purchase Event

The purchase event is the final step in the ecommerce funnel. It records successful transactions, including order details, customer information, and itemized product data. This event is vital for conversion tracking, revenue reporting, and campaign attribution.

The purchase model

This model captures complete purchase data for analytics and advertising platforms.

Properties

Name
event
Type
string
Description
Must be set to purchase.
Name
transaction_id
Type
string
Description
Unique identifier for the purchase/order.
Name
user_id
Type
string
Description
ID of the user who completed the purchase.
Name
session_id
Type
string
Description
Session ID for attribution.
Name
ecommerce.currency
Type
string
Description
Currency of the transaction (ISO 4217).
Name
ecommerce.value
Type
float
Description
Total transaction value (including tax and shipping).
Name
ecommerce.tax
Type
float
Description
Tax amount included in the transaction.
Name
ecommerce.shipping
Type
float
Description
Shipping amount charged.
Name
ecommerce.coupon
Type
string
Description
Optional — applied coupon code.
Name
ecommerce.items
Type
array
Description
Array of purchased item objects.
Name
ecommerce.items[].item_id
Type
string
Description
Product or SKU ID.
Name
ecommerce.items[].item_name
Type
string
Description
Product name.
Name
ecommerce.items[].item_brand
Type
string
Description
Brand name.
Name
ecommerce.items[].item_category
Type
string
Description
Product category.
Name
ecommerce.items[].item_variant
Type
string
Description
Variant (e.g., size, color).
Name
ecommerce.items[].price
Type
float
Description
Price per unit.
Name
ecommerce.items[].quantity
Type
int
Description
Quantity purchased.

Push event to the dataLayer

dataLayer.push example

dataLayer.push({
  event: 'purchase',
  transaction_id: 'ORDER-20250401-XYZ',
  user_id: 'user-2024',
  session_id: 'session-abc999',
  ecommerce: {
    currency: 'USD',
    value: 158.97,
    tax: 10.50,
    shipping: 5.00,
    coupon: 'SPRING20',
    items: [
      {
        item_id: 'SKU-555',
        item_name: 'Bluetooth Speaker',
        item_brand: 'SoundBlast',
        item_category: 'Audio',
        item_variant: 'Black',
        price: 79.99,
        quantity: 2
      }
    ]
  }
});

Best Practices

Always include a unique transaction_id.
Use consistent item structure from add_to_cart and view_item.
Track coupon usage to measure promotions and ROI.

Use Cases

The purchase event supports:

Conversion tracking and revenue analysis
Ad platform optimization (GA4, Meta, TikTok)
Attribution modeling and ROAS reporting
LTV and cohort performance analysis