Upload a custom-rendered PDF for an invoice that is currently in the Finalizing state. This endpoint is used by external PDF rendering engines that receive the invoice.pdf.generation_requested webhook.
Enterprise Feature: This endpoint requires the Custom PDF Rendering feature to be enabled.
After upload, Fynn will:
invoice:writeBearer authentication header of the form Bearer <token>, where <token> is your auth token.
Invoice identifier
The PDF file to upload