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What is Klarna?

Klarna is a buy now, pay later (BNPL) payment method that offers flexible payment options and supports recurring payments. This allows for accepting recurring payments and giving buyers more flexible ways to pay.

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Sign-up

A Klarna account can be requested from the Klarna Business Portal.

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Credentials

To connect a Klarna account, obtain the following credentials from the Klarna Business Portal.
  • Username: An API username which can be generated by navigating to Preferences → Settings → Manage Klarna API Credentials.
  • Password: An API password which can be generated by navigating to Preferences → Settings → Manage Klarna API Credentials.
  • Region: The region of the Klarna account. This can be Europe, North America, or Oceania.

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Supported countries and currencies

Klarna supports transactions from buyers in AT, AU, 17 more. Klarna supports processing payments in AUD, CAD, 8 more.

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Subscriptions (MIT)

Klarna can be used to:
  1. Store the buyer’s Klarna payment method during the first (customer-present) payment, and
  2. Charge future subscription renewals as merchant-initiated transactions (MIT) using the saved payment method - typically with no redirect.
This is the recommended approach for recurring subscriptions.

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When to use this flow

Use this flow when:
  • A customer approves Klarna once during sign-up or checkout, and
  • they need to be charged again later for subscription renewals without requiring them to re-authenticate each time.

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Prerequisites

  • A Klarna payment service needs to be configured for the merchant account.
  • Webhooks need to be configured for the Klarna payment service (required for tokenization).

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How it works

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Step 1. First payment (customer present)

On the initial subscription payment:
  • Use Klarna as the payment method
  • Provide a redirect_url so the customer can complete Klarna approval
  • Set store: true so the Klarna payment method is saved for the buyer
Example request
using Gr4vy;
using Gr4vy.Models.Components;

// Load your private key from disk, env, or your secret manager
var privateKey = "...";

var sdk = new Gr4vySDK(
    id: "example",
    server: SDKConfig.Server.Sandbox,
    bearerAuthSource: Auth.WithToken(privateKey),
    merchantAccountId: "default"
);

var res = await sdk.Transactions.CreateAsync(transactionCreate: new TransactionCreate() {
    Amount = 5000,
    Currency = "USD",
    Country = "US",
    PaymentMethod = new PaymentMethodRequest() {
        Method = "klarna",
        RedirectUrl = "https://yourapp.com/callback",
        Country = "US",
        Currency = "USD"
    },
    Store = true,
    PaymentSource = "recurring",
    MerchantInitiated = false,
    IsSubsequentPayment = false,
});
// handle response

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Step 2. Subscription renewals (merchant initiated)

For each renewal:
  • Use the saved payment method ID by setting method to "id"
  • Mark the transaction as a subsequent recurring payment and merchant-initiated
Example request
using Gr4vy;
using Gr4vy.Models.Components;

// Load your private key from disk, env, or your secret manager
var privateKey = "...";

var sdk = new Gr4vySDK(
    id: "example",
    server: SDKConfig.Server.Sandbox,
    bearerAuthSource: Auth.WithToken(privateKey),
    merchantAccountId: "default"
);

var res = await sdk.Transactions.CreateAsync(transactionCreate: new TransactionCreate() {
    Amount = 5000,
    Currency = "USD",
    Country = "US",
    PaymentMethod = new PaymentMethodRequest() {
        Method = "id",
        Id = "c2495b14-ca95-4199-87c3-27cbfefcbe9e"
    },
    PaymentSource = "recurring",
    MerchantInitiated = true,
    IsSubsequentPayment = true,
});
// handle response