What SMBs Must Do for Mandatory E-Invoicing from April 2026

E-invoicing has been mandatory for businesses whose aggregate annual turnover (AATO) exceeded Rs 5 crore in any financial year from 2017-18 onwards since 1 August 2023 (Notification 10/2023-Central Tax). There was no separate exemption for the Rs 5 to 10 crore band that ended in April 2026.

If your turnover crossed Rs 5 crore for the first time in FY 2025-26, e-invoicing applies to you from 1 April 2026. From then on, every B2B invoice your business issues must be registered on the Invoice Registration Portal (IRP) and carry a valid Invoice Reference Number (IRN) and QR code.

This guide is for businesses that are generating e-invoices for the first time.

Why This Affects You Now

The e-invoicing threshold was lowered in stages from Rs 500 crore (October 2020) to Rs 5 crore (1 August 2023).

If your business crossed the Rs 5 crore AATO mark in any financial year from FY 2017-18 through FY 2025-26, e-invoicing is mandatory. The threshold is based on your highest turnover in any year, not just the most recent year.

What Exactly Is E-Invoicing

E-invoicing does not mean creating invoices on a computer. It means every B2B invoice must be:

1. Generated in a standard JSON format
2. Uploaded to the Invoice Registration Portal (IRP)
3. Validated and assigned a unique Invoice Reference Number (IRN)
4. Digitally signed by IRP
5. Returned with a QR code that you print on the invoice

The physical invoice your buyer receives looks the same, but it now carries an IRN and QR code that link it to the GST system. This ensures the invoice is authentic and automatically flows into your GSTR-1 and your buyer's GSTR-2B.

Step-by-Step: Getting Started with E-Invoicing

Step 1: Check Your Eligibility

Log in to the GST portal and review your GSTR-3B filings to confirm your aggregate turnover. Remember, AATO includes turnover across all GSTINs registered under the same PAN.

Step 2: Register on IRP

Visit einvoice1.gst.gov.in. Most eligible GSTINs are auto-registered. Log in using your GST portal credentials. If your GSTIN is not registered, submit a registration request.

After login, you will see your dashboard with options for generating invoices, viewing generated IRNs, and downloading reports.

Step 3: Choose Your Method

You have three options for generating e-invoices:

Option A: Direct portal entry. Log in to IRP and enter invoice details one at a time. This works for businesses issuing fewer than 10 to 15 invoices per month.

Option B: Bulk upload via Excel/JSON. Download the IRP template, fill in invoice details in bulk, and upload. Suitable for 15 to 100 invoices per month.

Option C: API integration with billing software. Your accounting or ERP software connects directly to IRP and generates IRNs automatically when you create an invoice. This is the best option for any business issuing more than 15 invoices per month.

Step 4: Set Up API Credentials (For Software Integration)

If using Option C:

1. Log in to the IRP portal
2. Go to API Registration
3. Create your Client ID and Client Secret
4. Share these credentials with your software provider
5. Your provider configures the integration

Most popular accounting packages (Tally, Zoho Books, Busy, Marg) have built-in e-invoicing modules. Contact your vendor to enable the module and enter your API credentials.

Step 5: Test in Sandbox

Before generating real e-invoices:

• Use the IRP sandbox environment for testing
• Generate 5 to 10 test invoices covering different scenarios (different tax rates, inter-state vs intra-state, with and without cess)
• Verify that IRN is generated correctly
• Check that QR code prints properly on your invoice format
• Test cancellation workflow

Step 6: Go Live

Switch from sandbox to production mode. From this point, every B2B invoice must go through IRP.

The 30-Day IRP Reporting Limit

There is no 7-day upload rule. The time limit that does exist is this:

• From 1 April 2025, businesses with AATO of Rs 10 crore or more cannot report an invoice, credit note or debit note on the IRP more than 30 days after the document date. The IRP rejects it.
• For businesses with AATO below Rs 10 crore, no such reporting window has been notified so far.
• In every case, Rule 48(4) requires the invoice to be prepared with the IRN. An invoice issued without it is not a valid tax invoice (Rule 48(5)), so the buyer's ITC is at risk.

The safe practice is to generate the IRN at the time you issue the invoice, not in a batch later.

How to Stay on Time

• If using API integration, invoices are uploaded automatically at the time of creation. No additional action needed.
• If using bulk upload or portal entry, generate the IRN before you hand over or send the invoice, so the printed invoice carries the IRN and QR code

Common Mistakes First-Time E-Invoicing Businesses Make

1. Forgetting Credit Notes and Debit Notes

E-invoicing applies to B2B credit notes and debit notes too. Every credit note reducing an original invoice must be uploaded to IRP with its own IRN.

2. Using Wrong HSN Codes

IRP validates HSN codes. Businesses with AATO above Rs 5 crore must show at least 6-digit HSN codes on their invoices (Notification 78/2020-Central Tax), so an invalid or short code will cause errors.

3. Not Training the Billing Team

Your accountant or billing staff need to understand the new workflow. Common errors: generating invoices without uploading to IRP, using old invoice formats without IRN/QR code, or issuing manual invoices for urgent deliveries.

4. Ignoring the 24-Hour Cancellation Window

If you need to cancel an e-invoice, it must be done on IRP within 24 hours. After 24 hours, you cannot cancel on IRP and must issue a credit note instead. Many businesses discover this too late.

5. Not Checking IRN Status

After uploading, verify that the IRN was successfully generated. Failed uploads (due to validation errors) mean the invoice is not registered. Your buyer will not see it in their GSTR-2B.

6. Treating E-Invoicing as Optional

Some businesses in the newly eligible bracket assume they can delay compliance. There is no grace period. Once e-invoicing applies to you, every B2B invoice without a valid IRN is non-compliant and attracts penalties.

Impact on Your Business Operations

Positive Changes

• Your invoices are automatically populated in GSTR-1 (no manual entry)
• Your buyers see your invoices in their GSTR-2B automatically
• Reduced data entry errors
• Better audit trail and documentation

Adjustments Needed

• Invoice generation takes slightly longer due to IRP communication
• Internet connectivity is required for real-time e-invoice generation
• Invoice format must include IRN and QR code fields
• Staff training is required

Fallback for Internet Issues

If your internet is down and you need to issue an invoice:

• Issue the invoice with all mandatory details
• Upload to IRP as soon as connectivity is restored (and in any case within 30 days if your AATO is Rs 10 crore or more)
• Do not wait until month-end to upload pending invoices

Penalties for Non-Compliance

• An invoice issued without an IRN is not treated as a valid invoice (Rule 48(5)). Under Section 122(1) of the CGST Act, the penalty is Rs 10,000 or the tax involved, whichever is higher
• Your buyer's ITC on invoices without a valid IRN is at risk
• Repeated non-compliance may trigger GST audit proceedings

Let Tax Garden Set Up Your E-Invoicing

Transitioning to e-invoicing for the first time involves IRP registration, software configuration, team training, and process changes. Tax Garden's Compliance Standard plan covers the complete setup and ongoing management for newly eligible businesses.

Frequently Asked Questions

My turnover crossed Rs 5 crore this year. When do I have to start e-invoicing?

E-invoicing applies from the financial year after the one in which aggregate turnover first exceeds Rs 5 crore. For example, if turnover crossed Rs 5 crore in FY 2025-26, e-invoices are required from 1 April 2026. Turnover is counted across all GSTINs under the same PAN, so check the combined figure.

Does it cost anything to generate e-invoices on the IRP?

No. Generating IRNs on the government IRP (einvoice1.gst.gov.in) is free, including direct entry on the portal and the offline bulk upload tool. Costs arise only if you use paid accounting software or a private IRP with added features. Small businesses issuing a few invoices a month can manage on the free portal.

Do I still have to file GSTR-1 after moving to e-invoicing?

Yes. E-invoice details auto-populate the B2B, export and credit or debit note tables of GSTR-1, but you must still review the draft and file the return by the due date. B2C sales, nil-rated supplies and HSN summaries need to be completed by you.

Can I generate the e-way bill along with the e-invoice?

Yes. When the IRN is generated, Part A of the e-way bill is filled from the e-invoice data. If you also give transport details such as vehicle number or transporter ID, the e-way bill can be generated in the same step, saving duplicate data entry.

Are sales to unregistered customers covered by e-invoicing?

No. E-invoicing covers supplies to registered businesses, exports and SEZ supplies, plus the related credit and debit notes. Invoices to unregistered consumers (B2C) are issued in the normal way and reported in GSTR-1. Keep the two invoice series separate in your billing software to avoid mistakes.