How to migrate from client-side to server-side Google Tag Manager
Migrating from client-side to server-side Google Tag Manager is one of the most common analytics projects on marketing team backlogs right now. Ad blockers, Safari's Intelligent Tracking Prevention and consent regulations keep removing events before they reach GA4 or Google Ads. What server-side GTM actually is Client-side GTM loads a container script in the visitor's browser. That script fires tags. Server-side GTM adds a second container that runs on your own cloud infrastructure and receives events over a subdomain of your website. The browser sends one lean request to your subdomain. The server container reads it, applies any transformation or filtering logic, then forwards clean events to Google Ads, GA4, Meta Conversions API and any other supported endpoint. Why the migration matters Cookies set by your subdomain read as first-party, so Safari keeps them beyond the seven-day limit that hits browser-set cookies. Requests to your own subdomain sit outside typical ad...