API and SDKsSupport
Final authorization

When integrating Klarna payments, the final authorization is a critical step when the step-up scenario occurs. This guide walks you through the creation of a transaction using the payment_token provided by Klarna.

After the customer completes their purchase via Klarna, the Payment Request transitions to the COMPLETED state. At this point:

  • Klarna returns a payment_token which must be secured through Klarna Webhooks
  • You must use this payment_token to authorize the payment within 60 minutes to finalize the transaction.
  • Successful authorization will generate a payment_transaction_id required for future transaction management.

Important: If you do not authorize within 60 minutes, the transaction will be invalidated​.

The below diagram shows the customer journey and Acquiring Partner workflow, illustrating:

  • The handoff from Klarna to the Partner after purchase.
  • The sequence from receiving the payment token to finalizing the payment​.

The acquiring partner must use the payment_token to perform a second call to Klarna's Payment Authorize API.

Path

Parameter nameDescription
partner_account_idThe unique identifier of the Partner account. This is used to scope the request.

Header

Parameter nameDescription
Klarna-Payment-TokenThe payment_token received as part of the step-up scenario.

Body

Parameter nameDescription
currencyCurrency in ISO 4217 format (e.g., "USD")​.
request_payment_transactionRepresents a request to authorize a payment transaction, this object contains the following parameters:
  • amount to authorize (in minor units, e.g., cents)

Sample Request

The payment_token must be passed in the Klarna-Payment-Token HTTP header​.

JSON
{
  "currency": "USD",
  "request_payment_transaction": {
    "amount": 11800,
    "payment_transaction_reference": "acquiring-partner-transaction-reference-1234"
  }
}

Upon successful authorization, the response body includes the payment_transaction_id, which you'll use for payment management actions​.

  • The endpoint is idempotent, so repeated requests with the same token return the same result, ensuring safe retries​.

The response will contain a payment_transaction_response object with the following parameters:

Body

Parameter nameDescription
resultThe result parameter which specifies the outcome of the authorization.
In case of a successful Authorization the result will be set to APPROVED
payment_transactionThe payment_transaction object represents a single payment transaction
This object is only returned if the payment_transaction_response.result is set to APPROVEDThe payment_transaction_id  returned is necessary to manage the Payment Transaction through the Payment Transaction API.

Sample response

JSON
{
  "payment_transaction_response": {
    "result": "APPROVED",
    "payment_transaction": {
      "payment_transaction_id": "krn:payment:eu1:transaction:6debe89e-98c0-[...]",
      "payment_transaction_reference": "acquiring-partner-transaction-reference-1234",
      "amount": 11800,
      "currency": "USD",
      "payment_funding": {...},
      "payment_pricing": {...}
  • Subscribe to Klarna webhook events.
  • Capture and securely store the payment_token.
  • Authorize the transaction within 60 minutes.
  • Handle API responses carefully (support retries thanks to idempotency).
  • Store the payment_transaction_id for managing payments.