How ecommerce tracking works
Ordinary analytics counts pages and visits. Ecommerce tracking counts products and money. It works by sending a named event at each step a shopper takes — a product list appears, a product page opens, an item goes into the basket, checkout begins, an order completes — and attaching to each event the items involved, with their identifiers, quantities, prices and currency.
Those events reach GA4 either from code built into the shop, from a tag fired by Google Tag Manager reading a data layer, or from your own server once the order is confirmed. That last route matters, because browser-side tracking is the part that ad blockers, privacy settings and unreliable mobile connections interrupt.
Why ecommerce tracking matters
Without it, an online shop is measured like a brochure site: traffic, time on page, perhaps a form. With it, you can see which products people look at but never add, where the basket empties, which channels bring buyers rather than browsers, and what an order is genuinely worth by source.
It is also the only honest way to feed advertising platforms. Bidding towards revenue, building audiences of people who viewed a product, and running dynamic remarketing all draw on the same event stream. Weak ecommerce data does not simply produce weak reports; it produces expensive advertising decisions that look justified at the time.
Where ecommerce tracking goes wrong
The recurring fault is inconsistent item identifiers. If the ID sent with a product view is not the ID sent with the purchase, and neither matches the one in your product feed, nothing joins up and every product-level report is quietly wrong while looking perfectly reasonable.
Currency is the next. A shop selling in rupees but sending events with no currency set, or with a default left as something else, reports revenue that is plausible and false. Duplicated purchase events are the third: a confirmation page a customer can refresh, or a browser event and a server event firing without a shared event ID, inflates orders and quietly ruins every return-on-spend figure built on them.
How to act on it
Plan the events before anyone writes a tag. List the steps in your funnel, name each event using Google’s recommended names rather than your own, and decide exactly which item fields you will send every single time. Then test each step with real products, refresh the confirmation page deliberately to see whether the order counts twice, and reconcile a day of tracked orders against your shop’s own admin before trusting anything.
Make that reconciliation a habit rather than a launch task, because plugins, themes and payment gateways all change under you. If you sell on WooCommerce or Shopify, keep a written note of which plugin or app produces the events, so the next person to touch the site knows what will break. A tracking audit is a sensible starting point on a shop you have inherited with no documentation, and your ecommerce SEO decisions depend on the same product data being correct.