add_to_cart

A user adds items to the cart.

Status: Active

Availability: Live for checkout; CMS cart coming soon.

Triggered when a user adds one or more items to the cart on a booking site or adds extras/upgrades in the checkout portal.

GA4 docs: https://developers.google.com/analytics/devguides/collection/ga4/reference/events?client_type=gtag#add_to_cart

If the add-to-cart action comes from availability search, a search snapshot is included (same shape as search_results_loaded.search).

Sample data layer snippet

dataLayer.push({ ecommerce: null });  // Clear the previous ecommerce object.  dataLayer.push({  "event": "add_to_cart",  "ecommerce": {    "currency": "EUR",    "value": 350.0,    "items": [      {        "item_id": "123123",        "item_name": "4-Person Luxury Villa",        "item_brand": "Administration Name",        "affiliation": "Website",        "checkout_item_id": "987654",        "item_category": "Accommodation",        "item_category2": "house",        "item_variant": "single_night",        "item_list_id": "cart",        "item_list_name": "Cart",        "item_country": "Netherlands",        "item_region": "Twente",        "item_city": "Enschede",        "administration_id": "321321",        "administration_name": "Administration Name",        "park_id": "321321",        "currency": "EUR",        "coupon": "SUMMER10",        "discount": 25.0,        "price": 350.0,        "quantity": 1,        "index": 1,        "start_date": "2026-02-20",        "end_date": "2026-02-22",        "google_business_vertical": "hotel_rental"      }    ]  }});

Top-level objects

Parameter	Sample	Presence	Description
`ecommerce`	`{...} (see below)`	always	Ecommerce payload wrapper for GA4 events.

`ecommerce`

Ecommerce payload wrapper for GA4 events.

Field	Sample	Presence	Description
`currency`	`EUR`	always	Currency of the items associated with the event, in 3-letter ISO 4217 format. Source: Currency used for totals/items (booking/order/reservation currency; availability/property search uses the active site currency).
`value`	`350.0`	always	Total value of the event. Source: Total order/booking value or sum of item prices.
`items[]`	`[...] (see below)`	always	Items array for the ecommerce payload.

`ecommerce.items[]`

Items array for the ecommerce payload.

Field	Sample	Presence	Description
`item_id`	`123123`	always	ID of the item. Combine with item_category and item_category2. Source: rentable type id (Accommodation), cost id (Upgrade, Preference), bundle id (Package), or amenity id (Preference with Amenity item_category2). Availability/property search: category or property id. Notes: Legacy checkout portal used prefixed ids (A/C/P). Legacy CMS add_to_cart only sent the rentable type id.
`item_name`	`4-Person Luxury Villa`	if available	The name of the item. Source: rentable type id (Accommodation), cost id (Upgrade, Preference), bundle id (Package), or amenity id (Preference with Amenity item_category2). Availability/property search: localized category/property name.
`item_brand`	`Administration Name`	if available	The localized name of the site. Source: Checkout portal: administration name. Availability/property search: site/brand name shown on the website (can differ from the administration name).
`affiliation`	`Website`	if available	Deprecated
`checkout_item_id`	`987654`	if available	Deprecated - use `item_id` with `item_category` to identify items
`item_category`	`Accommodation`	if available	Top-level item type. `Accommodation` `Upgrade` `Preference` `Package` Source: Checkout portal: `Accommodation` for rentable types, `Upgrade` for extras, `Preference` for amenities/preferences, `Package` for bundles. Availability/property search: `Accommodation`.
`item_category2`	`house`	if available	Semantic segment for accommodations or sub-bucket for extras. Accommodation: `house` `pitch` `room` `berth` `apartment` `other` Extras: `Amenity` `Upgrade` `Package` Source: Checkout portal: accommodation semantic segment or extras bucket. Availability/property search: accommodation semantic segment.
`item_category3`		if available	PMS extra type for extras only. `tourist_taxes` `cleaning` `parking` Source: Checkout portal extras only: cost extra_type. Not set for accommodations, packages, or availability/property search.
`item_variant`	`single_night`	if available	Stay duration category for the accommodation. `single_night` - 1 night `weekend` - 2-3 nights incl weekend `midweek` - 2-4 nights without weekend `week` - 6-8 nights or 5 nights incl weekend `extended_stay` - 9-13 nights `long_stay` - 14+ nights Source: Checkout portal accommodations and CMS availability items; derived from arrival/departure.
`item_list_id`	`cart`	if available	ID of the list where the item is shown. Source: Availability/property search list id (availability_search/property_search). Cart/checkout events may supply list id like Cart or Checkout.
`item_list_name`	`Cart`	if available	Name of the list where the item is shown. Source: Availability/property search list name (Availability search/Property search). Cart/checkout events may supply list name like Cart or Checkout.
`item_country`	`Netherlands`	if available	The country where the administration is located. Source: Administration country from BEX (shared across checkout portal and availability/property search).
`item_region`	`Twente`	if available	The region where the administration is located. Source: Administration region from BEX (shared across checkout portal and availability/property search).
`item_city`	`Enschede`	if available	The city where the administration is located. Source: Administration city from BEX (shared across checkout portal and availability/property search).
`administration_id`	`321321`	if available	The ID of the administration in BEX PMS. Source: Checkout portal: BEX administration id. Availability/property search: the same BEX administration id (Booking Experts administration mapping). Notes: Renamed from park_id in legacy CMS/PMS payloads.
`administration_name`	`Administration Name`	if available	The name of the administration in BEX PMS. Source: Checkout portal: BEX administration name. Availability/property search: the same BEX administration name (Booking Experts administration mapping). Notes: Renamed from park_name in legacy CMS/PMS payloads.
`park_id`	`321321`	if available	Deprecated: use `administration_id`.
`currency`	`EUR`	if available	Deprecated: Use `ecommerce.currency`.
`coupon`	`SUMMER10`	if available	Coupon applied to the item. Source: Coupon code applied to the reservation or order item (first code, if any).
`discount`	`25.0`	if available	Discount applied to the item. Source: Discount amount for the order item.
`price`	`350.0`	if available	Price for the item line (stay total for accommodation). Source: Availability/property search: price for the stay. Checkout portal: order item unit price; accommodation uses stay total derived from booking total minus upgrades.
`quantity`	`1`	if available	Quantity of the item. Source: Order item quantity; otherwise 1.
`index`	`1`	if available	Position of the item in the list. Source: Position in the result list (availability/property search only).
`start_date`	`2026-02-20`	if available	The date of arrival for availability. Source: Stay arrival date or availability start date.
`end_date`	`2026-02-22`	if available	The date of departure for availability. Source: Stay departure date or availability end date.
`google_business_vertical`	`hotel_rental`	if available	Google Ads business vertical for dynamic remarketing (examples: "hotel_rental", "retail"). Source: Remarketing business vertical configured globally; not from booking data.