Send an invoice to one or several clients.

Use this endpoint to send a one time invoice(-s). Provide all data of a BillingTemplate (see Schemas below) and, additionally, an array of one or more BillingTemplateClients in clients. Purchases will be created and invoices sent, one for every Client you have specified.

A BillingTemplate won't be created; if you need to be able to issue repeated, similar invoices, see POST /billing_templates/ and POST /billing_templates/{id}/send_invoice/.

Note that unlike for other requests where you can send BillingTemplate data (like POST /billing_templates/), title and is_subscription are read-only for POST /billing/.