UUID of the company on whose behalf the request is made. Required for every Pay endpoint.
See The company-id header for details on how to obtain
a value for this header and the error responses to expect when it is missing or invalid.

If the deprecated company_id query parameter is also sent as a single-company selector, both
values must match; the API returns 422 Unprocessable Entity when they disagree. Endpoints whose
company_id accepts several companies document their own rules.