This section of the guide walks you through initiating a payment and letting your customers pay with Klarna.
When your customer wants to pay with Klarna, you have to open a payment session and share the shopping cart details in a POST request to the {apiURL}/payments/v1/sessions endpoint. In that request, you also specify if the payment is one-time or recurring.
Once you start a payment session, it stays open for 48 hours or until you place an order. You can also send a separate POST request to cancel the session.
Klarna payments API uses HTTP basic authentication. To authenticate, use your API credentials that consist of:
If you're using an API platform that lets you store your credentials, you can add them in relevant fields. Otherwise, make sure to include the Base64-encoded username:password in the Authorization header field of each API request, as shown below.
Authorization: Basic pwhcueUff0MmwLShJiBE9JHA==
A sample authorization request header with Base64-encoded credentials.
To get a success response, include the following required parameters in your POST {apiURL}/payments/v1/sessions request.
Parameter | Description |
---|---|
locale | The language of information presented on the Klarna widget. Learn more about using locale in API calls. |
purchase_country | The country where the purchase is made. Learn more about supported countries. |
purchase_currency | The currency in which the customer is charged. Learn more about supported currencies. |
order_amount | The total price of the order, including tax and discounts. |
order_lines | The details of order lines in the purchase. |
intent | The purpose of the payment session. |
merchant_urls.authorization | Get a callback once the customer has completed the flow and you can create an order. |
We recommend you don't include customer details when initiating a payment session. Instead, use the authorize()
call to share them with Klarna at a later stage of the checkout process when the customer clicks Buy.
As we already mentioned, you can use Klarna payments in a variety of payment scenarios. Depending on the scenario, add the right value in the intent field of the request.
For one-time payments, set intent to buy.
For recurring payments:
The intent you set for a session determines the steps you need to take when creating an order later in the process.
To open a one-time payment session, include all common parameters in the request body and set intent to buy.
{
"acquiring_channel": "ECOMMERCE",
"intent": "buy",
"purchase_country": "SE",
"purchase_currency": "SEK",
"locale": "en-SE",
"order_amount": 9500,
"order_tax_amount": 1900,
"order_lines": [
{
A sample POST request to create a one-time payment session.
To enable recurring payments without charging your customer at checkout, include the following in your request:
You can charge the customer later using a customer token created in the same Klarna payments session.
{
"acquiring_channel": "ECOMMERCE",
"intent": "tokenize",
"purchase_country": "SE",
"purchase_currency": "SEK",
"locale": "en-SE",
"order_amount": 9999,
"order_tax_amount": 2000,
"order_lines": [
{
A sample POST request to enable recurring payments.
To charge the customer at checkout and enable recurring payments at the same time, include the following in your request:
{
"acquiring_channel": "ECOMMERCE",
"intent": "buy_and_tokenize",
"purchase_country": "SE",
"purchase_currency": "SEK",
"locale": "en-SE",
"order_amount": 9999,
"order_tax_amount": 2000,
"order_lines": [
{
A sample POST request to charge the customer at checkout and enable recurring payments.
Mixed payments allows you to charge the customer at the checkout for one item and enable future orders by tokenizing another payment method.
You will be able to charge the customer later using a customer token.
In response to a create session call, you receive:
{
"session_id": "068df369-13a7-4d47-a564-62f8408bb760",
"client_token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6IjAwMDAwMDAwMDAtMDAwMDAtMDAwMC0wMDAwMDAwMC0wMDAwIiwidXJsIjoiaHR0cHM6Ly9jcmVkaXQtZXUua2xhcm5hLmNvbSJ9.A_rHWMSXQN2NRNGYTREBTkGwYwtm-sulkSDMvlJL87M",
"payment_method_categories": [
{
"identifier": "klarna"
"name" : "Pay with Klarna",
"asset_urls" : {
"descriptive" : "https://x.klarnacdn.net/payment-method/assets/badges/generic/klarna.svg",
"standard" : "https://x.klarnacdn.net/payment-method/assets/badges/generic/klarna.svg"
A sample success response to the create session call.
If your request doesn't pass our validation, you'll receive an error response.
{
"correlation_id": "6a9b1cb1-73a3-4936-a030-481ba4bb203b",
"error_code": "BAD_VALUE",
"error_messages": [
"Bad value: order_lines"
]
}
A sample error response caused by incorrect order line details.
Go to Error Handling to learn more about common errors and troubleshooting suggestions. You can use the value in correlation_id to find entries related to the request under Logs in the Merchant portal.