Token creation - Authorize the payment

Steps for token creation only or for token creation with purchase:

1. 1.
   Customer clicks on the Klarna Payment button
2. 2.
   The javascript function attached to the button click handler initiate is triggered
3. 3.
   The Partner sends a request to the Acquiring Partner containing interoperability_token and interoperability_data for:

   1. 3.1.
      Token creation only (Use cases: On-demand without a purchase, Subscription with free trial)
   2. 3.2.
      Token creation with purchase (Use cases: On-demand with initial purchase, Subscription without free trial, Mixed payments)
4. 4.
   The Acquiring Partner forwards the required payment context data to Klarna’s Payment Authorization API including:

   • 4.1.
     supplementary_purchase_data

     • 4.1.1.
       ondemand_service or
     • 4.1.2.
       subscription
   • 4.2.
     step_up_config
   • 4.3.
     request_customer_token
   • 4.4.
     if purchase is applicable: request_payment_transaction
5. 5.
   Klarna returns one of the following responses:

   • 5.1.
     STEP_UP_REQUIRED – The customer has to authenticate for the token creation and, if applicable, for the payment. Either return the Klarna payment_request_id or payment_request_url to the Partner.
   • 5.2.
     APPROVED – Successful creation of the customer token and, if applicable, the payment transaction.
   • 5.3.
     DECLINED – Token creation and payment authorization is declined.
6. 6.
   The javascript function attached to the initiate button click handler returns a promise resolving to the authorization result

As described in the previous section, once the customer has selected the Klarna payment option in the payment selector, the Acquiring Partner will need to render the Klarna Payment Button.

The Acquiring Partner will need to configure paymentButton component from the paymentPresentation instance with the following attributes:

• initiate button click handler: attach a function which triggers your backend to call Klarna’s Payment Authorize API and return a promise resolving to the authorization result.
• initiationMode: This parameter controls how the Klarna Purchase Journey is launched (redirect / pop up window) on different devices (mobile/desktop/native)

Sample code

async function initiateKlarnaPayment(klarnaNetworkSesionToken, paymentOptionId) {
  try {
    // 1) Ask your backend to authorize the payment
    const response = await fetch('/api/authorize-payment', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ klarnaNetworkSesionToken, paymentOptionId })
    });

    if (!response.ok) throw new Error('Network or server error');

    // 2) Handle backend response

To support tokenized payments, Acquiring Partners must include additional parameters when calling the Authorization API. Klarna then generates a customer token, which authorizes future payments on behalf of the customer. Each customer token is issued with specific scopes that define the permitted actions and level of access for subsequent transactions.

{
  "currency": "USD",
  "supplementary_purchase_data": {
      "subscriptions": [{
        "subscription_reference": "MONTHLY PLAN",
        "name": "9.99 for spotify",
        "free_trial": "ACTIVE",
        "billing_plans": [{
            "billing_amount": 999,
            "currency": "USD",
            "from": "2025-08-01",
            "interval": "MONTH",

{
  "currency": "USD",
  "supplementary_purchase_data": {
      "subscriptions": [{
        "subscription_reference": "PREMIUM_INDIVIDUAL",
        "name": "9.99 for spotify",
        "free_trial": "INACTIVE",
        "billing_plans": [{
            "billing_amount": 999,
            "currency": "USD",
            "from": "2025-08-01",
            "interval": "MONTH",

The Payment Authorize API response for the payment_transaction_response and for the customer_transaction response can yield 3 different results:

When the customer has to authenticate for the token creation, and optionally also for the purchase completion, the Step-up scenario will be triggered and the Acquiring Partner will receive a STEP_UP_REQUIRED result.

In such scenario, the Payment Authorization API returns a Payment Request in the response. The expectation is that the customer will go through Klarna’s Purchase Journey to authenticate for the token creation and, if required, to complete the purchase. The required steps to properly make the step-up scenario work is outlined in the next section.

The following parameters are present in the response to the request.

Token creation with purchase -Sample response - STEP_UP_REQUIRED

{
  "payment_transaction_response": {
    "result": "STEP_UP_REQUIRED"
  },
  "customer_token_response": {
    "result": "STEP_UP_REQUIRED"
  },
  "payment_request": {
    "payment_request_id": "krn:payment:eu1:request:552603c0-fe8b-4ab1-aacb-41d55fafbdb4",
    "payment_request_reference": "acquiring-partner-request-reference-1234",
    "amount": 11800,
    "currency": "USD",

Token creation without purchase -Sample response - STEP_UP_REQUIRED

{
  "customer_token_response": {
    "result": "STEP_UP_REQUIRED"
  },
  "payment_request": {
    "payment_request_id": "krn:payment:eu1:request:552603c0-fe8b-4ab1-aacb-41d55fafbdb4",
    "payment_request_reference": "acquiring-partner-request-reference-1234",
    "amount": 11800,
    "currency": "USD",
    "state": "SUBMITTED",
    "expires_at": "2025-01-02T13:00:00Z",
    "created_at": "2025-01-01T12:00:00Z",

When the token creation is successful, a customer_token is created on the Klarna Network. Optionally, if a purchase is completed, a payment_transaction_id is created too. No further customer interactions are needed and the Acquiring Partner can directly inform their partners that the payment session is completed and that the customer can be redirected to the confirmation page.

Acquiring Partners must share the Klarna customer_token or issue their own token equivalent and share it with their Partners to enable them to perform future token charges. Acquiring Partners must also store the Klarna payment_transaction_id for future operations on the transaction through the Payment Transactions API, such as capture and refund. The Acquiring Partner will receive the following parameters in the response.

Sample response - APPROVED

{
  "customer_token_response": {
    "result": "APPROVED",
    "customer_token": "krn:customer-token:123"
  }
}

Sample response - APPROVED

{
  "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": {...}
    }
  },

If a token creation request, optionally with a purchase, could not be approved by Klarna and the step-up scenario cannot be triggered (due to missing configuration or a permanent decline), the Acquiring Partner will receive a DECLINED result. Declines should not be replayed without a change of context. The Acquiring Partner should inform the Partner that the token creation, and the transaction if applicable, could not be completed.

Sample response - DECLINED

{
  "customer_token_response": {
    "result": "DECLINED"
  }
}

Sample response - DECLINED

{
  "payment_transaction_response": {
    "result": "DECLINED"
  },
  "customer_token_response": {
    "result": "DECLINED"
  }
}

When creating a token with a purchase, it’s possible—though rare—for the payment transaction and customer token results to differ. The list below summarizes each scenario and the appropriate next steps:

• APPROVED (transaction), STEP_UP_REQUIRED (token): Register payment_transaction_id, then direct the customer to the step-up flow to complete token authentication.
• STEP_UP_REQUIRED (transaction), APPROVED (token): Register customer_token, then direct the customer to the step-up flow to complete the purchase.
• APPROVED (transaction), DECLINED (token): Retrieve payment_transaction_id; token creation failed—notify the partner to inform the transaction.
• DECLINED (transaction), APPROVED (token): Retrieve and save customer_token for future use; purchase failed—notify the partner to inform the customer. May use the customer_token to reattempt the charge on the background if customer_not_present scope was requested.

Back to the SDK, the function attached to the initiate handler returns a promise which should resolve to an object that varies depending on the transaction outcome:

• Step-up scenario

  • The object contains a paymentRequestId generated as part of the step-up response.
  • When the customer clicks the Klarna payment button, the Klarna Purchase journey is triggered.
  • This flow is described in more detail in the Handle Step-up section.
• Immediately approved transaction

  • The object may include an optional returnUrl that redirects the customer to the order confirmation page.
  • In this case, the transaction is approved right after the customer clicks the Klarna payment button.
• Declined transaction

  • The object may include an optional returnUrl that redirects the customer after the decline.
  • The Acquiring Partner should inform the Partner that the transaction could not be completed.
  • The Partner should then prompt the customer to select another payment method.

const buttonConfig = {
  initiate: () => {
    //call to Klarna Payment Authorize API returns STEP_UP_REQUIRED
    return { paymentRequestId: "krn:payment:eu1:request:5eb1.." }
  },
  initiationMode: "DEVICE_BEST",  // Device-optimized payment initiation
}

// Render and mount the button with the assigned configuration
paymentPresentation.paymentButton.component(buttonConfig).mount("#klarna-button-container");