Over 20,000 Indian businesses received GST notices in the last financial year for failing to generate e-invoices when required. The penalty? Up to ₹25,000 per invoice under Section 122 of the CGST Act, 2017 - plus the inability to claim Input Tax Credit on those transactions. With the e-invoice turnover threshold dropping again in 2026, thousands more businesses are now in scope. If you are unsure whether your business needs to comply, this guide breaks down exactly who needs e-invoicing, what the current limits are, and how to get compliant before a notice lands on your desk.

What Is E-Invoicing Under GST and Why Does It Matter?

E-invoicing under GST is not about generating invoices on a computer. It is a system where your invoice data is reported to the Invoice Registration Portal (IRP) operated by the National Informatics Centre (NIC), which validates the data, assigns a unique Invoice Reference Number (IRN), and digitally signs the invoice with a QR code.

This was introduced through Notification No. 13/2020 – Central Tax dated 21st March 2020, under Rule 48(4) of the CGST Rules, 2017. The system serves three purposes for the government:

For businesses, it means one thing: if you cross the threshold and do not generate e-invoices, your invoices are technically invalid under GST law, and your buyers cannot claim ITC on them.

The 2026 Turnover Threshold: Who Must Comply Now?

The e-invoice mandate has been rolled out in phases since October 2020, with the turnover threshold progressively lowered:

As of 2026, any business registered under GST with an aggregate annual turnover exceeding ₹1 crore in any financial year from 2017-18 onwards must generate e-invoices for all B2B supplies.

Critical point: The threshold is based on aggregate turnover across all GSTINs under the same PAN. If you have three branches with ₹40 lakh turnover each, your aggregate is ₹1.2 crore - and you are covered.

Who Is Exempt?

Not every registered person needs to comply. The following are excluded under Notification No. 13/2020 (as amended):

If you are not in this exempt list and your turnover crosses ₹1 crore, you must generate e-invoices.

What Happens If You Do Not Comply: Penalties and Business Impact

The consequences of skipping e-invoicing go beyond just a fine. Here is what is at stake:

Penalty Under Section 122 of CGST Act

If you issue an invoice without generating an IRN when required, it constitutes issuance of an incorrect invoice. The penalty under Section 122(1)(ii) is:

For a business issuing 50 invoices a month, that could mean ₹5 lakh in penalties per month.

ITC Denial for Your Buyers

Under Rule 48(5) of the CGST Rules, an invoice issued without an IRN (when e-invoicing applies) is not a valid tax invoice. This means:

This is often the bigger risk - losing B2B customers because your invoices are non-compliant.

Auto-Population Failure

Without e-invoicing, your invoice data will not auto-populate in GSTR-1. This means:

E-Way Bill Complications

If you are required to generate e-invoices, the e-way bill Part A is auto-populated from the e-invoice data. Without a valid IRN, your e-way bill generation will also fail, which can lead to goods being detained in transit under Section 129 of the CGST Act.

How to Set Up E-Invoicing: Step-by-Step Process

Step 1: Register on the Invoice Registration Portal

Go to the NIC e-invoice portal (einvoice1.gst.gov.in). You need:

Registration is free. Complete it at least two weeks before you start generating e-invoices so you can test the integration.

Step 2: Choose Your Integration Method

There are three ways to connect with the IRP:

  1. Direct API integration - Your ERP or billing software connects directly to the NIC API. Best for businesses with in-house tech teams or those using large ERP systems like Tally, SAP, or Zoho.
  2. GSP (GST Suvidha Provider) route - You use an authorised GSP like ClearTax, Masters India, or EWay Bill GSP to handle the API calls. Good for mid-size businesses without dedicated IT staff.
  3. Bulk upload via the portal - You generate a JSON file from your billing software and upload it manually on the NIC portal. Works for small businesses with low invoice volumes, but is not practical if you issue more than 20-30 invoices a day.

Step 3: Map Your Invoice Fields

The e-invoice schema (based on the PEPPOL standard) requires specific fields. Ensure your billing system captures:

The most common rejection reason on the IRP is incorrect HSN codes. Audit your product master data before going live.

Step 4: Test with the Sandbox

NIC provides a sandbox environment at einvoice1.gst.gov.in (sandbox mode) where you can test your integration without generating real IRNs. Run at least 50 test invoices covering:

Step 5: Go Live and Monitor

Once testing is complete, switch to the production API. Monitor the following daily for the first two weeks:

Common Mistakes That Trigger Notices (and How to Avoid Them)

Based on patterns from GST notices issued in 2024-25, here are the mistakes that get businesses caught:

Mistake 1: Not Counting All GSTINs Under One PAN

A textile manufacturer in Surat had three GST registrations across Gujarat. Each unit had turnover of ₹60-70 lakh. The aggregate was ₹1.9 crore. The business assumed each registration was independent. It was not. The department issued a notice for 14 months of non-compliant invoices.

Fix: Add up turnover across all GSTINs under your PAN. If the total crosses ₹1 crore in any year since 2017-18, you are covered.

Mistake 2: Generating E-Invoices Late

The IRP does not allow e-invoice generation for invoices older than 30 days from the invoice date (restricted from the earlier 7-day window to 30 days via Notification No. 12/2024). If you forget to generate the IRN within this window, you cannot generate it at all for that invoice.

Fix: Generate the IRN at the point of invoicing, not as a batch job at the end of the day or week. Real-time integration is the safest approach.

Mistake 3: Ignoring Debit and Credit Notes

E-invoicing applies to debit notes and credit notes too, not just regular invoices. Many businesses generate IRNs for invoices but issue manual credit notes. These are invalid.

Fix: Ensure your billing workflow generates IRNs for credit notes and debit notes linked to the original invoice.

Mistake 4: Wrong Document Type Codes

The e-invoice schema uses specific codes: INV for invoices, CRN for credit notes, DBN for debit notes. Using the wrong code causes rejections or incorrect reporting in GSTR-1.

Fix: Map your internal document types to the correct e-invoice type codes in your billing software settings.

Mistake 5: Not Printing the QR Code

Every e-invoice must carry a QR code that contains the signed invoice data. Even if you generate the IRN, if your printed invoice does not carry the QR code, it can be treated as non-compliant during a physical verification.

Fix: Update your invoice print template to include the QR code returned by the IRP.

Compliance Calendar: Key Dates and Actions

Use this checklist to stay on track:

Frequently Asked Questions

Is e-invoicing mandatory for B2C transactions?

No. As of 2026, e-invoicing is mandatory only for B2B supplies, B2B exports, and supplies to SEZ units/developers. B2C invoices are not covered. However, the government has indicated that B2C e-invoicing may be introduced in future phases.

My turnover was above ₹1 crore in 2019-20 but has been below that since. Do I still need to comply?

Yes. The threshold check is based on aggregate turnover in any financial year from 2017-18 onwards. If you crossed ₹1 crore even once, you are permanently covered unless a specific exemption notification is issued.

Can I cancel an e-invoice after generating the IRN?

Yes, but only within 24 hours of generation. After 24 hours, you must issue a credit note (which also needs an IRN) to reverse the transaction. Cancellation is done through the same API or portal used for generation.

What if my billing software does not support e-invoicing?

You need to either upgrade your software or switch to one that supports NIC API integration. Most popular accounting software in India - Tally Prime, Zoho Books, Busy, Marg ERP - now support e-invoicing. If you use custom software, your developer needs to integrate with the NIC API (documentation is available on the e-invoice portal).

Do freelancers and consultants need e-invoicing?

If you are registered under GST and your aggregate turnover exceeds ₹1 crore, yes. The mandate applies to all registered persons issuing B2B invoices, regardless of whether you are a company, partnership, proprietorship, or individual professional.

What is the time limit for generating an IRN?

As per the latest rules, the IRN must be generated within 30 days of the invoice date. After 30 days, the portal will not accept the invoice. This makes it essential to generate IRNs in real-time rather than in bulk.

Does e-invoicing replace the need to file GSTR-1?

No. E-invoicing auto-populates your GSTR-1 data, but you still need to review and file the return. The auto-populated data may need corrections (for example, amendments to previously reported invoices), and B2C transaction data still needs to be entered manually.

What to Do Right Now

If you have been putting off e-invoicing compliance, the cost of delay is now measurable: ₹10,000+ per non-compliant invoice, loss of ITC for your buyers, and increased departmental scrutiny. The setup process takes less than a week for most businesses.

Here is your three-step action plan:

  1. Check your aggregate turnover across all GSTINs under your PAN for every year since 2017-18
  2. Register on the NIC portal and set up API integration or GSP access
  3. Test thoroughly before going live - incorrect e-invoices cause more problems than no e-invoices

If you are not sure where your business stands on e-invoicing or other GST compliance requirements, run a quick compliance check at complianceradar.in. The platform maps your business profile against applicable regulations and flags gaps before the tax department does.