Cross-Site Tracking

Set Up Cross Site Tracking

This guide covers how to set up cross-site tracking between your Shopify store and your resale marketplace. The tracking system enables identity stitching, conversion attribution, and customer journey analytics.

Overview

The Continue tracking system works by:

Dropping a first-party cookie on your main Shopify store via the ct.js script.

Reading that cookie on the marketplace to stitch customer identities across domains.

Firing tracking events at key touchpoints (page views, add-to-cart, checkout) via Google Tag Manager (GTM) and Shopify Custom Pixels.

This enables:

Attribution of marketplace conversions back to the original store session.

Customer journey mapping across store → marketplace → purchase.

Cohort analysis and LTV reporting in the Continue dashboard.

Google Tag Manager (GTM) Setup

1. Install GTM on your Shopify store

⏭️

Already have GTM installed? Skip to step 2.

If you haven't already, add Google Tag Manager to your Shopify theme:

Go to Online Store > Themes > Edit Code.

In theme.liquid, add the GTM container snippet in the <head> section:

html

<!-- Google Tag Manager -->
<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','GTM-XXXXXXX');</script>
<!-- End Google Tag Manager -->

Add the <noscript> fallback immediately after the opening <body> tag:

html

<!-- Google Tag Manager (noscript) -->
<noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-XXXXXXX"
height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
<!-- End Google Tag Manager (noscript) -->

Replace GTM-XXXXXXX with your actual GTM container ID.

2. Create the Continue tracking tag

In your GTM workspace:

Go to Tags > New.

Name it Continue Cross-Site Tracking - Page View

Choose Custom HTML tag type.

Paste the ct.js loader script (see ct.js Script Reference below).

replace YOUR_ORG_ID with your organisation id - please ask someone at Continue for this value

typescript

  <script>
    (function() {
      var s = document.createElement('script');
      s.src = 'https://api.continue.co/engagement/static/ct.js?orgId=YOUR_ORG_ID&endpoint=https://api.continue.co/engagement/api/external-tracking-event';
      document.head.appendChild(s);
    })();
  </script>

Set the trigger to All Pages.

Save and publish.

Shopify Custom Pixel Setup (Checkout Tracking)

Shopify's checkout is sandboxed — GTM tags don't fire there. Use a Custom Pixel to track checkout events.

1. Create the Custom Pixel

In your Shopify Admin, go to Settings > Customer events.

Click the Custom pixels filter.

Click Add custom pixel.

Name it Continue Checkout Tracking.

Paste the following code (replace YOUR_ORG_ID with your organisation id)

javascript

  analytics.subscribe('checkout_completed', (event) => {
    var aid;
    try { aid = localStorage.getItem('__ct_aid'); } catch(e) {}
    if (!aid) return;

    var checkout = event.data.checkout;
    var payload = JSON.stringify({
      anonymousId: aid,
      organisationId: 'YOUR_ORG_ID',
      trackingEventType: 'ExternalPurchase',
      clientUrl: window.location.href,
      metadata: {
        email: checkout.email,
        orderId: String(checkout.order.id),
        orderTotal: parseFloat(checkout.totalPrice.amount)
      }
    });
    var blob = new Blob([payload], { type: 'text/plain' });
    navigator.sendBeacon('https://api.continue.co/engagement/api/external-tracking-event', blob);
  });
  
   analytics.subscribe('product_added_to_cart', (event) => {
    var aid;
    try { aid = localStorage.getItem('__ct_aid'); } catch(e) {}
    if (!aid) return;

    var item = event.data.cartLine;
    var payload = JSON.stringify({
      anonymousId: aid,
      organisationId: 'YOUR_ORG_ID',
      trackingEventType: 'ExternalAddToCart',
      clientUrl: window.location.href,
      metadata: {
        originProductId: String(item.merchandise.product.id),
        variantId: String(item.merchandise.id),
        title: item.merchandise.product.title,
        quantity: item.quantity,
        price: parseFloat(item.merchandise.price.amount)
      }
    });
    var blob = new Blob([payload], { type: 'text/plain' });
    navigator.sendBeacon('https://api.continue.co/engagement/api/external-tracking-event', blob);
  });

Click Save and then Connect the pixel.

Troubleshooting

Make sure you've replaced YOUR_ORG_ID with your actual Continue organisation ID in the ct.js init script

Support

Need help with tracking setup? Contact the Continue team:

Email: hello@continue.co

Adding Excess Stock