form[data-next-checkout] is the checkout: its fields are checked as the shopper types, kept in this tab, and sent with the order on submit. checkout.* reads what was entered, for a review step, and checkout.errors.<field> each field's message.
One checkout in this tab, the same across its steps, reloads and a return from a payment gateway; a new one after an order is paid. Empty until checkout.started.
step
number
optional
The step of a multi-step checkout (data-next-checkout-step), from 1; none on a one-page checkout.
When billing_same_as_shipping is false, from address.entered for it on.
payment_method
string
optional
The API's code for the chosen payment method, on a checkout page: card_token, paypal, apple_pay, …
Cart
The cart every cart.* event carries. Prices are numbers in currency, there once the server priced these lines: total = subtotal − total_discount + shipping_method.price.
The discounts on shipping, such as a free-shipping offer.
Discount
A discount on the cart's products or on its shipping. Amounts are in the cart's currency.
Field
Type
Present
name
string
always
The offer's name.
amount
number
always
The amount taken off.
source
"offer" | "coupon"
always
coupon for a code the shopper entered (it is in coupons); offer for an automatic offer or a bundle card's own code.
code
string
optional
The code, for a coupon.
offer_id
number
always
The offer that gave it.
percentage
number
optional
The percentage the offer is set to take off, as the API reports it, such as 20. Its configured value, for a label such as “20% off”; the amount actually taken off is amount.
Subscription
A package billed again every interval.
Field
Type
Present
interval
"day" | "month"
always
The unit of the renewal interval.
interval_count
number
always
How many intervals between renewals.
price
number
priced
What each renewal charges, after discounts.
original_price
number
priced
What each renewal charges before discounts.
Field
Is
checkout.errors.<field>
The message of a field the checkout refused; payment for the payment