Most GST compliance failures are expensive but repairable. You pay the tax, you pay the interest, and the matter closes.
e-Invoicing has a failure mode that is not repairable, and it comes from one short provision. Rule 48(5) says that where e-invoicing applies, an invoice issued in any other manner shall not be treated as an invoice at all.
Not a defective invoice. Not an invoice attracting a penalty. Not an invoice.
Who it applies to
e-Invoicing applies where aggregate annual turnover exceeds ₹5 crore, following Notification 10/2023-Central Tax with effect from 1 August 2023.
Three parts of that test cause the most trouble.
Aggregate turnover is PAN-level, not GSTIN-level. It is computed across every registration under the same PAN, all states together, and it includes taxable supplies, exempt supplies, exports and inter-state supplies to distinct persons. A group with four state registrations of ₹1.5 crore each has aggregate turnover of ₹6 crore and every one of those registrations is covered, even though not one of them individually approaches the threshold.
It looks back at any preceding financial year from 2017-18 onwards. The test is not whether you crossed the threshold last year. It is whether you have crossed it in any financial year since 2017-18. A business that touched ₹6 crore in 2022-23 and has since fallen to ₹3 crore remains within e-invoicing. There is no exit on the way down.
Once in, always in. There is no mechanism to come out because turnover has fallen.
If you are unsure of your status, the e-invoice portal has an enablement check by GSTIN. It is worth confirming rather than assuming. Being enabled is not the same as being liable, and the legal test is the turnover test rather than the portal flag, but a mismatch between the two is a signal to look more closely.
What it applies to, and what it does not
e-Invoicing covers B2B supplies, supplies to government departments, exports and deemed exports. It covers credit notes and debit notes against those supplies, which is a point that is missed regularly. A credit note against an e-invoiced supply needs its own IRN.
It does not apply to B2C supplies. Businesses above ₹500 crore have a separate dynamic QR code requirement for B2C, which is a different obligation.
Some categories are exempt from e-invoicing regardless of turnover: banks and financial institutions including non-banking financial companies, insurers, goods transport agencies supplying road transport services, passenger transport services, admission to cinematograph exhibition in multiplex screens, special economic zone units, and government departments and local authorities.
Note that the exemption for a special economic zone attaches to SEZ units, not to SEZ developers. Developers are covered.
The 30-day limit
Since 1 April 2025, taxpayers with aggregate annual turnover of ₹10 crore and above cannot report a document on the Invoice Registration Portal more than 30 days after the document date.
The portal enforces it. On day 31, the upload is rejected. There is no late fee that fixes it, no waiver to apply for, and no facility to backdate.
The consequences follow from Rule 48(5). If the document is one to which e-invoicing applies and it never obtained an IRN, then in law there is no invoice. That leads to three separate problems.
Your customer cannot claim the credit. Section 16(2)(a) requires possession of a tax invoice. If the document is not an invoice, the condition is not satisfied. The customer will notice, and the commercial conversation that follows is not a pleasant one.
Your outward reporting is inconsistent. e-Invoiced documents flow automatically into GSTR-1. A supply reported without an IRN sits differently, and the mismatch surfaces later.
The supply itself is not undone. You still made a taxable supply and you still owe the tax. What you have lost is the ability to give your customer a valid document for it.
The scenarios that generate this are ordinary rather than exotic: a month-end invoice raised in the ERP but not pushed to the IRP because the integration failed silently, a document held back during a dispute over quantity, an invoice raised in a branch that does not realise the group is covered, or a credit note issued three months after the original invoice and not recognised as needing its own IRN.
The control that actually prevents it
Almost every one of those scenarios is caught by a single daily reconciliation: documents in the ERP against documents with an IRN.
Run it daily, with an ageing bucket. Anything over 20 days old with no IRN is escalated. Anything over 25 is dealt with that day. The 30-day cliff is only dangerous if nothing is watching the approach to it.
The failure that produces most of the real damage is a silent integration error. An API call that fails and is logged but not alerted on will accumulate weeks of unreported invoices before anyone notices, and by then the earliest ones are past saving. An error that is only written to a log is not monitored. It needs to raise something a person will see.
Practical points
The IRN is generated by the portal, not by you. You upload the particulars in FORM GST INV-01, and the IRP returns the IRN, a signed QR code and a digitally signed invoice. Printing your own QR code is not e-invoicing.
Cancellation is 24 hours, and only whole. An e-invoice can be cancelled on the IRP within 24 hours of generation, and only in full. After that, corrections happen through a credit note, which itself needs an IRN. Design the approval flow so that errors are caught before upload rather than after.
Amendments happen in GSTR-1, not on the IRP. The IRP has no amendment facility.
e-Way bills can be generated from the same upload. Where transport details are supplied along with the invoice particulars, the e-way bill is generated together with the IRN, which removes a duplicate data entry step and a source of inconsistency between the two documents.
Test the integration against the sandbox before go-live, and re-test after any ERP upgrade. Version changes in invoicing modules break IRP integrations quietly and regularly.
The summary
The threshold is ₹5 crore of aggregate turnover at PAN level, tested against any financial year since 2017-18, with no exit if turnover falls. It covers B2B, government supplies, exports and the credit and debit notes against them. From 1 April 2025, taxpayers at ₹10 crore and above have 30 days from the document date to report, and the portal will not accept anything later. Rule 48(5) then makes an unreported document a non-invoice, which is your customer’s credit problem and your commercial problem. Reconcile ERP documents against IRNs daily, alert on integration failures rather than logging them, and treat day 20 as the deadline rather than day 30.
