Checkout API V3

Klarna provides a number of different callbacks during the customer's checkout session. The callbacks can be used to update the order when the customer changes their address as well as to do a final check to validate the order before it is submitted. The callbacks are sent as POST requests to the endpoint you specify when creating the order. Your response is interpreted using the response code and body. Read more on [here](https://docs.klarna.com/kco/).