E-Invoicing Under GST: Who Must Comply and How to Implement

A practical guide for Indian businesses on understanding the e-invoicing mandate, checking your eligibility, and setting up a compliant workflow — step by step.

"E-invoicing is not just a compliance requirement — it is the GST system reading your invoices before your buyer does. Get it right at the source."

What is E-Invoicing Under GST?

E-invoicing means reporting your B2B invoices to the GST Invoice Registration Portal (IRP) in real time, receiving a unique Invoice Reference Number (IRN) and a digitally signed QR code, and then sharing that authenticated invoice with your buyer. The IRP validates each invoice, registers it on the GST network, and auto-populates it into your GSTR-1 and your buyer's GSTR-2B — eliminating manual data entry and reducing ITC mismatches at source.

Who Must Comply? Turnover Thresholds

Phase	Effective Date	Turnover Threshold	Status
Phase 1	October 2020	> ₹500 Crore	Active
Phase 2	January 2021	> ₹100 Crore	Active
Phase 3	April 2021	> ₹50 Crore	Active
Phase 4	October 2022	> ₹10 Crore	Active
Phase 5	August 2023	> ₹5 Crore	Current

The threshold is based on aggregate annual turnover in any preceding financial year from 2017–18 onwards. If your turnover exceeded ₹5 crore in any year since GST was introduced, e-invoicing applies to you now.

Step-by-Step: How to Implement E-Invoicing

Check your applicability — Look up your aggregate annual turnover for each year from 2017–18. Confirm under your taxpayer profile on the GST portal.
Choose your mode of integration — (a) direct API integration from your ERP, (b) a GST Suvidha Provider (GSP), or (c) the IRP's own offline tool for low-volume filers.
Register on the e-invoice portal — Visit einvoice1.gst.gov.in. Log in with your GST credentials and enable e-invoicing for your GSTIN.
Configure your invoicing software — Ensure your ERP can generate invoices in the required JSON schema. Map all mandatory fields including GSTIN, HSN/SAC codes, and place of supply.
Test on the sandbox environment — The GST sandbox lets you generate test IRNs without affecting your live returns.
Go live — Every B2B tax invoice, credit note, and debit note must pass through the IRP before it is shared with the buyer.
Handle cancellations within 24 hours — An e-invoice can only be cancelled on the IRP within 24 hours of generation. After that, you must issue a credit note.

Key Benefits of E-Invoicing

Benefit	What It Means for Your Business
Auto-populated returns	GSTR-1 data flows from IRP directly, cutting manual entry errors to near zero.
Fewer ITC mismatches	Buyer's GSTR-2B is pre-filled, reducing reconciliation disputes at source.
Faster audit readiness	Every invoice is registered and traceable on the GST network in real time.
Easier invoice financing	Banks and NBFCs use IRN-validated invoices for faster trade finance and discounting.

Penalties for non-compliance: Invoice is treated as invalid — buyer cannot claim ITC. Penalty of ₹10,000 per invoice under Section 122 of the CGST Act. 100% penalty on the tax amount for invoices issued to fraudulently claim ITC.

Quick Summary

E-invoicing under GST is mandatory for all businesses with aggregate turnover above ₹5 crore. The process — generate invoice, upload to IRP, receive IRN and QR code, share with buyer — is straightforward once your software is configured. Start with the sandbox, get your integration right, and go live before the next billing cycle.

e-invoicing GST IndiaIRP registrationIRN generationGSTR-1 auto-populationGST e-invoice threshold

Need help implementing e-invoicing? Contact BNKS & Associates for GST compliance support.