Also known as: E-invoice · Invoice Reference Number
Unique 64-character hash generated by the Invoice Registration Portal (IRP) for an applicable document issued by a business covered by the e-invoicing mandate.
IRN stands for Invoice Reference Number — a unique 64-character hash that the Invoice Registration Portal (IRP) generates for applicable documents issued by businesses covered by the e-invoicing mandate. The aggregate-turnover threshold has been progressively lowered and is ₹5 crore for the current mandate described here. Because notifications can change, confirm applicability for the relevant financial year and taxpayer on the official e-invoice portal.
In an API-assisted e-invoicing workflow, accounting software prepares invoice JSON in the prescribed schema and sends it through an authorised connection to the IRP. The IRP validates the submission and, when accepted, returns the IRN and signed QR-code data for the invoice document. Response time and acceptance depend on the provider, network, portal, and payload. An applicable document is not a valid e-invoice until the IRP has registered it.
Cancellation of an e-invoice is permitted only within 24 hours of generation. After that, the only correction route is a credit note. Amendments (other than cancellation) cannot be made via the IRP — they have to flow through the GSTR-1 amendment table.
In ReadyBooks.ai, an eligible user explicitly chooses Generate IRN. ReadyBooks sends the supported payload through the configured e-invoice provider; a successful response records the IRN and signed QR-code data for the invoice. Saving an invoice alone does not generate an IRN, and provider or portal acceptance remains authoritative.