Integration Guide of HPP with Klarna Payments

This guide will lead you through all the steps required to accept payments with Klarna Payments using the Hosted Payment Page. At the end you will be able to accept payments with Klarna without hosting any web component on your own pages.

Is HPP the right thing for my integration ?

The Hosted Payment Page (HPP) is a service that lets you use Klarna to accept payments without the need of integrating our products in your web pages, or even without having any consumer fronting website for In-store or Telesales use cases. Learn more about HPP use cases

Ecosystem

Sequence diagrams

You will find here the usual integration flow of the Hosted Payment Page using a Klarna Payments session. In this flow, actors are defined as follow:

  • Consumer: a physical person that wants to buy something.
  • Browser: the browser that the Consumer is able to control, for example on a desktop or a mobile.
  • Merchant Backend: your backend that will do the API calls to HPP, KP and Order Management.
  • HPP: the Hosted Payment Page API
  • Klarna Payments: the Klarna Payments API

Sequence where you host a part of the Consumer flow

  1. Your consumer wants to proceed to a payment using one of Klarna’s payment methods: depending on the integration, this interaction can be on a website when the Consumer choose to pay with Klarna, with a telesales by phone…

  2. Create sessions on Klarna Payments and Hosted Payment Page

a. Create a Payment session on Klarna Payments: After receiving this consumer intent, create a Payment session with Klarna Payments API.

b. Associate the Payment session to an Hosted Page session: Using the session identifier provided by Klarna Payments API, create the corresponding HPP session.

  1. Distribution of the Payment session to your consumer

    a. Distribution can be done by yourself, using a redirection URL given by HPP.

    b. Request that HPP distribute the Payment session directly to your Consumer.

  2. [Invisible step for you] Consumer gets to Hosted Payment Page: Consumer goes to the Payment page using the received link, either by you or by SMS/Email received from Klarna.

  3. [Invisible step for you] Authorization of payment: When the Consumer presses the buy button on the Payment page, payment authorization will be given to the Consumer. HPP will proceed to the redirection of the Consumer to your Backend using the URL given in the session creation.

  4. Confirmation and Authorization Token

    a. Redirection of the Consumer after a successful authorization: The Consumer’s browser is redirected to your Backend, the address contains an Authorization Token that you will need to use to place the order if the order is still valid.

  5. Place the order: When everything has been validated on your side, your backend needs to place the order using the Authorization Token. This returns you an order identifier that will be needed to capture the payment.

  6. Confirmation of the order: You should show the customer that the payment authorization is successful and that the order has been validated.

  7. [This step can be asynchronous] Capture payment: When you want the payment to actually happen, usually when goods are shipped, use the Order Management API to capture the amount on the order. When creating the KP Session, you can also ask the capture to be automatic.

Success flow

After a successful authorization, the Consumer’s browser will be redirected to your success URL defined when you created the HPP session (see Step 3).

HPP will use merchant_urls.success to generate the URL, it should contain the authorization_token but can also use some additional parameters. Please see HPP Create Session Parameters and Options for dynamic parameters.

Rejection and cancellation flows

When the Consumer decides to abort the process or gets rejected by Klarna for payment authorization, the Consumer’s browser is redirected to one of the URLs defined when you created the HPP session (see Step 3).

  • merchant_urls.failure: Consumer is redirected there after being refused by Klarna.
  • merchant_urls.cancel: Consumer is redirected there after clicking on the Cancel button.

Please see HPP Create Session Parameters and Options for dynamic parameters.

Alternative Sequence: no hosting of the Consumer flow

This alternative sequence is almost the same except that you don’t need to host any page that should be shown to the Consumer. As you can’t rely on any redirection to get the status of the session, your backend needs to poll the HPP API to get it.

You can decide whether you want to host these pages by yourself or rely on HPP ones by defining the merchant_urls. You can give HPP a success url but not a cancellation one.

  1. Confirmation and Authorization Token

    b. Polling to get the successful authorization: The Consumer’s browser is shown a simple payment confirmation page, your Backend will need to get the Authorization Token using HPP API. that you will need to use to place the order if the order is still valid.

Success flow

After a successful authorization, the read session endpoint will give you the status of the Session and the Authorization Token to place the order with.

Rejection and cancellation flows

When the Consumer decides to abort the process or gets rejected by Klarna for payment authorization, the status of the session will also be updated. The Consumer will see a simple cancel or rejection page.

Step by step integration

1. Create KP Session with the Payments API

The first step is to create a KP Session with the Klarna Payment API in order to be able to host it using the Hosted Payment Page API. This is where you are going to define all you know already about your Consumer, what is the content of the order and the metadata associated to the purchase.

This call corresponds to Step 2a in the sequence diagram.

DescriptionCreates a session with KP-API
Description
Reference
Creates a session with KP-API
For a full list of accepted (optional) parameters, possible returns and error codes you can reference the KP-API documentation
Description
Url structure
Creates a session with KP-API
https://{endpoint}/payments/v1/sessions
Description
Example
Creates a session with KP-API
curl -X POST https://<endpoint>/payments/v1/sessions --header "Authorization: Basic <token> " --header "Content-Type: application/json" --header “Cache-Control: no-cache” --data “<parameters>”

Create a session KP: Request

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{
    "purchase_country": "us",
    "purchase_currency": "usd",
    "locale": "en-US",
    "order_amount": 20000,
    "order_tax_amount": 0,
    "order_lines": [
        {
            "image_url": "https://www.exampleobjects.com/logo.png",
            "type": "physical",
            "reference": "Could be a Product Id or SKU #",
            "name": "Cool Bike",
            "quantity": 1,
            "unit_price": 20000,
            "tax_rate": 0,
            "total_amount": 20000,
            "total_discount_amount": 0,
            "total_tax_amount": 0
        }
    ],
    "billing_address": {
        "given_name": "John",
        "family_name": "Doe",
        "email": "email+require_signup@example.com",
        "title": "Mr",
        "street_address": "2425 Example Rd",
        "street_address2": "",
        "postal_code": "43221",
        "city": "Columbus",
        "region": "OH",
        "phone": "6145675309",
        "country": "US"
    }
}

Create a session KP: Response

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{
    "session_id" : "<kp_session_id>",
    "client_token" : "<JWT>", // Ignore this field when using KP with HPP
    "payment_method_categories": [
        {
            "identifier": "pay_later",
            "name": "Pay later.",
            "asset_urls": {
                "descriptive": "https://cdn.klarna.com/1.0/shared/image/generic/badge/en_gb/pay_later/descriptive/pink.svg",
                "standard": "https://cdn.klarna.com/1.0/shared/image/generic/badge/en_gb/pay_later/standard/pink.svg"
            }
        }
    ]
}

How to create the Request

Please read the session creation guide of Klarna Payments API to get all details on fields and how you can use them. As you will use the Hosted Payment Page API to host your KP Session, you don’t need to read the step after.

As you won’t own and host the page that displays Klarna Payments’ Client, you have to respect additional guidelines that will depend on the use case of your integration see see special rules .

Depending on your integration use case (ie eCommerce, In Store or Telesales), you may have to respect some guidelines when creating the KP Session, see special rules .

How to interpret the Response

The KP Session is created on a successful response. On the fields present in it, only the session_id is useful when KP is used with Hosted Payment Page API. You will have to use it to build HPP’s payment_session_url.

https://api.klarna.com/payments/v1/sessions/<kp_session_id>

2. Create HPP Session with Hosted Payment Page API

The second step is to create the HPP Session using the KP Session you have just created. Sessions will have a tied lifecycle meaning that the HPP Session will expire 1 hour before the KP Session, see session lifetimes . Multiple HPP Sessions can be linked to the same KP Session if you need to have multiple customization at the same time, although it is considered as a bad practice.

This call corresponds to Step 2b in the sequence diagram.

How to create the Request

Please read the session creation call reference of HPP to get all details on fields and how you can use them. As you will use the Hosted Payment Page API to host a KP Session, you have additional options that you can use.

Specific Klarna Payments parameters when creating an HPP Session

Payment Methods and Categories

HPP lets you define what Payment Method Categories should be made available to the Consumer when seeing the Klarna Payment Widget on HPP. Payment Categories are Pay Now, Pay Later or Slice It (Pay over time), and will differ depending on what Products are available for you at Klarna. When you create a KP Session in Step 2a, Klarna Payments API sends you back as a result all available payment categories for the KP Session. You have to use this values to configure the HPP Session.

Initial display options

This parameter will define what the Consumer will when first loading the Payment Page.

  1. Display only one Payment Method Category using the field payment_method_category
  2. Display a defined list of Payment Method Categories using the field payment_method_categories
  3. Display all available Payment Method Categories by omitting both parameters

Defining both fields payment_method_category and payment_method_categories at the same time will end up in a refused request.

1. Display only one Payment Method Category

Keypayment_method_category
Key
Description
payment_method_category
Consumer will be able to select a Payment Method from a single Category. The value has to be one of the payment categories sent back by KP API when creating the KP Session.
Key
Type
payment_method_category
Enum
Key
Accepted Values
payment_method_category
PAY_NOW, PAY_LATER, PAY_OVER_TIME, DIRECT_DEBIT, DIRECT_BANK_TRANSFER
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{
    "options": {
        "payment_method_category": "pay_later"
    }
}

2. Display a list of Payment Method Categories

Keypayment_method_categories
Key
Description
payment_method_categories
Consumer will be able to select a Payment Method from a list of Categories. Values have to be one of the payment categories sent back by KP API when creating the KP Session.
Key
Type
payment_method_categories
List values from an Enum
Key
Accepted Values
payment_method_categories
PAY_NOW, PAY_LATER, PAY_OVER_TIME, DIRECT_DEBIT, DIRECT_BANK_TRANSFER
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{
    "options": {
        "payment_method_categories": [
            "pay_later",
            "pay_now"
        ]
    }
}

3. Display all available Payment Method Categories

When none of the above parameters are given on the create call, all the available payment categories will be made available to the consumer.

Fallback flow option

When activated, the Fallback flow will make sure that the Consumer is declined for all payment categories of the KP Session before going through the Rejection flow. In combination with the two first initial display options, it is possible to activate a fallback flow that will happen only when the Consumer is declined for the payment categories that were defined. This fallback works as follow:

  1. The KP Session is created and Pay Now, Pay Later and Slice It are all available
  2. The HPP Session is created with the Slice It category because the Consumer’s choice has been made before going to HPP
  3. The Consumer arrives on the Payment Page and sees only Slice It options. The Consumer applies for one of the Slice It options and for some reason gets declined
    1. The fallback flow isn’t activated (default behavior) or has already happened, the Consumer will go through the Rejection flow.
    2. The fallback flow is active, the Consumer will see all other options that are still available (Pay Now, Pay Later). The Consumer can then apply again.

The fallback flow may be transparent for the Consumer and is not a guarantee of authorization. The Consumer may be declined for additional payment method categories while applying for one.

Keypayment_fallback
Key
Description
payment_fallback
When true, the Fallback flow will make sure that the Consumer is declined for all payment categories of the KP Session before going through the Rejection flow.
Key
Type
payment_fallback
Boolean
Key
Accepted Values
payment_fallback
true, false
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{
    "options": {
        "payment_method_categories": [
            "pay_later",
            "pay_now"
        ]
    }
}

3. Distribute Session with HPP (Optional)

Outside of typical eCommerce flow, you will need to distribute the link to the Hosted Payment Page to the Consumer, for example by email or SMS, or by QR code. The Consumer will then be able to access the page and complete the payment.

This call corresponds to Step 3b in the sequence diagram.

Read our guide on how to distribute the HPP Session

4. Retrieve the Authorization Token

As described in the objects overview , when a Consumer gets a Payment Authorization, your backend will need to use a KP Authorization Token to place the Order.

This token can be retrieved by your system using two different ways, via the redirection of the Consumer to your own website or by making an API Call to get the status of the session.

It is advised to use both method to make sure that your system is actually placing the order whenever the Consumer has gotten a confirmation of payment by Klarna.

4.a. From the Consumer redirection

This token is given to you via the redirection of the Consumer to your own website. When configuring the merchant_urls.success at the creation of the HPP Session, you had to place a place holder to retrieve it back. You just need to extract the value from there.

This call corresponds to Step 6a in the sequence diagram.

4.b. From the HPP Session Status

This token can be retrieved by making a read session call to the HPP API or registering for callback . You can for example use a polling mechanism to check the status of the session and when the Consumer gets an authorization, you will be able to extract the KP Authorization Token from the server response.

Please read our track session status guide to get all details on how you can get the status of the session. When the status is changed to COMPLETED, you will be able to read the authorization_token.

5. Place Order with Klarna Payments API

Now that the Consumer has gotten an Authorization from Klarna for the Payment, you have to use the Authorization Token that you retrieved in the redirection to Place the Order. After this call, Klarna will consider that the Order is actually valid and that you will be able to capture the payment when the goods are being delivered. Please read the place order guide of Klarna Payments to get all details.

Depending on your integration use case (ie eCommerce, In Store or Telesales), you may have to respect some guidelines when placing the order, see special rules .

To ease your integration and depending on your use case, you can count on the auto_capture feature of the KP API to automatically capture the order after its creation. Please read the place order guide of Klarna Payments to get all details.

This call corresponds to Step 7 in the sequence diagram.

Place order request

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{
  "purchase_country": "GB",
  "purchase_currency": "GBP",
  "locale": "en-GB",      
  "order_amount": 57064,
  "order_tax_amount": 9511,
  "order_lines": [
    {
      "image_url": "https://www.exampleobjects.com/logo.png",
      "type": "physical",
      "reference": "Could be a Product Id or SKU #",
      "name": "Cool Bike",
      "quantity": 1,
      "unit_price": 20000,
      "tax_rate": 0,
      "total_amount": 20000,
      "total_discount_amount": 0,
      "total_tax_amount": 0
    }
  ]
}

Place order response

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{
  "order_id": "41c001ca-f6d4-4240-bbc5-5d2c036a2de4",
  "fraud_status": "ACCEPTED"
}

6. Capture Payment with Order Management API

After the creation of the Order, if you haven’t used the auto_capture feature of the KP API, you will need to capture the payment using the Order Management API. Until this step has been done, the payment is not really finalized and the payment won’t occur.

Please read the capture guide of Order Management to get all details.

Edge cases

Disabling an HPP Session by Merchant initiative

If for any reason the payment session has to be canceled (expiration of an offer, order was paid using another payment method, etc), the HPP API gives to the Merchant the possibility to disable an HPP Session. To do that, it is required to send a delete request on the HPP Session resource.

Please read the disable session call reference of HPP