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Sometimes the standard event data isn’t enough. You may want to enrich your analytics events with additional context from the checkout session—such as whether the user is a VIP member, their loyalty tier, or platform-specific data. Ollie Shop exposes session context through global objects that you can access directly from GTM.

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Real-World Example: Enriching VIP Enrollment

In the Custom Events guide, we created a vip_enrollment event that fires when a customer joins your VIP program. Now let’s enrich that event with additional context from the checkout session. Using a GTM Custom HTML tag, you can add the customer’s VIP status from your platform’s session data: 
<script>
  var session = window.__CHECKOUT_SESSION__ || {};

  dataLayer.push({
    event: 'vip_enrollment_enriched',
    enrollment_source: 'checkout',
    is_guest: session.user?.isGuest || false,
    cart_value: session.totals?.total || 0
  });
</script>

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Available Session Objects

Ollie Shop exposes two global objects with checkout session data. For a complete reference with full examples, see the Session documentation.
ObjectDescription
window.__CHECKOUT_SESSION__Ollie Shop’s normalized session data
window.__RAW_CHECKOUT_SESSION__Raw platform session (VTEX, Shopify, etc.)

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Common Use Cases

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User Segmentation

Enrich events with user attributes for better segmentation in analytics: 
<script>
  var session = window.__CHECKOUT_SESSION__ || {};

  dataLayer.push({
    event: 'checkout_step_completed',
    user_type: session.user?.isGuest ? 'guest' : 'registered',
    cart_value: session.totals?.total || 0,
    item_count: session.cartItems?.length || 0
  });
</script>

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Platform-Specific Data

Access raw platform data when you need fields not available in the normalized session: 
<script>
  var rawSession = window.__RAW_CHECKOUT_SESSION__ || {};

  dataLayer.push({
    event: 'vtex_checkout_data',
    sales_channel: rawSession.salesChannel,
    trade_policy: rawSession.tradePolicy,
    seller_id: rawSession.sellers?.[0]?.id
  });
</script>

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Setting Up in GTM

1

Create a Custom HTML Tag

In GTM, go to Tags > New > Tag Configuration > Custom HTML. Paste your enrichment script.
2

Set the Trigger

Configure the tag to fire on the appropriate trigger—for the VIP enrollment example, use a Custom Event trigger matching vip_enrollment.
3

Test in Preview Mode

Use GTM Preview mode to verify your enriched events are pushing correctly to the dataLayer.
4

Publish

Once verified, publish your GTM container to apply changes to your live checkout.

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Best Practices

  • Always use fallbacks — Use || {} and || false to prevent errors if session objects aren’t loaded yet
  • Keep scripts lightweight — GTM Custom HTML runs synchronously; complex logic can impact checkout performance
  • Use descriptive event names — Suffix enriched events (e.g., *_enriched) to distinguish them from the original events
  • Test thoroughly — Session data availability may vary depending on checkout stage

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Further Reading