PSP Onboarding Flow overview - MoR

For partners on a Merchant of Record agreement with Klarna, the flow to onboard a new merchant consists of only two calls as shown in the diagram below.

The first call is a POST call to the /merchant endpoint. This call will return a Merchant ID (MID) that is ready to transact, along with the credentials that this MID should use to authenticate against Klarna's Payments API. This call should include all branding information for this merchant, as well as any data that is required for regulatory compliance purposes.

At this point, the MID is ready to start transacting by calling Klarna's Payments API directly.

At any point in time, the partner can perform a PATCH call to the /merchant/{mid} endpoint to send updated branding information, as well as any additional merchant data that may be required per the partner's agreement with Klarna. Klarna will then update the MID in all internal systems.

Request Headers

Name and Example: Authorization: Basic dXNlcm5hbWU6cGFzc3dvcmQ=

Type: String: "Basic " followed by username:password, encoded using base64

Description: To authenticate and authorize the request.

Name and Example: Klarna-Idempotency-Key: your-custom-identifier-42

Type: Any non-blank String

Description: When an API endpoint is called with the same Klarna-Idempotency-Key twice, the second call will return the exact same response as the first call without any changes being made on the Klarna side.

This is useful when the first call may time out.