Lesson 8 of 8
Practice: The Checkout_completed Event
Time to build it. The hands-on lesson Shopify checkout_completed simulates exactly what a Shopify custom pixel pushes — the same checkout_completed object, with orderId, currency, value, shipping, tax and an items array — straight into the dataLayer, so you can practise the GTM side without a live store.
Your job in the practice lesson
- Click the button to fire a simulated
checkout_completedpush. - Add a Data Layer Variable for each field you want to send.
- Add a Custom Event trigger named exactly
checkout_completed. - Build a GA4 purchase tag mapping
transaction_id,value,currency,shipping,taxanditems. - Confirm in Preview that it fires once with the right values.
The only difference from production is the environment: here GTM Preview does connect, because the push happens on a normal page rather than inside Shopify's checkout sandbox. Everything you build — the variables, the trigger name, the purchase tag — is identical to the real thing.
Key takeaway
Practise the GTM half against a simulated Shopify push: same fields, same trigger name, same purchase tag. On a real store only the testing environment changes — the build does not.