E-invoice software for GST: IRN, QR codes and what to look for
How GST e-invoicing works, who has to do it, and the checks that matter when you choose e-invoice software, plus where ERPStack fits.
Last updated 21 October 2026
What is e-invoice software?
E-invoice software prepares your GST invoices, credit notes and debit notes in the government e-invoice format, sends them to an Invoice Registration Portal (IRP), and gets back the Invoice Reference Number (IRN) and signed QR code that must appear on the invoice. Businesses whose aggregate turnover crossed ₹5 crore in any year from 2017-18 must use it for B2B invoices.
Where ERPStack is today
ERPStack is in development. It is not yet available to download or buy, and the features on this page are planned, not shipped.
Sign upWho has to use e-invoice software?
E-invoicing is compulsory for a registered business whose aggregate turnover crossed ₹5 crore in any financial year from 2017-18 onwards. That is the threshold set by Notification 10/2023-Central Tax, in force from 1 August 2023 (listed on the e-invoice portal’s notifications page). Turnover is counted across every GSTIN under the same PAN, and once you are in, you stay in even if turnover later falls.
A few kinds of businesses are exempt even above the threshold, including banks, insurers, NBFCs, goods transport agencies, passenger transport services and SEZ units. If your business is near the line, check the notifications yourself or ask your CA.
| Document | Needs an IRN? |
|---|---|
| Tax invoice to a registered business (B2B) | Yes |
| Export invoice, with or without payment of tax | Yes |
| Credit note or debit note on a B2B supply | Yes |
| Invoice to an unregistered consumer (B2C) | No |
| Delivery challan, bill of supply | No |
How does GST e-invoicing work?
The invoice is still created in your own software. E-invoicing adds a registration step before the invoice is valid. Under CGST Rule 48(4), an invoice from a business in scope that skips this step is not treated as an invoice at all.
- Create the invoice in your billing or ERP software as usual.
- Prepare the e-invoice data in the government schema (form GST INV-01, sent as JSON).
- Upload it to an IRP, either directly through the portal’s API or through a GST Suvidha Provider (GSP).
- The IRP validates it, generates the Invoice Reference Number (IRN), digitally signs the data and returns a signed QR code.
- Print or send the invoice with the QR code, as Rule 46(r) requires.
- The data flows on to your GSTR-1 and, where details are given, to the e-way bill system, so you key it in once.
The 30-day reporting limit
From 1 April 2025, businesses with aggregate annual turnover of ₹10 crore or more cannot report an invoice, credit note or debit note to the IRP more than 30 days after its date; the portal rejects it (IRP notice). Good e-invoice software should warn you about documents that are close to the limit.
What should you look for in e-invoice software?
| Check | Why it matters |
|---|---|
| IRN from inside your billing screen | Generating the IRN where the invoice is made avoids re-typing and mismatches |
| Bulk generation | Month-end batches of hundreds of invoices should not be clicked through one by one |
| Validation before upload | Catching wrong GSTINs, HSN codes or state codes early saves rejected uploads |
| Credit and debit notes | They need IRNs too and must link back to the original invoice |
| Cancellation inside the allowed window | Mistakes happen; cancelling should be one step, not a portal visit |
| 30-day alerts | Needed if your turnover is ₹10 crore or more |
| E-way bill from the same data | Avoids entering transport details twice |
| Multiple GSTINs | Businesses registered in several states need one place for all of them |
Also check who stands behind the connection. Software either talks to the IRP directly or through a GSP, and you should know which, what happens when the portal is slow, and how failed uploads are retried.
Where does ERPStack fit?
ERPStack is an ERP Perimattic is building for Indian small and mid-sized businesses. E-invoicing is planned as part of its billing module, not a separate tool: invoices, credit notes and e-way bills will be created from the same sales records, with e-invoice data prepared in the government schema and IRNs generated through a GSP.
Status: ERPStack is in development and IRN generation is not live yet, because it needs a GSP connection that is still being set up. If e-invoicing is your first need, sign up and mention e-invoicing when we get in touch. For the wider picture, read what GST billing software should do.
This page is general guidance, not tax or legal advice. Rules were checked on 21 October 2026.
E-invoicing, answered
Is e-invoicing mandatory for my business?
It is mandatory if your aggregate turnover, counted across all GSTINs under the same PAN, crossed ₹5 crore in any financial year from 2017-18 onwards. That threshold applies from 1 August 2023 under Notification 10/2023-Central Tax. Some sectors, such as banks, insurers and goods transport agencies, are exempt, so check the notifications on the e-invoice portal for your case.
Does e-invoicing apply to B2C invoices?
No. The e-invoice (IRN) requirement covers supplies to registered businesses (B2B), exports and the related credit and debit notes. Invoices to unregistered consumers (B2C) are not reported to the IRP for an IRN.
Can ERPStack generate IRNs today?
Not yet. ERPStack is in development, and IRN generation depends on a live connection to the e-invoice system through a GST Suvidha Provider (GSP), which is still being set up. Treat ERPStack’s e-invoicing as coming soon, and sign up to be told when it is ready.
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