e-Invoicing in India: Who Needs It, the Threshold, and How IRN Works

e-Invoicing has quietly become one of the most important GST compliance requirements for growing Indian businesses. Despite the name, it is not about emailing a PDF — it is a specific process where every covered B2B invoice is registered with a government portal before it is valid, and comes back stamped with a unique number and a signed QR code.

If your turnover has crossed the threshold, issuing an invoice without going through this process can make that invoice non-compliant — with real penalties attached. This guide explains who is covered, what actually happens when you raise an e-invoice, and how to keep it painless.

Who has to do e-invoicing

e-Invoicing applies based on your aggregate annual turnover (AATO). As of 2026, it is mandatory for businesses whose aggregate turnover has exceeded ₹5 crore in any financial year since 2017-18. Once you cross that line in any year, e-invoicing applies going forward — you do not drop out if a later year is lower.

It applies to B2B supplies — invoices to other GST-registered businesses — as well as exports and supplies to SEZs. It does not apply to pure B2C invoices (sales to unregistered consumers), though those still need a dynamic QR code separately if you are large enough. Certain sectors (such as banks, insurers, and passenger transport) are specifically exempt.

How to know if you have crossed the threshold

Aggregate annual turnover (AATO) is the figure that decides e-invoicing, and it is broader than many businesses assume. It includes all taxable supplies, exempt supplies, exports and inter-state supplies made under the same PAN across all your GSTINs — computed on an all-India basis, not per registration. It excludes GST itself and inward supplies under reverse charge.

The test looks at every financial year from 2017-18 onwards. If your AATO crossed ₹5 crore in any of those years, e-invoicing applies to you — even if your current year is smaller. This trips up businesses that had one strong year and assume a quieter one takes them back out of scope. It does not. Once you are in, you stay in.

What actually happens: the IRN and QR

When you raise an e-invoice, the invoice data is sent to the Invoice Registration Portal (IRP) in a standard JSON format. The IRP validates it, and if everything checks out, returns three things: a unique Invoice Reference Number (IRN), a digitally signed version of the invoice, and a signed QR code.

The IRN is a 64-character hash that uniquely identifies that invoice across the entire GST system — it cannot be duplicated. The signed QR code, which you print on the invoice, lets anyone verify the invoice is genuine and registered. Only after you have the IRN is the invoice considered a valid tax invoice.

• →You prepare the invoice in your accounting software as usual.
• →The invoice JSON is sent to the IRP (directly or through a GST Suvidha Provider).
• →The IRP returns the IRN + signed QR code.
• →The QR and IRN are printed on the invoice you give the customer.
• →The data auto-populates parts of your GSTR-1 — no double entry.

The reporting deadline you might miss

There is a time limit that catches larger businesses out. Taxpayers with AATO of ₹10 crore or more must report an invoice to the IRP within 30 days of the invoice date. Miss that window and the IRP will reject the invoice — you cannot back-date the registration, which can leave you with an invoice you cannot legally use.

For businesses between ₹5 crore and ₹10 crore, this specific 30-day rule has not been applied in the same way, but the safe practice is simple: register e-invoices promptly, ideally at the point of raising them, rather than batching them weeks later.

What e-invoicing is NOT

A lot of confusion comes from the name. e-Invoicing does not mean generating your invoice on the government portal, and it does not mean emailing a PDF to your customer. You continue to raise invoices in your own accounting software exactly as before. e-Invoicing is the extra step of registering that invoice’s data with the Invoice Registration Portal and getting back an IRN and signed QR.

It also does not replace your other returns. The e-invoice data auto-populates parts of GSTR-1, which saves re-keying, but you still file GSTR-1 and GSTR-3B. And it does not apply to every document — it covers tax invoices, credit notes and debit notes for B2B, exports and SEZ supplies, but not, for example, bills of supply issued by composition dealers or pure B2C receipts.

A worked timeline: from invoice to IRN

Walk through a single sale. A Pune manufacturer with ₹8 crore turnover raises a B2B invoice for ₹1,18,000 (₹1,00,000 + 18% GST) to a customer in Gujarat. Because turnover is above ₹5 crore, e-invoicing applies.

The software sends the invoice JSON to the IRP. The IRP validates the GSTINs, the HSN codes and the tax split (here, ₹18,000 IGST because it is inter-state), and returns a 64-character IRN plus a signed QR code. The QR and IRN are printed on the invoice PDF that goes to the customer. That same data flows into the manufacturer’s GSTR-1 for the month, and — because goods are moving inter-state above ₹50,000 — an e-way bill is generated from the same record. One invoice, three compliance outputs, no re-entry.

Cancelling and amending e-invoices

Mistakes happen, and the rules for fixing them are specific. An e-invoice can be cancelled on the IRP within 24 hours of generation — but only fully; you cannot partially cancel one. After 24 hours, you cannot cancel it on the portal at all; instead you issue a credit note or debit note (which is itself e-invoiced) to make the correction.

You also cannot edit an e-invoice once the IRN is generated. Any change means cancelling within the window and re-registering, or issuing a corrective note afterwards. This is another reason accuracy at the point of raising the invoice matters so much under e-invoicing — the window to simply undo is short.

Penalties for getting it wrong

The penalties are structured to make non-compliance expensive. Issuing an invoice that should have been an e-invoice, but was not, can attract a penalty of ₹10,000 per invoice. An incorrect e-invoice can attract ₹25,000 per invoice. And because a non-registered invoice may not be a valid tax invoice, your customer’s input tax credit on it can be challenged — again making your compliance their problem.

Frequently asked questions

Does e-invoicing apply to B2C sales? No — the mandate is for B2B, exports and SEZ supplies. Large businesses do have a separate dynamic-QR requirement for B2C, but that is not the same as IRN-based e-invoicing.

I crossed ₹5 crore this year for the first time — when do I start? e-Invoicing applies from the start of the next financial year after you cross the threshold in any year. Once you are in, you stay in even if a later year is lower.

What happens if the IRP is down when I need to invoice? The system is designed for high availability, and you can register invoices through multiple IRPs and GST Suvidha Providers. For genuine outages, the rules allow a short window to report once service resumes — but the safe practice is to register at the point of raising the invoice.

Is the IRN printed on the invoice, or separate? Both the IRN and the signed QR code must appear on the invoice PDF you give the customer. Software embeds them automatically.

How Deskloc Flow handles e-invoicing

Deskloc Flow generates e-invoices directly from the invoice you raise. It builds the IRP-standard payload, sends it through a GST-authorised route, and brings back the IRN and signed QR — which are embedded on the invoice PDF automatically. e-Way bills can be generated in the same step. You connect your e-invoice portal credentials once, and from then on registration is a click, not a portal-hopping chore.

Because the e-invoice data also feeds your GSTR-1, you are not entering the same invoice twice — raise it once, and it flows through to registration and your return.