Overview
To successfully call the Solaris XS2A API, you must provide a valid X-Custom-Property-Partner-Id in your request header.
If an invalid, outdated, or unknown Partner ID is used, the API will return an error.
If no X-Custom-Property-Partner-Id header is provided at all, the request will also be rejected.
(Error details will be added here later.)
This happens because the system cannot find a corresponding active PartnerConfiguration for the provided Partner ID, or because the mandatory header is missing entirely.
Where is the authoritative list maintained?
The only authoritative and up-to-date list of valid Partner IDs is maintained in the LIVE environment.
Even if you are integrating or testing in Sandbox, you must retrieve the list of available partners from the LIVE XS2A API.
Do not rely on:
Previously stored Partner IDs
Hardcoded values
Sandbox-only assumptions
Outdated documentation
How do I retrieve the current list?
Send the following request to the LIVE environment:
GET https://xs2a-api.solarisbank.de/psd2/partners
This endpoint returns the currently active and supported Partner IDs for the Solaris PSD2 interface.
What happens if the header is missing?
The X-Custom-Property-Partner-Id header is mandatory for XS2A API requests.
If it is not included in the request:
The system cannot determine the correct partner configuration.
The request will be rejected before processing.
An error response will be returned.
Make sure this header is always present and contains a valid, up-to-date Partner ID.
Best Practice
To prevent integration issues:
Always validate your
X-Custom-Property-Partner-Idagainst the LIVE/psd2/partnersendpoint.Avoid hardcoding Partner IDs without periodic verification.
Ensure you are sending the header in every request.
Confirm you are using the correct Partner ID for the targeted environment.
Regular validation helps ensure smooth integration and prevents unnecessary request failures.