Demystifying Cross-Domain Tracking in Google Analytics 4

25th Apr 2024

4 Minutes Read

By Anshul Dhurandhar

Within the continuously growing digital realm, it's common for businesses to operate across several domains, leveraging a range of platforms and websites to connect with users through multiple touchpoints. Google Analytics 4 (GA4), the newest version of Google's analytics service, brings advanced cross-domain tracking features designed to provide businesses with a detailed view of user activities across various domains. This detailed guide will explore the complexities of cross-domain tracking within GA4, discussing its importance, how to implement it, and the best practices to follow.

I. The Significance of Cross-Domain Tracking:

Cross-domain tracking is essential for businesses that operate multiple websites or have various digital properties. Without cross-domain tracking, user interactions on different domains are treated as separate sessions, leading to fragmented data and an incomplete view of user behavior. GA4's cross-domain tracking bridges this gap, allowing businesses to connect user sessions across domains and create a holistic view of the user journey.

II. Implementation Steps for Cross-Domain Tracking in GA4:

  • Set Up a GA4 Property:
  • If you haven't already, create a GA4 property for each domain you want to track. Follow the setup process provided by Google Analytics.

  • Configure Cross-Domain Settings:
  • In the GA4 property, navigate to the "Admin" section.
  • Under the "Property," select "Data Streams."

  • Click on the data stream for the domain you want to configure for cross-domain tracking.
  • In the "Configurations" tab, find the "Configure your Domains" section.

  • Enter Domains to Link:
  • Enter the domains that you want to link to the current property. These could include your main domain, subdomains, or entirely different domains that are part of your digital ecosystem.

  • Update Tracking Code:
  • Ensure that the GA4 tracking code is installed on all pages of the domains you're linking.
  • The tracking code should include the "gtag('config', 'GA_MEASUREMENT_ID');" snippet with the GA Measurement ID specific to your property.

III.  Working Principle of Cross Domain Tracking:

If you have any links redirecting to your other domains configured in the GA4 setting, the script will automatically append _gl parameter to those links.

On clicking on this link, you will be redirected to the other domain and GA4 script will capture this query parameters and will generate the same Client ID and Session ID on the new domain. This will ensure the session unification over cross domain.

IV.  How to test Cross Domain Tracking:

To confirm your cross-domain configuration, click the link on the initial website that redirects you to the second site. Ensure that the URL of the second website includes the _gl= parameter. Additionally, verify if the _ga cookie remains consistent between both domains. Refer to the provided screenshot for guidance and conduct this verification process on both domains. It is crucial that the value of the ga cookie matches across both domains. Pay close attention to the "Domain" column in the cookie list for accurate confirmation. It is also crucial to have the same session ID (sid) for both the domains.

V. Best Practices for Cross-Domain Tracking in GA4:

A. Include All Relevant Domains:

  • Ensure that all domains within your digital ecosystem are included in the cross-domain tracking configuration. This encompasses main domains, subdomains, and any external domains that contribute to the user journey.

B. Consistent Measurement IDs:

  • Maintain consistency in the GA Measurement IDs used across domains. This ensures accurate data aggregation and avoids discrepancies in tracking.

C. Referral Exclusion List:

  • Review and update the referral exclusion list to prevent self-referrals and maintain accurate source/medium attribution across domains.

D. User Privacy Considerations:

  • Adhere to privacy regulations and user consent requirements. Clearly communicate your data collection practices and provide users with options to manage their preferences.

E. Regular Audits and Testing:

  • Conduct regular audits of cross-domain tracking configurations to identify and rectify any discrepancies.
  • Continuously test the implementation to ensure seamless user tracking across domains, especially after website updates or changes.

VI. Troubleshooting Cross-Domain Tracking Issues:

  • Check Configuration Settings:
  • Verify that the cross-domain tracking settings are correctly configured in the GA4 property.

  • Review Tracking Code Implementation:
  • Ensure that the GA4 tracking code is correctly implemented on all pages of the linked domains.

  • Debugging Tools:
  • Utilize browser developer tools and GA DebugView to identify any errors or issues in the tracking implementation.

  • Check for Redirects:
  • Redirects between domains can sometimes disrupt tracking. Ensure that redirects are configured appropriately.

  • Session Unification:
  • If users are still experiencing fragmented sessions, review and adjust session settings to unify sessions across domains.

VII. Conclusion:

Cross-domain tracking in Google Analytics 4 is a powerful feature that empowers businesses to gain a comprehensive understanding of user interactions across their digital ecosystem. By seamlessly connecting user sessions across domains, GA4 facilitates more accurate insights into the user journey, contributing to informed decision-making and enhanced user experiences. Through meticulous implementation, adherence to best practices, and ongoing monitoring, businesses can harness the full potential of cross-domain tracking in GA4, ensuring a unified and insightful analytics ecosystem.