GST

E-Invoice (IRN)

A GST invoice reported to the government portal and stamped with an Invoice Reference Number (IRN) and QR code.

E-invoicing requires certain businesses to report B2B invoices to the Invoice Registration Portal (IRP) before or at the time of issue. The portal validates the invoice and returns a unique Invoice Reference Number (IRN) and a signed QR code, which must appear on the invoice.

E-invoicing applies above a notified turnover threshold. It standardises invoice data across the GST system and feeds GSTR-1 and e-way bills, reducing reconciliation effort.

Under the bonnet the flow is machine-to-machine: the seller's system generates the invoice, converts it to the notified JSON schema, and transmits it to the Invoice Registration Portal. The IRN it receives back is a hash computed from the supplier's GSTIN, the financial year, the document type and the document number — which is why the same invoice can never be registered twice, and why the numbering series must never repeat within a year.

Coverage is wider than the word invoice suggests: B2B invoices, export invoices, and the credit and debit notes attached to them all need IRNs once a business is within the mandate, while B2C bills stay outside it. The QR code the portal returns is signed, which is what makes the printed invoice verifiable offline — anyone can scan it and confirm the document was really registered, and that its key details match what the seller reported.

The operational traps are mundane. An invoice issued without an IRN by a mandated business is not a valid tax invoice, which puts the buyer's credit at risk — large buyers increasingly refuse such documents outright. Editing an already-registered invoice in the books breaks the tie between the ledger and the IRP record. And because IRN data flows automatically into GSTR-1, a document cancelled on the portal but left alive in the books produces a mismatch that surfaces at filing.

Common questions

Is e-invoicing required for B2C sales?

No. The mandate covers B2B supplies, exports and their credit and debit notes for businesses above the notified turnover; supplies to unregistered consumers are outside it. Separate dynamic QR-code requirements exist for B2C invoices of very large taxpayers, but that is a different obligation and no IRN is generated for consumer bills.

Can an e-invoice be amended after the IRN is generated?

Not on the portal — the IRP permits only full cancellation, and only within a short window after generation. Once that passes, the registered document stands, and any change in value or tax must be effected through a credit or debit note carrying its own IRN. The books and the return then reflect the pair together.

What happens if a covered business issues an invoice without an IRN?

The document is not a valid tax invoice in law, exposing the seller to penalty and leaving the buyer's input tax credit on shaky ground. In practice the fix is to register the invoice belatedly where the portal permits, or cancel and reissue; prevention — blocking dispatch until an IRN exists — is the control that actually works.

Does the e-invoice replace the need to file GSTR-1?

No. IRN details auto-populate the corresponding GSTR-1 tables, which removes re-keying, but the return must still be reviewed and filed — and auto-populated rows can be edited, so the filed return remains the taxpayer's own declaration. Documents outside the mandate, such as B2C supplies, still have to be added to GSTR-1 manually.

Related terms

E-Way Bill GSTR-1 GSTIN

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