GST E-Invoicing Explained: Coverage, IRN Generation, Reporting Deadline and Consequences of Default
This article answers the questions practitioners are most often asked on e-invoicing under Rule 48 of the CGST Rules, 2017, covering the turnover thresholds, the working of the Invoice Registration Portal, the 30-day reporting limit and the effect of default on the supplier and the recipient.
The turnover threshold now stands at Rs 5 crore, and from 1 April 2025 a hard time limit applies to larger assessees. A missed or late IRN is not a procedural footnote: under the Rules the document may not count as an invoice at all, which can reach the recipient's input tax credit.
How did e-invoicing come about?
The 35th GST Council meeting (21 June 2019) decided on a phased introduction of e-invoicing, initially on a voluntary basis for B2B supplies. The 37th meeting (20 September 2019) endorsed a model in which businesses continue to use their own accounting systems and report invoice data to a registration portal. Rule 48(4) was inserted by Notification No. 68/2019-Central Tax dated 13 December 2019. The 39th meeting (14 March 2020) recommended certain exemptions and a deferral, which moved the mandatory start to 1 October 2020.
What exactly is an e-invoice?
An e-invoice is not an invoice created electronically. It is an invoice prepared in the supplier's own ERP or billing software, whose data is then reported to an Invoice Registration Portal (IRP) in the schema of FORM GST INV-01 and authenticated by it. On receipt, the IRP:
- validates the data against the prescribed schema;
- runs a duplication check;
- generates a unique Invoice Reference Number (IRN);
- digitally signs the data; and
- returns the signed data with a QR code carrying the IRN and specified particulars.
A PDF, a spreadsheet invoice or an emailed invoice is not an e-invoice merely because it is in digital form. Authentication by the IRP is what makes it one.
What does the law require?
Section 31 of the CGST Act, 2017 imposes the obligation to issue a tax invoice, and Rule 46 prescribes its particulars: supplier and recipient details, a consecutive serial number, date, HSN or SAC, value and tax charged.
Rule 48(4) goes further for a notified class of persons. They must prepare invoices with the prescribed particulars in FORM GST INV-01 and obtain an IRN by uploading the details on the Common GST Electronic Portal. The class is specified in Notification No. 13/2020-Central Tax, as amended.