GST e-invoicing changed how B2B invoices are issued in India. Instead of an invoice being “final” the moment you print it, a B2B invoice now has to be reported to the government’s Invoice Registration Portal (IRP), which validates it and returns a unique reference. This guide explains the moving parts in plain language.
Thresholds, timelines, and rules change. Always confirm the current requirements on the official GST portal or with your tax advisor before acting on this guide.
What is an e-invoice?
An e-invoice is not a new kind of invoice. It is your normal GST invoice, in a standard JSON format, reported to the IRP. When the IRP accepts it, it returns:
- IRN (Invoice Reference Number) — a unique hash that identifies the invoice.
- Signed QR code — printed on the invoice so anyone can verify it.
- Acknowledgement number and date.
Once registered, the invoice details flow into the GST system, which helps auto-populate returns such as GSTR-1 and supports e-way bill generation.
Who needs to e-invoice?
E-invoicing applies to businesses whose aggregate annual turnover is above the threshold notified by the government. The threshold has been lowered in stages over the years, so many small and mid-sized businesses are now covered. Some categories of businesses are exempt.
At the time of writing, e-invoicing covers B2B invoices, credit and debit notes, and export invoices. B2C invoices generally don’t need an IRN, although some large businesses must print a dynamic QR code on B2C invoices.
The everyday workflow
- Create the invoice in your billing or ERP system as usual.
- Generate the IRN — your system sends the invoice JSON to the IRP, directly or through a GST Suvidha Provider.
- Print or share the invoice with the IRN and signed QR code.
- Generate the e-way bill if goods are moving, often using the same data.
- File returns — e-invoice data feeds your GSTR-1, which you still review and file.
Common mistakes to avoid
- Wrong GSTIN or HSN codes. The IRP validates these, so bad master data means rejected invoices. Clean your customer and item masters first.
- Cancelling too late. An IRN can only be cancelled within a short window after generation. After that, you need a credit note.
- Duplicate invoice numbers. The IRP rejects a document number already used in the same financial year.
- Treating e-invoicing as an afterthought. If staff copy invoices into a separate portal by hand, errors creep in. Generating the IRN from the billing system itself avoids double entry.
How software helps
A GST-ready ERP keeps the invoice, IRN, QR code, e-way bill, and returns registers connected. In InxSuite ERP, sales invoices carry the e-invoice details, and the GSTR registers are built from the same documents — so what you bill is what you report.
If you’re evaluating software, ask:
- Can it generate the IRN from the invoice screen, without re-entry?
- Does it validate GSTIN and HSN before submission?
- Can it produce e-way bill data from the same invoice?
- Are GSTR-1 and 3B registers available as reports?