E-commerce Event Schema: The Complete Reference

Reading time: 10 min · Last updated: January 2026

A complete reference for GA4 e-commerce tracking. All events, parameters, and implementation examples in one place — copy-paste ready for your data layer.

E-commerce Funnel Overview
Product Discovery Events
Cart Events
Checkout Events
Purchase & Refund
Promotion Events
Items Array Reference
Validation Checklist

E-commerce Funnel Overview

GA4 tracks the complete shopping journey through these events:

“The most important events are view_item, add_to_cart, begin_checkout, and purchase — these populate GA4’s default Ecommerce purchases report.”
— Google Analytics Documentation

Product Discovery Events

view_item_list

Fire when a user sees a list of products (category page, search results, recommendations).

Parameter	Type	Required	Example
`item_list_id`	string	No	“category_shoes”
`item_list_name`	string	No	“Running Shoes”
`items`	array	Yes	[{item_id, item_name, …}]

select_item

Fire when a user clicks on a product from a list.

Parameter	Type	Required	Example
`item_list_id`	string	No	“search_results”
`item_list_name`	string	No	“Search Results”
`items`	array	Yes	[{item_id, item_name, index}]

view_item

Fire when a user views a product detail page.

Parameter	Type	Required	Example
`currency`	string	Yes	“EUR”
`value`	number	Yes	99.99
`items`	array	Yes	[{item_id, item_name, price}]

Cart Events

add_to_cart

Fire when a user adds a product to the shopping cart.

Parameter	Type	Required	Example
`currency`	string	Yes	“EUR”
`value`	number	Yes	99.99
`items`	array	Yes	[{item_id, item_name, price, quantity}]

Data Layer Example:

dataLayer.push({
  event: "add_to_cart",
  ecommerce: {
    currency: "EUR",
    value: 99.99,
    items: [{
      item_id: "SKU_12345",
      item_name: "Running Shoes Pro",
      price: 99.99,
      quantity: 1,
      item_brand: "SportBrand",
      item_category: "Shoes",
      item_category2: "Running"
    }]
  }
});

view_cart

Fire when a user views their shopping cart.

remove_from_cart

Fire when a user removes a product from the cart.

Both events use the same parameters as add_to_cart.

Checkout Events

begin_checkout

Fire when a user starts the checkout process.

Parameter	Type	Required	Example
`currency`	string	Yes	“EUR”
`value`	number	Yes	199.98
`coupon`	string	No	“SUMMER20”
`items`	array	Yes	[…]

add_shipping_info

Fire when a user submits shipping information.

Parameter	Type	Required	Example
`shipping_tier`	string	No	“Express”
+ currency, value, coupon, items

add_payment_info

Fire when a user submits payment information.

Parameter	Type	Required	Example
`payment_type`	string	No	“Credit Card”
+ currency, value, coupon, items

Purchase & Refund

purchase

Fire when a transaction is completed. This is the most important e-commerce event.

Parameter	Type	Required	Example
`transaction_id`	string	Yes	“ORD-2026-001234”
`currency`	string	Yes	“EUR”
`value`	number	Yes	189.98
`tax`	number	No	36.10
`shipping`	number	No	5.99
`coupon`	string	No	“SUMMER20”
`items`	array	Yes	[…]

Important: Each transaction_id must be unique. Duplicate IDs will be deduplicated in GA4 reports.

Data Layer Example:

dataLayer.push({
  event: "purchase",
  ecommerce: {
    transaction_id: "ORD-2026-001234",
    currency: "EUR",
    value: 189.98,
    tax: 36.10,
    shipping: 5.99,
    coupon: "SUMMER20",
    items: [{
      item_id: "SKU_12345",
      item_name: "Running Shoes Pro",
      price: 99.99,
      quantity: 2,
      item_brand: "SportBrand",
      item_category: "Shoes"
    }]
  }
});

refund

Fire when an order is refunded (full or partial).

Uses the same parameters as purchase. For partial refunds, include only the refunded items in the items array.

Promotion Events

view_promotion

Fire when a promotion banner or block is displayed.

select_promotion

Fire when a user clicks on a promotion.

Parameter	Type	Example
`promotion_id`	string	“summer_sale_2026”
`promotion_name`	string	“Summer Sale 20% Off”
`creative_name`	string	“Hero Banner Blue”
`creative_slot`	string	“homepage_hero”

Items Array Reference

Every e-commerce event requires an items array. Here are all available item parameters:

Parameter	Type	Required	Description
`item_id`	string	Yes*	SKU or product ID
`item_name`	string	Yes*	Product name
`price`	number	No	Unit price
`quantity`	number	No	Number of items
`item_brand`	string	No	Brand name
`item_category`	string	No	Primary category
`item_category2-5`	string	No	Sub-categories (up to 5 levels)
`item_variant`	string	No	Size, color, etc.
`index`	number	No	Position in list
`discount`	number	No	Discount amount
`coupon`	string	No	Item-level coupon

* Either item_id or item_name is required. Best practice: include both.

Validation Checklist

Before going live, verify your implementation:

☐	Currency is consistent — same format across all events (EUR, not €)
☐	Values are numbers — not strings (“99.99” vs 99.99)
☐	Transaction IDs are unique — no duplicates across purchases
☐	Items array is present — even for single-product events
☐	item_id or item_name exists — at least one is required
☐	Events fire in correct order — view_item before add_to_cart before purchase
☐	No PII in parameters — no emails, names, or addresses
☐	Test in GA4 DebugView — verify events appear correctly

Further Reading:

Written by

Lukas Meier

Product Analytics Specialist with 10 years of experience configuring tracking for e-commerce and SaaS products across Europe. Creator of EU-Medin.