Migrating from Checkout V2 to V3

Checkout V3 improves upon V2 through alignment of polling and callback responses, improvement of field names, and expanding models related to logistics options to permit more advanced features. This guide takes you through the things you need to change in your existing V2 integration to support Checkout V3.

Initiate Session

CheckoutConfiguration

The field Configuration has been added to InitiateSessionRequest and the following fields have been moved into it:

• customerInteraction
• userFlow
• requireUserInfo
• elements

The elements field replaces the former ContactFields and Address`Fields flags with an enum. They are equivalent according to the following table.

Elements	ContactFields	AddressFields
Full (default)	true	true
PaymentAndContactInfo	true	false
PaymentOnly	false	false

We have also added a new field Countries which allows merchants to specify which countries they support.

CallbackUrl

callbackUrlPrefix has been replaced by callbackUrl so that you send in the whole URL to where you want the "Payment Completed" callback.

Strongly typed fields

The following are now strongly typed:

• customerInteraction
• userFlow

The permitted values for these fields used to be case-insensitive. They are now case-sensitive.

Logistics

The logisticsOption object is now changed to better accommodate more advanced Checkout features. It is now a polymorphic object whose type is determined by which logistics carrier is used. Refer to Swagger for more details.

Polling and callback

The response object from polling and the callback object are now identical.

UserDetails

userDetails has been removed. If requireUserInfo is set to true in session initiation, user info will instead be provided in its own dedicated response object UserInfo.

"userInfo": {
    "sub": string,
    "email": string
}

PaymentDetails

paymentDetails.State is now Authorized with a z instead of Authorised with a s.

Renaming of region to city

billingDetails.region has been renamed to billingDetails.city shippingDetails.region has been renamed to shippingDetails.city

Standardized country name

billingDetails.country and shippingDetails.country were previously derived from the free-text field filled in by the customer. We have now changed this to always be two-letter codes that adhere to the ISO-3166-1 Alpha-2 standard.

Cancel session

The endpoint for canceling sessions has been removed for V3.

To make changes or updates to a session, initiate a new session with the same reference as the previous one. This will automatically cancel the previous session. However, if the customer has initiated the payment by clicking "Complete Purchase" in the checkout window, replacing the Checkout session will not work. In such cases, you can cancel the payment through the ePayment API.