Reference data - the shipping service types available to your company (e.g. Standard, Express, Same-day), for use in pkg.serviceType (or pkg.serviceTypeId if your company has custom per-company service types) when creating a shipment. id is null for the fixed built-in types.Note: this endpoint is part of the general shipping request API, not the API-key integration surface. Authenticate with a company-id header instead of X-API-Key.