracking cookie is set on the root domain (.example.com), so it persists across:

• www.example.com
• shop.example.com
• blog.example.com
• app.example.com

No additional configuration is needed. Install the same script on each subdomain:

<!-- Same Crazy Egg script on all subdomains -->
<script type="text/javascript" src="//script.crazyegg.com/pages/scripts/0000/0000.js" async></script>

Create separate snapshots for each subdomain URL you want to analyze. Crazy Egg will not automatically snapshot all subdomains -- you must specify each URL explicitly.

Multi-Domain Setup

For completely separate domains (e.g., example.com and example-checkout.com), Crazy Egg treats each as an independent site. There is no session stitching.

Single Account, Multiple Domains

You can track multiple domains under one Crazy Egg account:

1. Install the tracking script on every domain (the script is the same regardless of domain)
2. Create snapshots for each domain's pages individually
3. View data per-domain in the Crazy Egg dashboard

// Verify Crazy Egg is loaded on any domain by checking the console
if (typeof CE2 !== 'undefined') {
  console.log('Crazy Egg loaded. Account:', CE2.pid);
} else {
  console.log('Crazy Egg not detected on this page');
}

Snapshot Configuration for Multiple Domains

When creating snapshots across domains, use exact URLs or wildcard patterns:

Each snapshot consumes one from your plan's snapshot quota. Plans range from 100 to unlimited snapshots depending on tier.

Linking User Identity Across Domains

While Crazy Egg has no native cross-domain ID, you can use the User ID feature to tag visitors with a known identifier that persists across domains:

// On Domain A: set user ID when known (e.g., after login)
CE2.set(5, 'user-12345');  // Custom variable slot 5

// On Domain B: set the same user ID
// Pass the ID via URL parameter, server session, or auth token
var userId = new URLSearchParams(window.location.search).get('uid');
if (userId) {
  CE2.set(5, userId);
}

This does not merge sessions in Crazy Egg's UI, but it allows you to filter recordings by user ID and manually correlate behavior across domains.

Recordings Across Domains

Crazy Egg recordings capture individual page sessions. When a user navigates from Domain A to Domain B:

• The recording on Domain A ends when the user leaves
• A new, separate recording starts on Domain B
• There is no visual connection between the two recordings

To analyze cross-domain flows, filter recordings on both domains by the same time window and user ID (if set), then review them sequentially.

Snapshot Plan Limits by Tier

All plans support unlimited domains. The constraint is snapshot count, not domain count.

When to Use a Different Tool

Crazy Egg is best for per-page UX analysis (heatmaps, scrollmaps, click tracking). If your primary need is cross-domain journey tracking, session replay across domains, or funnel analysis spanning multiple sites, consider pairing Crazy Egg with:

• Google Analytics 4 for cross-domain session stitching and funnel reporting
• FullStory or Hotjar for cross-domain session replay with identity linking
• Mixpanel or Amplitude for event-based cross-domain user journeys

Use Crazy Egg for what it does best -- visual page-level analysis -- and supplement with journey-focused tools for cross-domain flows.

Related

• Crazy Egg Setup
• Global Cross-Domain Tracking Guide