E-invoice QR code explained

Where the QR code comes from

When a business covered by e-invoicing reports an invoice to the Invoice Registration Portal (IRP), the IRP returns the IRN and a signed QR code. The supplier's software prints this QR on the invoice. The supplier does not create the QR itself; if the code on an invoice was made by the billing software without going through the IRP, it is not an e-invoice QR. The full process is in e-invoicing and IRN.

What the QR contains

The data is signed with the IRP's digital key. Changing even one character, such as the value, breaks the signature, which is what makes the QR useful for checking. The main item's HSN is the line with the highest taxable value.

How a buyer can verify it

1. Install the QR verification app published for GST e-invoices, or use the verify option on the e-invoice portal.
2. Scan the QR on the printed or PDF invoice.
3. The app checks the signature and shows the decoded details.
4. Compare them with the invoice: GSTINs, number, date, value.
5. If the signature fails or details differ, ask the supplier for the correct registered invoice before booking credit.

This check is quick at the goods-inward desk and helps catch altered or fake invoices. It does not prove the supplier has paid tax; the invoice reaching your GSTR-2B is still the test for credit.

E-invoice QR vs payment QR

Two different QR codes can appear on Indian invoices, and people mix them up:

Many small businesses also print a simple UPI QR on invoices so customers can pay. That is useful but has nothing to do with e-invoicing; see UPI QR code on invoices.

Using the QR at the goods-inward desk

For a buyer receiving many supplier invoices, a short routine at the inward desk catches problems before they reach the accounts team:

1. When goods arrive, scan the QR on the supplier's invoice with the verification app.
2. Check that the recipient GSTIN in the QR is yours, and for the right branch.
3. Check that the invoice value matches the printed total and the purchase order.
4. If the supplier is above the e-invoice limit and the invoice has no QR or IRN, hold the bill and ask for the registered version.
5. Note the IRN in your purchase entry so the bill can be traced when matching GSTR-2B.

This takes under a minute per bill, and it is far easier than chasing a supplier months later when credit is questioned.

Printing it properly

• Print the QR large enough to scan: a common minimum is around 2.5 cm square on A4.
• Keep a white margin around it; do not print over a logo or watermark.
• Print the IRN in text as well, so it can be typed if the QR is damaged.
• On thermal or dot-matrix printers, test that phones can read it before going live.
• In PDF invoices, embed the QR as an image at good resolution, not a blurred screenshot.

Common mistakes

• Printing a QR generated by the billing software instead of the IRP's signed QR.
• Sending the invoice before the IRN is received, then sending a second copy with the QR, so the buyer has two versions.
• Using the e-invoice QR as a payment QR, or vice versa.
• Re-issuing a corrected invoice with the old QR after editing values in the PDF. The signature will fail.

This is general information, not tax advice.

Where Cashflow OS fits

On plans that include e-invoicing, Cashflow OS can get the IRN and signed QR from the IRP for a synced Tally sales voucher, using your own e-invoice API login, and write them back into Tally so the Tally print carries the QR. An IRN already made in Tally is shown, not made again. Cashflow OS documents such as quotations and proforma invoices can carry your UPI details for payment, which is a separate thing from the e-invoice QR. Invoices synced from Tally appear in the GSTR-1 view with bill-wise detail.