Cross-Domain Tracking: The Decisions That Matter
Configuring analytics so a visit that moves between your own domains, such as from a website to a separate checkout or booking domain, is tracked as one session.
Samir Haddad
What is at stake
Without it, the second domain records the first as a referral, breaking attribution and inflating user counts.
The playbook
- List every domain in the user journey
- Test journeys across domains with debug tools
- Exclude payment providers as referrals
- Check that the linker parameter survives redirects
- Monitor self-referrals in reports
Where it goes wrong
Avoid:
- Your own domains appearing as referral sources
- Redirects that strip the linker parameter
- Separate properties for each domain in one journey
- Ignoring subdomains in the setup
The numbers behind it
| Measure | Figure |
|---|---|
| GA4 setup | domains are listed in the data stream's tag settings |
| Mechanism | a linker parameter is added to links between domains |
| Referral exclusions | unwanted referrals, such as payment providers, can be excluded |
| Third-party checkouts | must support the linker parameter or measurement |
Getting outside help
When to hand it over: Bring in help when checkout or booking runs on another domain, or when self-referrals appear in reports.
Where this comes from
- Google Analytics Help — Set up cross-domain measurement
- Google Analytics Help — Identify unwanted referrals
The figures and practices above come from the sources listed.
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