Switch from Klarna API to Kustom API (Klarna Checkout V3)

This article explains how to switch from the Klarna API and update to the Kustom API.

This does not happen automatically. You must generate new API keys in Kustom and add them to Mystore yourself.

What Does the Message in Kustom Portal Mean?

If you see the message:

Some services are still using Klarna endpoints. Follow this guide to switch your setup to Kustom.

it means that your online store is still using the old Klarna API endpoints (api.klarna.com).

You must:

  • Generate a new API key in Kustom
  • Add it to Klarna Checkout V3 in Mystore
  • Delete the old Klarna API key in Kustom Portal


How to Switch – Step by Step

Step 1: Generate a New API Key in Kustom

Follow these steps (based on Kustom’s Help Center):

  1. Go to Kustom Portal and sign in.
  2. Click Integrations in the left-hand menu.
  3. Click Generate new.
  4. Wait while the key is created.

Once the key has been generated:

  • Copy the Kustom ID (username)
  • Copy the Kustom Secret (password)
  • Store them in a secure location

Important:

The Secret is only displayed once. If you lose it, you must generate a new API key.


Step 2: Add the API Keys in Mystore

  1. Go to Extensions → Your extensions
  2. Open Klarna Checkout V3
  3. Click Credentials
  4. Enter:
    • Kustom ID
    • Kustom Secret
  5. Click Update ID and Secret


Step 3: Delete the Old Klarna API Key

  1. Go back to Kustom Portal → Integrations
  2. Locate the old key (pointing to api.klarna.com)
  3. Click the three dots
  4. Select Delete API key


How to Confirm the Update Is Correct

In Kustom Portal, you should no longer see:

  • api.klarna.com

You should only use:

  • api.kustom.co

The “Action required” message will disappear once the setup is correctly updated.


Important to Know

  • This is not done automatically
  • You must use Klarna Checkout V3
  • If you do not update before the deadline, payments may stop working
  • If you have multiple API keys, ensure you update the correct integration


Troubleshooting

“Integrations” Is Not Visible in the Portal

You likely do not have sufficient permissions.

Solution:

  • Contact your account administrator
  • Request access via User Manager


I Lost the Secret Key

You must:

  1. Delete the existing key
  2. Generate a new API key
  3. Add it again in Mystore


What If This Does Not Solve the Issue?

  • Verify that the correct ID and Secret have been entered
  • Confirm that you are using Klarna Checkout V3
  • Test a new order in your online store
  • Contact Mystore support and include:
    • A screenshot from Kustom Portal
    • A screenshot of the settings in Klarna Checkout V3


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