E-invoicing has been mandatory for any GST-registered person with aggregate annual turnover (AATO) above ₹5 crore — computed at PAN level, across any financial year from 2017-18 onwards — since 1 August 2023 (CBIC Notification 10/2023-Central Tax). Once a taxpayer crosses ₹5 crore in any year, the mandate stays for good, even if turnover later falls. This is settled compliance, not a new FY 2026-27 change — verify the client crossed the threshold in the correct year and hasn't simply assumed it doesn't apply because current-year turnover dipped.
Since 1 April 2025, taxpayers with AATO of ₹10 crore or more must report an invoice to the Invoice Registration Portal (IRP) within 30 days of the invoice date. Invoices reported after the window are rejected outright by the IRP — they never get an Invoice Reference Number (IRN) — regardless of what the seller's own books show. Sample invoices near month-ends and around any billing-system downtime, where late uploads are most likely.
A supply invoice without a valid IRN is not a valid tax invoice under Rule 48(5) — the document does not legally exist for GST purposes even though goods/services moved and cash may have changed hands. The seller is exposed to a penalty of ₹10,000 per invoice or 100% of the tax involved, whichever is higher (Sec 122). The bigger audit risk usually sits with the BUYER: input tax credit claimed against an invoice with no valid IRN is credit claimed on an invalid document and is a live disallowance risk on inspection.
The seller's own sales register will show every invoice regardless of IRN status — it proves nothing about compliance on its own. Pull the e-invoice/IRN log from the GST portal or the client's e-invoicing solution and reconcile IRN-bearing invoices against GSTR-1 outward supplies and, from the buyer side, against GSTR-2B auto-populated credit. A gap between "invoice raised" and "IRN generated" is exactly what clause reporting and ITC risk assessment need to quantify.
A valid IRN auto-populates the e-way bill (where applicable) and GSTR-1 — so a pattern of missing IRNs often shows up first as e-way bill or GSTR-1 mismatches rather than as an isolated e-invoicing failure. Treat e-invoicing testing as part of the outward-supply reconciliation, not a standalone checkbox.
Threshold history, for context: e-invoicing phased in from ₹500 Cr (Oct 2020) down through ₹100 Cr, ₹50 Cr, ₹20 Cr, ₹10 Cr, to the current ₹5 Cr (1 Aug 2023). The 30-day IRP upload rule for ₹10 Cr+ AATO is the newer, actually current compliance point (1 Apr 2025) — don't conflate the two.
The GSTR-9C reconciliation template carries the outward-supply reconciliation this feeds; the IMS guide covers the buyer-side credit-acceptance workflow where a missing IRN shows up as risk.
CORAA reconciles outward supplies against GSTR-1/2B automatically — see the AI Modules or start free: your first audit is on us. See also the FY 2026-27 GST compliance checklist for the other start-of-year items.
No — it has applied since 1 August 2023 (CBIC Notification 10/2023-Central Tax), reduced in stages from an original ₹500 crore threshold in October 2020. Any GST-registered person whose aggregate turnover crossed ₹5 crore in ANY financial year since 2017-18 must e-invoice, and the requirement is permanent once triggered — it does not lapse if turnover later falls below ₹5 crore. Auditors should verify the client correctly identified the year it crossed the threshold, not assume current-year turnover is the only test.
Effective 1 April 2025, taxpayers with AATO of ₹10 crore or more must upload an invoice to the Invoice Registration Portal within 30 days of the invoice date. The IRP rejects invoices reported after that window — no IRN is issued, and the document is not a valid tax invoice under Rule 48(5), regardless of what the seller's internal books show.
Both, but differently. The seller faces a penalty of ₹10,000 per invoice or 100% of the tax involved, whichever is higher (Sec 122). The buyer's risk is often larger in practice: input tax credit claimed against an invoice without a valid IRN is credit claimed on an invalid document, which is a straightforward disallowance on inspection — auditing accounts payable on a ₹5 Cr+ or ₹10 Cr+ counterparty should always include an IRN-presence check, not just a GSTR-2B match.
Pull the actual IRN log (from the GST portal or the client's e-invoicing solution) rather than relying on the sales register, which shows every invoice regardless of IRN status. Reconcile IRN-bearing invoices to GSTR-1 outward supplies, sample invoices near month-end and system-downtime periods for the 30-day window (if AATO ≥ ₹10 Cr), and on the purchase side, cross-check high-value vendor invoices against GSTR-2B and the vendor's own IRN status before accepting the related ITC.
