Klarna needs to know what the customer is buying. Send the order details when you create the
payment, or Klarna is not offered in the payment window.

Requirements

A payment can be paid with Klarna when it has:

Field	Requirement
`order.basket`	At least one item. Each item needs `name`, `sku`, `price`, `qty` and `vat_rate`.
`order.billing_address.country`	The customer's country as a two-letter code, for example `DK`.

If one of these is missing, the payment window shows the payment's other methods, but not
Klarna.

The basket

Each basket item becomes an order line at Klarna:

Field	Description
`name`	The name the customer sees.
`sku`	Your reference for the item.
`price`	The price of one item, including VAT, in the currency's smallest unit.
`qty`	The number of items.
`vat_rate`	The VAT rate as a decimal, for example `0.25` for 25%.

If you set order.shipping.price, the shipping is added as its own order line.

🚧
The basket must add up to the amount
Klarna checks that the order lines add up to the payment's amount. Make sure that the sum of
price × qty for every item, plus the shipping price, equals amount.

Example

{
  "amount": 23500,
  "currency": "DKK",
  "order_id": "1234",
  "methods": ["klarna"],
  "order": {
    "basket": [
      {
        "name": "T-shirt",
        "sku": "tshirt-blue-m",
        "price": 11250,
        "qty": 2,
        "vat_rate": 0.25
      }
    ],
    "shipping": {
      "method": "own_delivery",
      "price": 1000,
      "vat_rate": 0.25
    },
    "billing_address": {
      "name": "Jane Doe",
      "email": "[email protected]",
      "country": "DK"
    }
  }
}

The basket adds up to 2 × 11250 + 1000 = 23500, which matches amount.