Platform Docs

How can my app differentiate between owners, managers, and employees?

If your app has the EMPLOYEE_R permission, then you can fetch information about the current user via a GET to /v3/merchants/{mId}/employees/{employeeId}?expand=roles. This will give you information about the role of the current user. If your app has the MERCHANT_R permission, then you can fetch the information about the owner via a GET to /v3/merchants/{mId}?expand=owner.