Ecommerce Tracking Guide

Quick answer: Good ecommerce tracking sends the full funnel, from view_item to purchase, with item, value and currency data on every event and a unique transaction ID on every order. Build it on a clean dataLayer, send the same events to GA4, Google Ads and Meta, and compare tracked revenue with your store’s real revenue every month.

The events that make up the funnel

• view_item_list and view_item: product discovery.
• add_to_cart and view_cart: buying intent.
• begin_checkout, add_shipping_info, add_payment_info: checkout progress.
• purchase: the result, with transaction_id, value, currency, tax, shipping and items.

With these in place, GA4’s funnel and monetisation reports show exactly where shoppers drop off.

Item data is not optional

Every event should carry an items array with the product ID, name, price, quantity and, ideally, brand and category. Without it you can see that people bought, but not what they bought.

Shopify

The storefront can use GTM, but Shopify’s checkout runs in a protected environment. Use Customer Events with a custom pixel to capture checkout and purchase events reliably, then forward them to GA4, Google Ads and Meta.

WooCommerce

Use a dataLayer plugin or a custom implementation that pushes the standard GA4 ecommerce events, then map them in GTM. Watch out for themes and page builders that change the cart and checkout flow.

Avoid double counting

Thank you pages get reloaded and bookmarked. Use the order number as transaction_id in GA4 and Google Ads, and use the same event_id for the Pixel and CAPI, so each order is counted once.

Reconcile revenue every month

Compare tracked revenue with your store’s sales report. A small gap is normal because of refunds, consent choices and blocked scripts. A large gap usually points to a broken event or a missing checkout step.

FAQ

Want the full funnel tracked correctly? See my ecommerce tracking service.