Google Analytics 4 — the event-based analytics platform that replaced Universal Analytics in 2023. The standard for ecommerce behavior measurement.
GA4 in plain English
GA4 is fundamentally different from its predecessor Universal Analytics (UA). UA was session-based and pageview-centric. GA4 is event-based — every interaction (page view, scroll, click, video play, file download, purchase, custom action) is recorded as an event with custom parameters. This model is more flexible but requires learning the new vocabulary and the new reporting paradigm.
For ecommerce, GA4's value is its native ecommerce events: view_item (product detail viewed), add_to_cart, begin_checkout, purchase (with revenue and items), and refund. Configured correctly, GA4 shows you funnel completion rates, product-level revenue attribution, and per-channel conversion rates. The Shopify-GA4 integration handles most of this automatically; for custom storefronts, you implement the events explicitly.
GA4's headline strength is BigQuery export — every event your property records can be streamed to BigQuery (Google's data warehouse) for SQL analysis. UA had this only on the paid 360 tier; GA4 makes it free. For analytical depth beyond GA4's UI, this is the door. Many ecommerce teams use GA4 for day-to-day monitoring and BigQuery for cohort analysis, LTV modeling, and attribution.
Gotchas: data thresholds (GA4 hides metrics when sample size is small to protect user privacy, which can be confusing — "why does this report show zero?"), default attribution model changed from last-click to data-driven (different attribution to channels than UA showed), real-time reports are useful but the standard reports have a 24-48 hour processing delay for full accuracy, and the UI is genuinely worse than UA's for ad-hoc exploration. Allow time for the learning curve.
Why ga4 matters for ecommerce
GA4 is now table stakes — every ecommerce platform integrates with it, every digital marketing channel reports against it, every agency uses it as the source of truth. For 6-to-8-figure stores, GA4 is the substrate for understanding what's driving revenue and what's leaking it. The funnel reports show where shoppers drop out; the audience exploration shows which segments convert; the attribution comparison shows which marketing dollars are working. Set up correctly, GA4 makes every other tool more useful by being the canonical behavior data source.