Process Flow
Animated overview of the full workflow
TL;DR
Cross-domain tracking lets you track users as they move between two or more domains you own (e.g., your main site and a separate checkout domain) as a single session. Without it, each domain creates a new session, breaking your conversion funnel data. Configure in GA4 Admin > Data Streams > your stream > Configure tag settings > Configure your domains. Add all domains that should share the same user session.
When You Need It
When your conversion flow spans multiple domains — for example, your marketing site is on yourbrand.com but checkout happens on shop.yourbrand.com or a third-party payment page. Without cross-domain tracking, the transition appears as a referral, creating a new session and losing the original traffic source.
Step-by-Step Guide
Follow these 3 steps to complete this guide
- 1
Setup
Admin > Data Streams > select your stream > Configure tag settings > Configure your domains. Add each domain that should share session data. GA4 automatically adds a linker parameter to URLs when users navigate between listed domains.
- 2
Verification
Use DebugView to confirm sessions carry across domains. Navigate from one domain to another and verify the same client_id persists.
- 3
Common Issues
Forgetting to add all domains. Redirects stripping the linker parameter. Third-party domains that cannot accept linker parameters (payment processors, booking engines).
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