Event Tracking

What events are tracked

Events capture the actions that matter for business decisions. A pageview tells you someone arrived. Events tell you what they did:

— Engagement events — scroll depth (25%, 50%, 75%, 100%), time on page, video start/complete, file downloads
— Conversion events — form submissions, purchases, add-to-cart, sign-ups, booking confirmations
— Navigation events — outbound clicks, internal link clicks, site search queries
— Custom events — any interaction specific to your product (filter applied, configurator used, calculator completed)

GA4 automatically collects a set of enhanced measurement events (page_view, scroll, click, file_download, video_start, video_complete) without additional configuration. Custom events require either gtag.js calls or GTM triggers. SealMetrics captures 60+ standard events automatically through server-side tracking, including interactions that client-side scripts miss.

GA4 event model

GA4 replaced Universal Analytics’ session-based, hit-type model (pageview, event, social, transaction) with a unified event model. Every data point is an event with parameters. A purchase is an event. A pageview is an event. A session start is an event.

This provides flexibility but introduces complexity. GA4 supports up to 500 distinct event names per property and 25 custom parameters per event. Events are categorized into 4 tiers:

— Automatically collected — first_visit, session_start, user_engagement (no setup needed)
— Enhanced measurement — scroll, click, file_download, video_start (toggle on/off)
— Recommended — Google-defined names like purchase, add_to_cart, sign_up (manual setup)
— Custom — anything else you define (manual setup with custom parameters)

The challenge: all of this depends on the client-side JavaScript executing successfully. If the GA4 script is blocked by an ad blocker — affecting 40%+ of EU visitors — no events are captured at all. Zero pageviews, zero conversions, zero engagement data.

Server-side vs client-side event tracking

Client-side event tracking relies on JavaScript running in the visitor’s browser. This creates three failure points: ad blockers prevent the script from loading, consent banners prevent it from firing, and browser restrictions limit cookie duration.

Server-side event tracking moves data collection to the server layer. Events are captured as HTTP requests process through your infrastructure, before the response reaches the browser. There is no client-side script to block, no cookie to restrict, and no consent dependency for privacy-compliant analytics.

First-party, cookieless event tracking captures interactions across 100% of sessions — providing the complete behavioral dataset that metrics like bounce rate, engagement rate, and conversion rate depend on.