Deployment Pipelines API - Error with itemType DataPipeline via Service Principal only

Hi garddolau ,

Thank you for reaching out to the Microsoft Fabric Community Forum, and we appreciate you bringing this to our attention.

You're correct that during FabCon 2025, Microsoft announced expanded support for Service Principals in Deployment Pipelines, and the current REST API documentation no longer explicitly lists DataPipelines as unsupported.

It appears that deploying DataPipeline artifacts using a Service Principal may still encounter functional limitations or backend constraints, even if not yet documented. The error you're encountering (DeploymentOperationFailed, UnknownError) is consistent with this scenario.

Please follow the recommendations which help you clearing your issue:

• Ensure the Service Principal has the appropriate workspace-level permissions (either "Admin" or "Member") on both the source and target stages.
• Verify that the Service Principal has Fabric Contributor permissions at the tenant level, if required.
• Monitor the Microsoft Fabric Roadmap and Ideas portal for updates on expanded support for APIs and Service Principals.

If the issue persists despite proper permission setup, we recommend raising a formal support ticket so that the backend team can investigate and help you resolve the issue.
You may refer to the following article for guidance on creating a support ticket: How to create a Fabric and Power BI Support ticket - Power BI | Microsoft Learn

Hope this helps. Please reach out for further assistance.
If this post helps, then please consider to give a kudos and Accept as the solution to help the other members find it more quickly.

Thank you.