Retrieve all invoices for your organisation, including billing period usage and document references.
file_ref — a reference to the invoice PDF document. Use this endpoint to build an invoice history view in your own billing portal or to programmatically retrieve billing data for accounting systems.
Invoices are generated automatically at the end of each billing period and include your base subscription charge plus any overage calls billed at your tier’s overage rate.
filter=sub_id=3 for all invoices under a specific subscription.sort=created_at:desc for most recent invoices first.