Definition
Server-side tracking (or server-side tagging) involves executing tracking scripts on an intermediary server rather than in the visitor's browser. With GTM Server-Side, a single request is sent from the browser to a server container (hosted on Google Cloud, AWS, or other), which then redistributes data to different platforms (Google Analytics, Facebook, etc.). For SEO, the benefits are significant: 50-80% reduction in third-party JavaScript in the browser (Core Web Vitals improvement), more reliable tracking (resistant to browser ad blockers), better data control (GDPR compliance), and server-side data enrichment. The cost is an additional server ($20-50/month for a standard site) and more complex setup.
Key Points
- 50-80% reduction of tracking JavaScript in the browser
- More reliable tracking, resistant to browser ad blockers
- Better personal data control for GDPR compliance
Practical Examples
Migration to GTM Server-Side
An e-commerce site migrates its 12 tracking tags to GTM Server-Side. TBT (Total Blocking Time) decreases by 60%, tracking becomes resistant to ad-blockers, and GDPR compliance is simplified.
Data enrichment
Via server-side tracking, a site enriches GA4 events with CRM data server-side (customer segment, LTV) without exposing this information in the browser.
Frequently Asked Questions
No. It requires a server to host the container (Google Cloud App Engine recommended, approximately $20-50/month). GTM Server-Side itself is free, but the server infrastructure has a cost.
Partially. By using a first-party subdomain (sst.yoursite.com) for the server container, requests are no longer blocked by classic ad-blocker lists. However, advanced blockers may still detect certain patterns.
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Last updated: 2026-02-07