Tracking post purchase conversions is different from regular user tracking in your store.
Shopify supports two types of pixels:
App pixels - these are automatically installed through marketing or analytics apps.
Custom pixels - These pixels are manually created and managed in the Customer events section of your Shopify admin.
But neither of those works with post-purchase conversions.
In order to capture Post Purchase conversions, you need to listen to the CheckoutAmended event. It is a special Shopify Checkout Extension event that fires when an order is updated after checkout, such as when a post-purchase upsell is accepted.
CheckoutAmended is not supported in the Customer Events (pixels manager)
In order to utilize upsell Purchase events, you must use the Post-purchase page Additional scripts field. You can find it in admin Settings -> Checkout -> Post-purchase page:
Important notes for scripts field:
Shopify liquid is not supported
It's allowed to use only <script> HTML tag. Anything else is not supported.
Script runs in hopify sandbox, so there's no possibility to access any data from DOM.
Example - Google Analytics:
<!-- Google tag (gtag.js) -->
<script async src="https://www.googletagmanager.com/gtag/js?id=G-XXXXXXXXXX"></script>
<script>
window.dataLayer = window.dataLayer || [];
function gtag(){dataLayer.push(arguments);}
gtag('js', new Date());
gtag('config', 'G-XXXXXXXXXX');
</script>
<script>
Shopify.on('CheckoutAmended', function(updatedOrder, oldOrder) {
const originalOrder = oldOrder.order || oldOrder;
const originalItems = originalOrder.lineItems.map(function (line) {
return line.id;
});
const addedItems = updatedOrder.lineItems.filter(function (line) {
return oldItems.indexOf(line.id) < 0;
});
var items = [];
var totalValue = 0;
for (var i = 0; i < addedItems.length; i++) {
var newItem = addedItems[i];
items.push({
'id': newItem.product.id,
'quantity': newItem.quantity,
'price': newItem.finalPrice
});
totalValue += newItem.finalPrice;
}
gtag('event', 'purchase', {
'totalPrice': totalValue,
'currency': updatedOrder.currency,
'items': items
});
});
</script>
Don't forget to use your Google-Tag ID instead of G-XXXXXXXXXX