In 2024, Shopify migrated stores from the old checkout.liquid system to the new Checkout Extensibility framework. This change broke purchase event tracking for thousands of Shopify stores — often silently, without any error messages. If your GA4 purchase numbers dropped or your Meta Pixel stopped recording purchases, Shopify’s checkout extensibility update is the most likely cause.
What Is Shopify Checkout Extensibility?
Checkout Extensibility is Shopify’s newer system for customising the checkout experience. It replaced checkout.liquid (the old method) with a system built on Shopify’s own UI extensions, checkout apps, and Customer Events API.
The key change for tracking: in the old system, you could inject scripts directly into the checkout pages, including the thank you page. In the new system, direct script injection to the checkout is blocked. Instead, all tracking on checkout pages must go through Shopify’s Customer Events system.
How It Broke Tracking
Before checkout extensibility, most Shopify tracking implementations worked by:
- Adding tracking scripts directly to the checkout pages via Settings → Checkout → Additional Scripts
- Or using a theme app that injected scripts into checkout.liquid
After checkout extensibility, these scripts still run on the storefront (all pages before checkout) but they no longer have access to the thank you page in the same way. The purchase event — which fires on the thank you page — stopped working for many stores that used the old script injection method.
The result: GA4 recorded sessions, product views, and add-to-cart events correctly, but purchase events dropped significantly or stopped entirely. Meta Pixel and TikTok Pixel had the same problem. Conversion tracking in Google Ads and Meta Ads dropped, affecting smart bidding performance.
The Correct Fix: Use Customer Events
Shopify’s Customer Events system is the approved replacement for script injection on checkout pages. Instead of injecting JavaScript directly, you create a Customer Event Pixel in Shopify that subscribes to Shopify’s built-in events (checkout_completed, product_added_to_cart, etc.) and fires your tracking code when those events occur.
How to Set Up Customer Events for GA4
- Go to Shopify Admin → Settings → Customer Events
- Click Add pixel and select Custom pixel
- Name it (e.g. “GA4 Purchase Tracking”)
- Write the pixel code that subscribes to checkout_completed and fires the GA4 purchase event with the order data
- Save and connect it to your live store
How to Set Up Customer Events for Meta Pixel
Meta’s official Shopify app (Meta — Facebook & Instagram) was updated in 2024 to use Customer Events automatically. If your Meta app is up to date, it should already be using this system. Check your Meta app version in Shopify and update to the latest version if it is not current.
How to Set Up Customer Events for TikTok Pixel
Similarly, TikTok’s official Shopify app was updated to use Customer Events. Update the TikTok app in Shopify and verify in TikTok Events Manager that CompletePayment events are still arriving. If they stopped after a Shopify update, reinstalling the TikTok app often resolves it.
How to Tell If Checkout Extensibility Broke Your Tracking
Compare these two numbers in GA4 for the last 30 days:
- GA4 purchase event count
- Shopify total orders
If GA4 is missing more than 15% of your Shopify orders, you likely have a checkout extensibility tracking issue. Also check the date when the gap started — if it correlates with a Shopify update notification you received, that confirms it.
Additional Scripts: Does It Still Work?
Settings → Checkout → Additional Scripts still exists on some Shopify plans, but its behaviour changed. Scripts added there may not have access to the purchase confirmation data in the same way. For reliable purchase tracking, Customer Events is the correct approach going forward.
Is This Already Fixed If I Use a Third-Party App?
Only if the app has been updated to use Customer Events. Many older tracking apps and GTM-based setups have not been updated and are still using the old script injection method. The app appearing to work in the dashboard does not mean it is tracking checkout purchases correctly.
The only way to confirm is to compare your app-reported conversions to your actual Shopify order count for the same period.
Get Your Checkout Tracking Fixed
Shopify’s checkout extensibility change is the most common reason Shopify store owners see their conversion tracking data drop in 2024–2025. If you have not audited your tracking since the Shopify checkout update, there is a good chance you are missing a significant portion of your purchase events.
We diagnose exactly which tracking implementations broke and fix them with the correct Customer Events setup. Book your free Shopify tracking audit here.