E-Invoicing — IRN, IRP & GSTR-1 Auto-Population

Learning Objectives

• Know the current turnover threshold for mandatory e-invoicing and how it has evolved
• Understand what IRN, IRP, and the QR code actually are and why each matters
• Generate an IRN end-to-end using NIC or a private IRP
• Read GSTR-1 auto-populated tables (4A/4B/4C, 6A, 9B) and tell what came from e-invoicing
• Know what you can and cannot edit on an IRN-sourced invoice
• Identify the categories exempt from e-invoicing

What Is E-Invoicing — and What It Is NOT

E-invoicing is not a new format of invoice. The supplier still issues their normal tax invoice in their accounting software. The new step: that invoice is registered with a government-authorised portal (the IRP) before being sent to the buyer.

The IRP does three things in one round-trip:

1. Validates the invoice schema
2. Assigns a unique Invoice Reference Number (IRN) — a 64-character hash
3. Returns a signed QR code the supplier must print on the final PDF

Once registered, the invoice flows automatically into:

• The supplier's GSTR-1 (outward supplies)
• The buyer's GSTR-2A / 2B (ITC visibility)
• The e-way bill system (Part A pre-filled)

Common myth: "We use Tally / Zoho / Busy — we already e-invoice." Wrong. Your software issues a normal invoice. Whether it then talks to an IRP and gets an IRN is a separate configuration. Many small businesses think they are compliant and discover at audit that they have raised thousands of "invalid" invoices.

The Turnover Threshold — A Walk Down the Ladder

The government has lowered the threshold in six phases:

Three rules that are easy to get wrong:

1. Aggregate turnover, not entity turnover. It is PAN-level, across all GSTINs. A retail chain with ten GSTINs each doing ₹60 Lakh is not below the limit — combined it is ₹6 Cr.
2. Any preceding financial year from FY 17-18 onwards. If you crossed ₹5 Cr in FY 23-24, you must e-invoice in FY 25-26 even if FY 24-25 was lower. You do not drop below once you cross.
3. B2B only. B2C invoices are excluded — but B2C invoices to a recipient of more than ₹5 Cr turnover still need a dynamic QR code (a different requirement under Notification 14/2020).

What an IRP Actually Is

IRP stands for Invoice Registration Portal. It is a government-authorised endpoint that registers your invoice and returns the IRN.

There are currently six live IRPs:

All IRPs return the same IRN for the same invoice. You cannot get two IRNs for one invoice — the system de-duplicates by hash of the invoice content.

The IRN — what it is

The IRN is a SHA256 hash of three components:

• Supplier GSTIN
• Financial year (in format YY-YY)
• Document number and type

Why the hash matters: the IRN itself is the receipt that your invoice was registered. Buyers can paste the IRN on the GST portal and verify it independently. Counterfeit IRNs cannot exist — the math doesn't allow it.

The QR Code — What Is Encoded

The signed QR code on every e-invoice contains:

• Supplier GSTIN
• Recipient GSTIN
• Invoice number and date
• Invoice value (taxable + tax)
• Number of line items
• Main HSN code
• IRN

It does NOT contain: item-level descriptions, narrations, ledger codes. Those stay in the invoice body.

Any GST officer with a barcode reader (or any phone with a GST verification app) can scan the QR and instantly check: was this invoice registered? Does the value match? Is the recipient GSTIN valid?

This is the practical anti-fake-invoice measure of the entire GST architecture.

End-to-End Flow — Sunrise Retail's First E-Invoice

💼 Sunrise Retail Pvt Ltd

Kiran's projection for FY 2025-26 hits ₹5.4 Crore. By Q3 of FY 24-25 they had already crossed the ₹5 Cr aggregate turnover threshold. From 1 April 2025, every B2B invoice they raise must be e-invoiced.

Step 1 — Sunrise Retail Configures Tally for IRP

Gateway of Tally → F11 → GST Features
  Enable e-Invoicing: Yes
  IRP: NIC (einvoice1.gst.gov.in)
  Authentication: API user credentials from GST portal
    (Services → User Services → Create API User → store username/password)
  Auto-generate IRN on voucher save: Yes

Step 2 — Voucher Entry Triggers IRN Request

On 15 April 2025, Sunrise Retail sells 30 phones to Digital Hub, Secunderabad (Telangana) for ₹4,80,000 + 18% GST.

The moment the sales voucher is saved, Tally pushes a JSON payload to the IRP:

{
  "Version": "1.1",
  "TranDtls": { "TaxSch": "GST", "SupTyp": "B2B" },
  "DocDtls": { "Typ": "INV", "No": "INV-2025-026", "Dt": "15/04/2025" },
  "SellerDtls": {
    "Gstin": "36AACCS1234A1ZP",
    "LglNm": "Sunrise Retail Pvt Ltd",
    "Addr1": "Plot 45, Madhapur Main Road",
    "Loc": "Hyderabad",
    "Pin": 500081,
    "Stcd": "36"
  },
  "BuyerDtls": {
    "Gstin": "36AAJCD9876F1ZL",
    "LglNm": "Digital Hub",
    "Pos": "36",
    "Stcd": "36"
  },
  "ItemList": [
    {
      "SlNo": "1",
      "PrdDesc": "Smartphone 6.7-inch",
      "HsnCd": "8517",
      "Qty": 30,
      "Unit": "NOS",
      "UnitPrice": 16000,
      "TotAmt": 480000,
      "AssAmt": 480000,
      "GstRt": 18,
      "CgstAmt": 43200,
      "SgstAmt": 43200,
      "TotItemVal": 566400
    }
  ],
  "ValDtls": { "AssVal": 480000, "CgstVal": 43200, "SgstVal": 43200, "TotInvVal": 566400 }
}

Step 3 — IRP Responds in ~2 Seconds

{
  "AckNo": 112110234567890,
  "AckDt": "2025-04-15 16:42:08",
  "Irn": "a4b7e9d1c2f6e3d8b5a09c7e4f2d8b6a1c3e5f7d9b2a4c6e8f0d3b5a7c9e1f4d6",
  "SignedQRCode": "eyJhbGciOiJSUzI1NiI6..."
}

Tally embeds the IRN, AckNo, AckDt, and QR code into the printed PDF.

Step 4 — Invoice PDF Is Sent to Digital Hub

The final printed invoice now carries:

• A QR code (top-right or bottom-left)
• The IRN below the invoice number
• The Ack No and Ack Date

Digital Hub's accounts team can scan the QR with their phone and within 5 seconds confirm: invoice valid, GSTIN match, value match — book it.

Step 5 — Auto-Population (Happens Overnight)

By the next day, the same invoice appears in:

• Sunrise Retail's GSTR-1 — Table 4A (B2B Regular)
• Digital Hub's GSTR-2A and GSTR-2B (when the cut-off freezes)
• The e-way bill portal (Part A pre-filled; Sunrise only needs to add vehicle number in Part B)

No one has manually entered the invoice anywhere else. The IRP feed handles it all.

GSTR-1 Tables That Auto-Populate from E-Invoice

Tables that do NOT auto-populate:

• Table 5 (B2C Large, > ₹2.5 Lakh inter-state) — these are NOT e-invoiced
• Table 7 (B2C Small) — these are NOT e-invoiced
• Table 8 (Nil-rated, exempt, non-GST outward) — most are not e-invoiced
• Table 11 (Advances received) — separate process
• Table 12 (HSN summary) — auto-populated from line items but always reviewable

Edit Rules — What You Can and Cannot Change

Once an IRN is generated, the invoice is frozen in the GST ecosystem. You cannot edit the invoice on the GST portal — even though it appears in your GSTR-1.

What you CAN do:

• Cancel the IRN within 24 hours — only if no e-way bill has been generated against it
• After cancellation: issue a fresh invoice with a new number → new IRN

What you CANNOT do:

• Edit the invoice details in GSTR-1 after 24 hours
• Change the recipient GSTIN
• Change the taxable value or tax amount

The only way to fix an IRN-sourced invoice after 24 hours:

• Issue a Credit Note (CRN) to nullify or partially adjust the original
• Or a Debit Note (DBN) to add to the original
• Both must themselves be e-invoiced (they get their own IRN)

This is the most common operational confusion for first-time e-invoice users — they expect the GST portal to behave like Excel.

Categories Exempt from E-Invoicing

Even above ₹5 Cr, the following entities are NOT required to e-invoice:

Important nuance: A bank above ₹5 Cr is exempt from e-invoicing its banking services — but if it sells a repossessed car as goods, that B2B invoice must be e-invoiced.

What Breaks When the IRN Isn't Generated

A surprising number of CFOs treat e-invoicing as a "nice to have." Here is what actually breaks for an invoice that should have been e-invoiced but wasn't:

1. Invoice is invalid in law. Section 31 + Rule 48(5) — without IRN, no document is treated as a tax invoice.
2. Buyer cannot claim ITC. Their GSTR-2B will not show this invoice. They will demand a fresh, e-invoiced bill.
3. Penalty under Section 122 — ₹10,000 per invoice OR 100% of the tax involved (whichever is higher).
4. E-way bill won't generate — Part A pre-fill fails for high-value invoices, blocking shipment.
5. At audit: the entire month's outward turnover for B2B is questioned.

Sunrise Retail — Forward Planning

Sunrise Retail crossed ₹5 Cr aggregate turnover in March 2025 (FY 24-25). From 1 April 2025, every B2B outward invoice must carry an IRN.

Kiran's preparation checklist (executed by Sneha Reddy):

B2C invoices (walk-in retail) continue as normal — no IRP step required. But every sale to Digital Hub, CloudStore, ElectroMart (registered buyers) now goes through IRP.

Practice Exercise

Exercise 1: A jewellery showroom in Hyderabad crossed ₹5 Cr aggregate turnover in FY 22-23 but slipped back to ₹4.2 Cr in FY 23-24 and ₹3.8 Cr in FY 24-25. Must they e-invoice in FY 25-26?

Exercise 2: Sunrise Retail raises an e-invoice for ₹5,66,400 to Digital Hub on 15 April 2025 at 4:42 PM. At 6:30 PM the same day, Sneha realises the quantity should have been 28 phones, not 30. What can she do?

Key Terms

Checklist — what you should now be able to do:

• Determine whether a client must e-invoice based on FY 17-18 onwards aggregate turnover
• Explain the IRN/IRP/QR code flow to a non-technical CFO
• Identify which GSTR-1 tables auto-populate from e-invoice and which are still manual
• Diagnose why a buyer's GSTR-2B is missing an invoice (likely: no IRN generated)
• Choose between IRN cancellation and Credit Note based on the 24-hour window