API v2026-10-16

One invoice contract. Explicit routing decisions.

Send a canonical invoice, preserve an idempotency key, and receive a versioned ruleset outcome with a request correlation ID.

Submit an invoice

POST /api/v1/invoices
Authorization: Bearer vtr_live_...
Idempotency-Key: 29f3e57e-...
Content-Type: application/json

{
  "schema_version":"2026-10-16",
  "external_id":"ERP-AP-88421",
  "document_type":"invoice",
  "currency":"EUR",
  "routing":{"destination_country":"FR","archive_policy":"eu-10y"}
}

Safe integration behaviour

Use the same idempotency key only for an identical logical write.
Treat RULESET_NOT_AVAILABLE as a hard stop, not a warning.
Provision access only from verified billing webhook state.
Verify timestamped webhook signatures and acknowledge events idempotently.