GST e-Invoicing Compliance & Implementation
e-Invoicing applies from ₹5 crore turnover. IRP onboarding, ERP integration guidance, IRN discipline, B2C QR code compliance and penalty defence (₹10,000 per invoice exposure). CA-led implementation for Chennai, Bangalore, Mumbai and pan-India.
Quick answer: E-invoicing under Rule 48(4) of the CGST Rules is mandatory for businesses whose aggregate turnover exceeded ₹5 crore in any financial year since 2017-18, covering B2B supplies, exports and SEZ supplies. An invoice without a valid Invoice Reference Number (IRN) is legally not an invoice — penalties apply and the recipient's credit is at risk.
E-invoicing under Rule 48(4) of the CGST Rules is mandatory for every registered person whose aggregate annual turnover (AATO) exceeded ₹5 crore in any financial year from 2017-18 onwards, for B2B supplies, exports and supplies to SEZ. An invoice issued without a valid Invoice Reference Number (IRN) is, in law, not an invoice at all — with consequences that cascade to your customer's input tax credit.
Virtual Auditor implements e-invoicing correctly the first time: applicability assessment across your PAN, IRP registration, ERP/accounting-software field mapping, exemption analysis, cancellation-window procedures, and defence where invoices were issued without IRNs in the past.
Who Must Generate e-Invoices — and Who Is Exempt
| Item | Position |
|---|---|
| Turnover trigger | AATO > ₹5 crore in any FY since 2017-18 (PAN-level, all GSTINs combined) |
| Documents covered | Tax invoices, credit notes, debit notes — for B2B, exports, SEZ supplies, deemed exports |
| Not covered | B2C invoices (dynamic QR code regime applies instead above ₹500 crore), bills of supply, delivery challans, self-invoices for RCM imports of services |
| Exempt entities (regardless of turnover) | Banks, insurers, NBFCs, GTAs, passenger transport operators, admission-to-cinema suppliers, SEZ units (SEZ developers are covered), government departments and local authorities |
Common trap: AATO is computed at PAN level. A group with three GSTINs of ₹2 crore each is over the ₹5 crore threshold for all of them. Another: crossing ₹5 crore mid-year makes e-invoicing applicable from the start of the next financial year — but companies that crossed the line in an earlier year are already covered and often discover it only during an audit.
How the IRN System Works
- Your accounting/ERP system generates the invoice JSON in the INV-01 schema.
- The JSON is pushed to an Invoice Registration Portal (IRP) — NIC's einvoice1/einvoice2 or a private IRP (Clear, Cygnet, EY, IRIS etc., all free for basic registration).
- The IRP validates, generates the 64-character IRN (a hash of supplier GSTIN + document type + document number + FY), digitally signs the invoice and returns a signed QR code.
- The QR code and IRN must be printed on the invoice issued to the buyer.
- Invoice data auto-populates your GSTR-1 and the buyer's GSTR-2B, and flows to the e-way bill system (Part A auto-filled).
Reporting window and cancellation
- 30-day reporting window: taxpayers with AATO of ₹10 crore and above must report invoices to the IRP within 30 days of the invoice date — the portal hard-rejects older documents. Best practice for everyone is same-day IRN generation.
- 24-hour cancellation: an IRN can be cancelled on the IRP only within 24 hours, and only if no active e-way bill exists. After that, the correction route is a credit note — the invoice cannot be edited.
Penalties for Non-Compliance
| Default | Exposure |
|---|---|
| Issuing an invoice without IRN where e-invoicing applies | Treated as non-issuance of invoice — penalty of ₹10,000 or 100% of the tax due, whichever is higher, per invoice (Section 122(1)) |
| Incorrect / incomplete e-invoice | ₹25,000 per invoice (Section 125 general penalty commonly invoked) |
| Goods moving without valid invoice + e-way bill | Detention under Section 129 — penalty of 200% of tax payable |
| Downstream damage | Buyer's ITC is at risk because a document without IRN is not a valid tax invoice under Rule 48(5) — expect vendor-rating damage and payment holds |
Our Implementation Package
- Applicability memo: PAN-level AATO analysis year-by-year since 2017-18, exemption assessment, and the go-live date that applies to you.
- IRP onboarding: registration on NIC IRP (and a private IRP as fallback), API credentials or offline-tool setup depending on volume.
- Field mapping & master cleanup: HSN codes (6-digit mandatory above ₹5 crore AATO), buyer GSTIN validation, pin-code and state-code corrections — the top rejection causes.
- Process design: same-day IRN SOP, 24-hour cancellation protocol, credit-note correction flow, month-end IRN-versus-sales-register reconciliation.
- Past-default remediation: where invoices were issued without IRN, we quantify exposure, regularise prospectively, and prepare the penalty defence (Section 126 minor-breach arguments, bona fide belief, revenue-neutrality).
e-Invoice vs e-Way Bill — Don't Confuse the Two
The e-invoice validates the document; the e-way bill validates the movement. You may need both (goods worth > ₹50,000 moving inter-state), only the e-invoice (services, or goods delivered without movement), or only the e-way bill (B2C movements). Our SOPs cover the interplay — including auto-generation of e-way bill Part A from the IRN and the Rule 138E blocking risk for return defaulters.
Top IRP Rejection Errors — and the Fixes
| Rejection | Root cause | Fix we implement |
|---|---|---|
| "GSTIN is invalid / cancelled" | Buyer master not validated against the portal | Automated GSTIN status check at order entry, not invoicing |
| "HSN code not valid" | 4-digit HSN where 6-digit is mandatory, or obsolete codes | HSN master rebuild against the current CBIC directory |
| "Duplicate IRN" | Same document number re-pushed after a timeout | Idempotent retry logic; reconcile IRP acknowledgements before re-fire |
| "Pincode does not match state code" | Address masters with mismatched state/pin | One-time address master cleanse + validation rule |
| "Document date beyond permitted window" | Backdated invoices pushed after the 30-day window (₹10cr+ AATO) | Same-day IRN SOP with exception escalation |
Rejection storms usually surface at month-end when invoice volume peaks — exactly when your team has the least time to debug. Master-data hygiene fixes eliminate over 90% of rejections permanently, and the remaining exceptions get a documented escalation path so a stuck IRN never delays a dispatch or a customer's credit.
Sector Notes
Exporters: e-invoices are mandatory for exports and drive the GSTR-1 Table 6A that feeds your IGST refund — IRN errors directly delay refunds. E-commerce sellers: supplies through operators remain B2B or B2C by the buyer's registration; the operator's TCS reporting must reconcile with your IRN data. Job workers: delivery challans for job-work movements need no IRN, but the eventual supply invoice does. Service businesses: no e-way bill interplay, but the 30-day window and SEZ-supply rules still bite.
Frequently Asked Questions
What is the current turnover limit for GST e-invoicing?
₹5 crore aggregate annual turnover, effective 1 August 2023 and continuing to apply. The test is whether your PAN-level AATO exceeded ₹5 crore in any financial year from 2017-18 onwards — not just the latest year. Once applicable, e-invoicing applies permanently even if turnover later falls below the threshold.
What happens if I issue an invoice without an IRN?
Where e-invoicing applies, an invoice without an IRN is not a valid tax invoice under Rule 48(5). Penalty exposure is ₹10,000 or 100% of the tax, whichever is higher, per invoice under Section 122, plus ₹25,000 per invoice for incorrect invoicing. Your buyer's ITC is also jeopardised, and goods in transit can be detained under Section 129 with a 200% penalty.
Can an e-invoice be cancelled or amended after generation?
An IRN can be cancelled on the IRP only within 24 hours of generation, and only if no active e-way bill is attached. It cannot be amended at all on the IRP. After 24 hours, corrections happen through a credit note or debit note (which themselves need IRNs), and the GSTR-1 amendment table. The underlying invoice number can never be reused.
Is e-invoicing required for B2C sales?
No — IRN generation applies only to B2B supplies, exports, SEZ supplies and deemed exports. However, businesses with AATO above ₹500 crore must print a dynamic QR code (enabling UPI payment) on B2C invoices under Notification 14/2020. B2C e-invoicing has been discussed by the GST Council as a future phase but is voluntary/pilot only as of July 2026.
Are SEZ units required to generate e-invoices?
SEZ units are exempt from generating e-invoices for their own supplies. However, SEZ developers are covered, and suppliers to SEZ units must generate e-invoices for those supplies (they are zero-rated B2B supplies). DTA sales by SEZ units also require careful documentation — we map each flow during implementation.
What is the 30-day time limit for reporting e-invoices?
Taxpayers with AATO of ₹10 crore and above cannot report documents older than 30 days to the IRP — the portal rejects them outright. An invoice that misses the window permanently lacks an IRN, triggering the non-issuance penalties. We recommend same-day or T+1 IRN generation SOPs for all clients regardless of turnover.
Does e-invoicing change how I file GSTR-1?
e-Invoice data auto-populates GSTR-1 within a day or two of IRN generation, reducing manual entry. But auto-population is not a substitute for reconciliation: cancelled IRNs, credit notes, B2C invoices and amendments must be verified before filing. Our month-end SOP reconciles the sales register, IRP data and GSTR-1 draft to catch mismatches before they become notices.
We crossed ₹5 crore turnover two years ago but never started e-invoicing. What is our exposure?
Every B2B invoice issued since your applicability date lacks a valid IRN — technically each carries penalty exposure of ₹10,000 or 100% of tax per invoice, and your buyers' ITC is at documentary risk. The practical remediation: start IRN generation immediately, quantify the affected population, and prepare a defence file (bona fide belief, revenue neutrality since tax was fully paid and reported in GSTR-1, Section 126 minor-breach doctrine). Voluntary prospective compliance dramatically improves outcomes if the department raises the issue.
Which software do we need for e-invoicing?
Usually none beyond what you have. Tally, Zoho, Busy, SAP, Oracle and most cloud accounting tools have built-in IRP connectors. Low-volume businesses can use the free NIC offline utility or the e-invoice QR verification app path. The decision is volume-driven: under ~200 invoices a month, the offline/portal route works; above that, API integration pays for itself in avoided rejections and reconciliation time. We configure either route as part of implementation.
Do credit notes and debit notes also need IRNs?
Yes — credit notes and debit notes issued against B2B supplies, exports and SEZ supplies require IRN generation just like the original invoice. This matters operationally because the credit note is your only correction tool once the 24-hour cancellation window closes: a credit note without an IRN is as defective as an invoice without one, and the netting in GSTR-1/2B will not reconcile. Our SOPs put credit-note IRN generation into the same same-day discipline as invoices.