GSTN Verified E-Invoice App with QR Code

GSTN Verified E-Invoice App with QR Code

The GSTN e-invoice verifier app lets anyone — buyer, auditor, or banker — scan the QR code on a supplier's invoice and confirm within seconds whether it is IRP-registered and untampered. For FY 2026-27, every registered taxpayer (outside the notified exempt categories) with aggregate turnover above ₹5 crore in any financial year from 2017-18 onwards must generate an IRN for every B2B supply, export, and credit/debit note. Skipping this step doesn't just attract penalty — it invalidates the buyer's ITC.

What an E-Invoice Actually Is — and What It Is Not

An e-invoice is not a government-generated bill. Your accounting software or ERP still produces the invoice. What changes is the registration step: the invoice data is sent in a standardised JSON schema to an Invoice Registration Portal (IRP), which validates the data, assigns a unique 32-character Invoice Reference Number (IRN), attaches a digitally signed QR code, and returns the enriched JSON to you. You then incorporate the IRN and QR code onto the invoice you hand to the buyer.

The IRP does not store the invoice — it stores a hash. The signed QR code is the cryptographic proof that the invoice was registered. That is why offline verification through the GSTN app works: it validates the digital signature without needing a live server call.

Key terms to keep straight:

• IRN — 64-character SHA-256 hash (displayed as a 32-hex-character string on most portals) of GSTIN + document number + FY + document type.
• IRP — Invoice Registration Portal. NIC operates the primary portals at einvoice1.gst.gov.in and einvoice2.gst.gov.in. Private IRPs (Cygnet, Clear, IRIS) are also GSTN-approved.
• e-Invoice schema — the standardised JSON published by GSTN (currently schema version 1.1) that your ERP must produce before calling the IRP API.

Who Must Issue E-Invoices in FY 2026-27

The ₹5 Crore Threshold

Under Notification No. 10/2023-Central Tax dated 10 May 2023 (effective 1 August 2023), e-invoicing applies to any registered person whose aggregate annual turnover exceeds ₹5 crore in any financial year from 2017-18 onwards. Once crossed, the obligation is permanent — there is no exit if turnover falls back below the threshold in a subsequent year.

"Aggregate turnover" carries the same meaning as under Section 2(6) of the CGST Act — it includes taxable, exempt, zero-rated, and non-GST supplies across all GSTINs under a single PAN, but excludes inward supplies and GST itself.

Practical check for FY 2026-27:

• Pull your GSTR-9 or GSTR-9C for FY 2024-25. If aggregate turnover exceeded ₹5 crore, e-invoicing applies for the whole of FY 2026-27 from 1 April 2026.
• If you crossed ₹5 crore mid-year in FY 2025-26 but had not crossed it before, e-invoicing becomes mandatory from 1 April 2026.
• If you only crossed it in FY 2026-27 itself, the obligation kicks in from the beginning of that year per the "any preceding FY" language — but in practice the GSTN portal enables e-invoicing prospectively, so seek a clarification from your jurisdictional GST officer if this edge applies to you.

Supplies Covered and Supplies Excluded

Must generate IRN:

• B2B tax invoices (inter-state and intra-state)
• Exports (with or without payment of IGST)
• SEZ supplies — by the supplier to the SEZ unit, not by the SEZ unit itself (SEZ units are exempt from the outward e-invoice mandate)
• Credit notes and debit notes linked to covered invoices
• Reverse-charge invoices (where the recipient is the supplier for tax purposes)

Exempt from IRN:

• B2C supplies (but see the separate dynamic QR code requirement for taxpayers above ₹500 crore)
• SEZ units and SEZ developers on outward supplies
• Government departments and local authorities (Section 9(3) notified entities)
• Banking companies, insurance companies, financial institutions, and NBFCs for their core financial supplies
• Goods Transport Agencies (GTA) for freight services
• Passenger transportation services
• Multiplex cinema services for B2C tickets
• Free Trade Warehousing Zones

Inside the QR Code: What the Digital Signature Encodes

The signed QR code generated by the IRP encodes the following mandatory fields from the invoice schema:

1. Supplier GSTIN
2. Recipient GSTIN
3. Invoice number and invoice date
4. Document type (INV / CRN / DBN)
5. Total taxable value
6. Total invoice value (including GST)
7. Total GST amount (IGST / CGST+SGST breakdown)
8. Number of line items
9. HSN code of the primary line item (highest value item)
10. IRN (the 32-character hash)
11. IRP signing timestamp (IST)

The IRP signs this payload using its private key. The GSTN app holds the corresponding public key. When you scan the QR, the app re-computes the hash and verifies the signature — if a single digit has changed on the printed invoice, the verification fails.

This is why the QR code is more reliable than the printed IRN alone: the IRN can be copied and pasted onto a fake invoice, but a tampered QR code will always fail cryptographic verification.

Step-by-Step: How to Use the GSTN E-Invoice Verifier App

On Mobile (Android and iOS)

1. Search "e-Invoice QR Code Verifier" on Google Play Store or Apple App Store. Install the app published by NIC (National Informatics Centre).
2. Open the app. No login or registration is needed for basic QR verification.
3. Tap Scan QR Code and point the camera at the QR code on the supplier's invoice. Hold steady for 2–3 seconds.
4. The app displays the decoded invoice header: supplier GSTIN, buyer GSTIN, invoice number, date, taxable value, total GST, IRN, and IRP timestamp.
5. Cross-check three things against the printed invoice: (a) supplier GSTIN matches the letterhead, (b) invoice number matches exactly, (c) taxable value and GST amounts match the invoice footer.
6. If the app returns a "Signature Invalid" or "QR Decode Error" result, do not book the invoice. Contact the supplier immediately and ask for a fresh IRN.

On the Web Verifier

Navigate to einvoice1.gst.gov.in → Help → Verify Signed Invoice. Upload the signed JSON returned by the IRP (if your supplier shares it) or manually enter the IRN to retrieve the registered details. This is more useful for auditors reviewing bulk invoices without a phone camera.

What a Verification Result Tells You

The 30-Day Time Limit for IRN Generation

For taxpayers with aggregate turnover above ₹100 crore, the IRP portal enforces a 30-day window from the invoice date. Submit an invoice to the IRP more than 30 days after the invoice date and the portal rejects it outright — you cannot get an IRN. The only remedy is to cancel that invoice in your books and raise a fresh one dated within the current 30-day window.

For taxpayers below ₹100 crore (but above ₹5 crore), the 30-day limit has been announced in advisories but is not yet enforced at the portal level as of the time of writing. However, there is an operational reason to generate the IRN within 24 hours regardless: the buyer's GSTR-2B auto-populates from IRP data on an almost real-time basis, and a delayed IRN means delayed GSTR-2B reflection, which delays the buyer's ITC claim.

What happens when the 30-day window lapses (>₹100 crore taxpayers):

1. The IRP rejects the JSON with error code 2150 (document date is beyond the allowed period).
2. The original invoice must be cancelled in your system (even though it never got an IRN).
3. You raise a new invoice with a current date, get the IRN, and send the corrected invoice to the buyer.
4. The buyer must reverse any tentative ITC already booked on the original invoice and rebook on the corrected invoice in the correct GSTR-3B period.

ITC at Stake: What Every Buyer Must Verify

Under Rule 48(5) of the CGST Rules, an invoice issued by a covered supplier without an IRN is not a valid tax invoice. Section 16(2)(aa) (inserted by Finance Act 2021) links ITC eligibility to the invoice appearing in GSTR-2B — and GSTR-2B pulls its data from the IRP. No IRN = no IRP registration = no GSTR-2B entry = ITC disallowed.

This means the QR code scan is not a nice-to-have — it is your first line of defence before locking GSTR-3B.

Buyer's three-step ITC protection checklist:

1. Scan and verify the QR code using the GSTN app on receipt of every B2B invoice from a supplier you know (or suspect) is above the ₹5 crore threshold.
2. Match the invoice with GSTR-2B before filing GSTR-3B. Invoices not appearing in GSTR-2B should not be claimed under Section 16(2)(aa), even if the IRN exists, until the mismatch is resolved.
3. Raise a supplier query using the GST portal's ITC mismatch communication pathway if an IRN-registered invoice is missing from your GSTR-2B — this sometimes happens due to a mismatch in your GSTIN as reported by the supplier at the IRP.

Worked Example: Real Numbers on a Missed IRN

Scenario: Apex Auto Components Pvt Ltd (Pune, GSTIN: 27AAAAA1234A1Z5) had aggregate turnover of ₹9 crore in FY 2024-25. E-invoicing is mandatory for FY 2026-27. During April and May 2026, their legacy billing software was not integrated with the IRP, and they issued 35 B2B invoices without IRN.

Average invoice value: ₹3,00,000 taxable value × 18% GST = ₹54,000 GST per invoice.

Penalty exposure for Apex Auto (Supplier): Under Section 122(1)(b) of the CGST Act, issuing an invoice not in accordance with the prescribed provisions attracts a penalty of ₹10,000 per contravention or the tax amount involved, whichever is higher.

Since ₹54,000 > ₹10,000, the penalty is ₹54,000 per invoice.

Total supplier penalty: 35 × ₹54,000 = ₹18,90,000

ITC loss for buyers: Assume 10 different buyers each received between 2–5 of these invoices. None of those invoices appear in GSTR-2B. The aggregate ITC blocked across all 10 buyers: 35 × ₹54,000 = ₹18,90,000

If buyers had claimed this ITC in GSTR-3B and the department issues an ASMT-10 notice after matching GSTR-2B vs GSTR-3B, each buyer faces a demand plus 18% interest per annum from the date of incorrect ITC claim.

What Apex Auto should have done:

• Integrated their ERP with NIC's GSTN Sandbox in January 2026 (pre-go-live testing period).
• Used the NIC bulk upload offline tool as a bridge until API integration was live.
• Generated IRNs within 24 hours of invoice creation; shared the QR-embedded PDF with buyers on the same day.

Correction path: Since these invoices are less than 30 days old (April–May 2026), Apex Auto can still generate IRNs on the existing invoice dates if their turnover is below ₹100 crore. If above ₹100 crore, they must cancel the invoices, re-issue with current dates, and inform each buyer to update their records.

Common E-Invoice Errors That the IRP Rejects — and How to Fix Them

These are the errors that account for the majority of IRP rejections in practice. If your ERP is not parsing IRP error codes, you are fixing these manually every time.

Errors on the Supplier Side

• Wrong recipient GSTIN (error `2002`): Verify the buyer's GSTIN on the GST portal search before uploading. A single transposed digit returns this error.
• Mismatched place of supply (`2271`): For inter-state B2B, the place of supply must be the state where the recipient is registered (Section 12/13 of IGST Act). Confirm this is correctly coded in your ERP's billing template.
• Invalid HSN code (`2271` / `2240`): With e-invoicing, every line item needs a valid 4-digit (or 6-digit for above ₹5 crore turnover) HSN code per the customs tariff. A mismatch against the published HSN master returns an error. Keep a validated HSN master in your ERP and sync it after every customs tariff amendment.
• Missing UQC — Unit Quantity Code (`2240`): GSTN mandates a valid UQC code (e.g., NOS, KGS, LTR, MTR) from its published list for every line item. Generic descriptions like "units" or "nos" in lowercase without a matching UQC code will fail.
• Missing or invalid PIN code in recipient address (`2002`): The recipient's address in the JSON must contain a valid 6-digit Indian PIN code for domestic B2B. This is often skipped if your CRM stores only city and state.
• Editing invoice post-IRN (`1005`): Once an IRN is generated, the underlying invoice is locked. If you discover an error — wrong amount, wrong GSTIN — you must cancel the IRN within 24 hours of generation (the only window for IRP-level cancellation) and generate a fresh IRN on a corrected invoice. After 24 hours, the IRP will not accept a cancellation request, and you will need to issue a credit note to reverse the incorrect invoice.

Errors on the Buyer Side

• Booking ITC without scanning the QR code: The printed IRN on an invoice can be forged. The QR code cannot — verify it.
• Not monitoring GSTR-2B discrepancies: GSTR-2B is generated on the 14th of each month. If a supplier's invoice is missing, it could mean the IRN was generated after the GSTR-2B cut-off. Do not claim ITC in GSTR-3B for invoices absent from GSTR-2B without following up with the supplier first.
• Claiming ITC on cancelled IRNs: Suppliers sometimes cancel an IRN and re-issue with a fresh IRN. If you received the original invoice and scanned it, the QR code may now be for a cancelled IRN. The web verifier on einvoice1.gst.gov.in shows cancellation status — use it for high-value invoices.

B2C Dynamic QR Code: A Separate but Related Requirement

If your aggregate turnover exceeds ₹500 crore, a separate obligation applies to B2C invoices (i.e., supplies to unregistered persons): you must display a dynamic QR code on each B2C invoice. This QR code encodes the payment details and links to a UPI payment flow. This is governed by Notification No. 14/2020-Central Tax.

This is distinct from the e-invoice (IRN) QR code and is not verified using the GSTN e-invoice verifier app. It is mentioned here only because the two are commonly confused — do not conflate them when setting up your billing system.

Key Takeaways

• ₹5 crore aggregate turnover in any FY from 2017-18 triggers mandatory e-invoicing — check your GSTR-9 for FY 2024-25 to confirm your FY 2026-27 obligation.
• The GSTN e-invoice verifier app (NIC, on Google Play and iOS) verifies the IRP's digital signature on the QR code — a passing result is reliable proof of a genuine IRN; a failing result is grounds to reject the invoice and withhold ITC.
• Rule 48(5) + Section 16(2)(aa) together mean that a covered supplier's invoice without a valid IRN is not a lawful tax invoice and cannot support an ITC claim.
• Suppliers with turnover above ₹100 crore face a hard 30-day window at the IRP portal — submit late and the invoice is rejected; the original must be cancelled and a new invoice issued.
• The most common IRP rejection causes are wrong recipient GSTIN, invalid HSN, missing UQC, and mismatched place of supply — fix these at the ERP master-data level, not invoice by invoice.
• Post-IRN editing is not possible — cancel within 24 hours of IRN generation if an error is found; after 24 hours, issue a credit note.
• For the worked example above, a 35-invoice non-compliance carried ₹18.9 lakh in supplier penalty exposure and an equal amount of buyer ITC at risk — numbers that make IRP integration a financial necessity, not a compliance checkbox.