Token charge Customer Present - Final authorization

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

• Klarna returns a klarna_network_session_token which must be secured through Klarna Webhooks
• You must use this klarna_network_session_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.

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 Klarna Network session token to finalizing the payment​.

After receiving the klarna_network_session_token from Klarna, call the Payment Authorize API to finalize the authorization. Pass the token in the Klarna-Network-Session-Token request header.

This request is performed entirely on the backend and does not involve customer interaction. As a result, the step_up_config object can be omitted.

Submit the same request payload that was used in the initial authorization request.

The klarna_network_session_token acts as an idempotency key. Repeating the request with the same token returns the same result, which allows safe retries.

In the request to the Payment Authorize API, specify the following parameters:

curl https://api-global.test.klarna.com/v2/accounts/{partner_account_id}/payment/authorize \
  -H 'Authorization: Basic <API key>' \
  -H 'Klarna-Network-Session-Token: ***' \
  -H 'Content-Type: application/json' \
  -d '{
        "payment_request_id": "krn:payment:eu1:request:552603c0-fe8b-4ab1-aacb-41d55fafbdb4",
        "currency": "USD",
        "request_payment_transaction": {
          "amount": 11800,
          "payment_option_id": "***",
          "payment_transaction_reference": "finalize-ref-1234"
        },

When the integration is implemented correctly, Klarna approves the authorization and returns a payment_transaction. Klarna validates that the authorized payment amount matches the amount approved by the customer during the step-up flow.

If the supplementary_purchase_data differs materially from the data previously provided, Klarna may decline the authorization based on its risk assessment.

The result field can have the following values:

Handle this result when Klarna authorizes the payment without requiring customer interaction.

• Read the payment_transaction from the response.
• Store the payment_transaction_id.
• Return a success response to the Partner.
• Continue with post-purchase operations (for example, capture or refund) using the Payment Transactions API.

Sample payload

{
  "payment_transaction_response": {
    "result": "APPROVED",
    "payment_transaction": {
      "payment_transaction_id": "krn:payment:eu1:transaction:6debe89e-98c0-[...]",
      "payment_transaction_reference": "transaction-reference-1234",
      "amount": 11800,
      "currency": "USD",
      "payment_funding": {
        "type": "INVOICE",
        "details": { }
      },

Handle this result when Klarna rejects the authorization.

• Do not retry the authorization unless explicitly instructed by Klarna.
• Return a failure response to the Partner.
• End the payment flow.

Sample payload

{
  "payment_transaction_response": {
    "result": "DECLINED",
    "result_reason": "PAYMENT_DECLINED"
  }
}