Google Site Tag Setup

Google site tag setup (the former gtag.js) is the foundation of Google's measurement ecosystem on your website. Before the advent of the unified Google Tag, gtag.js was the standard snippet that initialised both GA4 and Google Ads tracking — and millions of websites still have it installed, often in multiple conflicting versions accumulated over years of agency changes and marketing platform additions. Getting Google site tag setup correct means having a single, correctly formatted snippet loading on every page, initialised with the right measurement IDs, and not conflicting with any GTM-deployed tags. This sounds simple but in practice requires careful auditing of existing implementations before any new setup work begins.

Our Google site tag setup service starts with a current-state audit — we check every page template for existing gtag.js snippets, identify duplicate or conflicting initialisation calls, and document which measurement IDs are currently active and which are legacy or incorrect. From that baseline, we configure the correct site tag setup — either migrating to GTM-based Google Tag (our recommendation), or correctly installing a clean gtag.js snippet if GTM is not in use. Where GTM is already present, we ensure the site tag and GTM are not both initialising the same GA4 measurement ID, which is the most common cause of inflated session counts on sites that have had multiple tracking implementations. Post-setup, we verify data collection in GA4 DebugView, confirm Google Ads conversion tag firing, and document the final configuration.