Overview
By default, Upcart takes over Shopify’s cart functionality, which can prevent third-party apps like Klaviyo from detecting cart updates. Fortunately, there are two reliable ways to restore Add to Cart (ATC) tracking in Klaviyo while keeping Upcart active.
Before you begin, make sure Klaviyo Onsite Tracking is properly configured. You can follow their setup guide here:
👉 Klaviyo Onsite Tracking Setup Guide
Option 1: Use AJAX Compatibility (Fastest Setup)
Upcart includes a setting that restores compatibility with other apps by exposing Shopify’s native cart update behavior. When this is enabled, Klaviyo can once again listen for Add to Cart events.
How to enable:
Go to Upcart > Cart Editor > Settings
Enable the setting: Enhanced AJAX API Compatibility
Click Save and test the result
⚠️ Heads up
Enabling this setting gives more control back to other apps, including redirect behaviors. If you see the cart redirecting to Shopify’s default cart page instead of opening the Upcart drawer, we recommend switching to Option 2.
Option 2 (Recommended): Add a Custom Klaviyo Script
This method gives you the best of both worlds, Upcart stays in full control, and Klaviyo tracking still works.
Steps:
Open Upcart > Cart Editor > Settings
Scroll down to the Custom HTML section
From the dropdown, choose Scripts (Before Load)
Paste the following script:
<script>
function TrackATC(){
var _learnq = window._learnq || [];
fetch(`${window.location.origin}/cart.js`)
.then((res) =>
res.clone().json().then((data) => {
var cart = {
total_price: data.total_price / 100,
$value: data.total_price / 100,
total_discount: data.total_discount,
original_total_price: data.original_total_price / 100,
items: data.items,
};
_learnq.push(['track', 'Added to Cart', cart]);
console.log("Klaviyo ATC");
}).catch((e) => {
console.error('Klaviyo add to cart tracking failed', e);
})
);
}
window.upcartOnAddToCart = () => { TrackATC(); };
window.upcartOnAddUpsell = () => { TrackATC(); };
</script>
What this does:
Sends an “Added to Cart” event to Klaviyo any time a product or upsell is added using Upcart
Adds a confirmation message (
Klaviyo ATC) to your browser console so you know it’s working
How to Test Your Setup
To confirm your Klaviyo integration is working properly:
Use your browser’s Console tab to verify the “Klaviyo ATC” log appears after adding a product
Check Klaviyo’s analytics dashboard for ATC event data
If you still don’t see tracking data, confirm that Klaviyo’s onsite scripts are installed and enabled. For help, contact Klaviyo Help Center.
Summary
Method | Benefits | When to Use |
Option 1 – Enable AJAX Compatibility | Fastest setup, no code required | When other apps don’t interfere |
Option 2 – Add Custom Script | Most reliable, Upcart remains in control | When Option 1 causes cart redirect |
If you’re using Klaviyo and Upcart together, this guide should help you track events smoothly while keeping your cart drawer experience intact.
Need more help? Reach out to us via in-app support.