Billing API

Create Voyant invoices and retrieve provider-issued documents.

Endpoints

Method	Path	Description
POST	/v1/billing/invoices	Create a draft invoice with line items.
GET	/v1/billing/invoices/:invoiceId	Fetch invoice header + lines.
POST	/v1/billing/invoices/:invoiceId/send	(Reserved) Trigger invoice delivery workflow.
GET	/v1/billing/invoices/provider	Stream the provider-issued invoice PDF (SmartBill).

Workspace-scoped API keys are required. Use billing:write to create or send invoices and billing:read to fetch invoices or provider PDFs. Provider exports rely on encrypted credentials (Google Cloud KMS).

Key concepts

• The create endpoint writes to the Voyant billing tables (billing.invoices + billing.invoice_lines) and returns the new invoice ID.
• Fetching provider PDFs uses configured accounting integrations (currently SmartBill). Ensure KMS env vars are set (GCP_SERVICE_ACCOUNT_KEY + GCP_KMS_INTEGRATIONS_KEY_NAME, or fallback KMS in controlled environments).
• Sending invoices is not yet implemented; the endpoint currently returns 501 Not Implemented to preserve the contract for future workflows.
• All date parameters accept ISO strings; the API stores issueDate/dueDate as timestamp values when provided.