GST E-Invoice Guide for Retailers: Thresholds and IRN Basics

E-invoicing is India's system for reporting B2B invoices to the Invoice Registration Portal (IRP). The IRP checks the invoice, returns an Invoice Reference Number (IRN) and gives you a signed QR code to print. Whether you need it depends mainly on your turnover. The rules below are as of October 2026. The deadlines have changed several times, so check the GST e-invoice portal and your CA before you act.

Who must issue e-invoices

Your obligation depends on your aggregate annual turnover (AATO). The test adds up turnover across all GSTINs under the same PAN. As of October 2026, the threshold for B2B e-invoicing is ₹5 crore AATO. Shops below that level do not generate IRNs for their B2B invoices. Shops above it must generate an IRN for each eligible B2B invoice.

Two points matter for retailers:

• A growing shop can cross the threshold within a year. Plan the billing setup before the deadline, not after it.
• Being below the threshold does not remove GST duties. You still need correct tax invoices, correct tax rates and proper records.

B2B and B2C at the counter

B2B means a sale to a buyer with a GSTIN. A pharmacy supplying a nursing home, or a shop selling to a registered reseller, makes a B2B sale. Capture the buyer's GSTIN at billing, because the IRN needs it.

B2C means a sale to an unregistered customer, which covers most walk-in sales. The dynamic QR code rule for B2C invoices came from Notification 14/2020-Central Tax. It first applied to taxpayers with turnover above ₹500 crore. Ask your CA whether any QR rule applies to your shop today.

What the IRN and signed QR code mean

• IRN: A unique invoice reference issued by the IRP. Store it with the invoice. Buyers and auditors use it to check the invoice.
• Signed QR code: Printed on the e-invoice. It carries the signed invoice data.
• Cancellation: An IRN can be cancelled on the portal within 24 hours of generation, with a reason. After that, issue a credit note under the rules.
• Reporting window: Recent rules set a deadline for reporting invoices to the IRP. Press coverage describes it as 30 days from the invoice date. Confirm the window for your turnover band on the portal, and do not assume a longer one.

What a shop needs in practice

Most small shops do not connect to the IRP directly. They use a GST suvidha provider (GSP) or another IRP-approved route. Your billing system must send the invoice data and receive back the IRN and QR code. Check these points with your vendor:

• A valid GST registration and a clear reporting route for each invoice.
• Product HSN codes set correctly, with the right GST rate for each item.
• The buyer's GSTIN captured at billing for B2B sales, with a check that it is valid.
• An invoice number series that never repeats.
• Credit notes and cancellations that follow the same rules.
• Records kept for the period the law requires. GST records are normally kept for six years (72 months).

A checklist before the deadline

1. Ask your CA to confirm your AATO for the last financial year and the current year.
2. Confirm whether your B2B invoices must carry an IRN.
3. Check that every product has an HSN code and the right GST rate.
4. Make a test B2B invoice for a registered buyer and check the fields against your CA's list.
5. Ask the vendor how the system behaves when the internet is down, then test it.
6. Set a go-live date and train cashiers to capture buyer GSTINs.

Common mistakes to avoid

• Treating the threshold as a one-time check. Your turnover changes. Review your status every financial year.
• Leaving buyer GSTINs blank on B2B sales. Cashiers skip the field when the counter is busy. Make it a required step for registered buyers.
• Using one generic HSN code for everything. A wrong code can lead to rejected invoices and the wrong tax.
• Editing a sent invoice. Correct it through the cancellation or credit note route under the rules, never by changing the number or the amount.
• Confusing the receipt QR code with the e-invoice QR code. They are different. The e-invoice QR comes from the IRP-registered invoice.

Returns and credit notes

A sales return on a B2B invoice needs a credit note under GST rules, not a changed bill. Your billing system should link the credit note to the original invoice, record the reason and keep the original IRN on file. Ask your CA how credit notes are reported, and test one in the trial before go-live.

Offline billing and IRN generation

Generating an IRN needs the IRP online. Billing can continue at the counter during an outage, but the IRN step needs a connection. Ask the vendor how offline invoices are queued, how long they can wait and what happens if the IRP rejects one. Do not accept a vague answer.

Where AIFFICIENTO fits

AIFFICIENTO is a retail POS with a local server. Sales stay on your PC when the internet is down, and they sync when the connection returns. Tax authority e-invoicing integrations are configured per shop on request. For India, that covers GST e-invoicing. Use the Request integration button in Settings, Store. Our team configures and tests it for your GST registration. We do not claim certification, approval or accreditation from any tax authority.

The receipt designer prints your GSTIN, tax lines and a QR code. The receipt QR code is a receipt feature. It is not an IRN. Your e-invoice QR comes from the integration once it is set up and tested.

The Business plan includes tax-integration setup and dedicated onboarding for each branch. Starter is ₹499 per month for one counter and up to three users. Growth is ₹1,299 per month. Read the full details on pricing. For the India product page, see POS software for India. For the feature overview, see tax and e-invoicing.

Start a 30-day free trial with full access and no credit card. Use it to test your billing flow, including a B2B invoice with a buyer GSTIN, before any deadline arrives. Starter is ₹499 per month after the trial.