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GST · Intermediate · 7 min read

E-Invoicing Under GST

E-invoicing is mandatory for most B2B transactions in India today. This explains who must comply, how the IRN process works, and the penalties for missing compliance.

What is E-Invoicing?

E-invoicing requires B2B invoices to be authenticated electronically by the Invoice Registration Portal (IRP) before being sent to customers. The IRP issues a unique Invoice Reference Number (IRN) and a QR code that must be printed on the invoice.

Who Must Issue E-Invoices?

Based on aggregate annual turnover (AATO) in any FY from 2017-18 onwards:

Effective fromAATO threshold
1 Oct 2020₹500 crore
1 Jan 2021₹100 crore
1 Apr 2021₹50 crore
1 Apr 2022₹20 crore
1 Oct 2022₹10 crore
1 Aug 2023₹5 crore

Cross ₹5 crore in any FY since 2017-18 and e-invoicing is mandatory for your B2B supplies.

Exempt Categories

  • SEZ units (developers are covered though)
  • Insurance companies, banks, NBFCs
  • Goods Transport Agencies (GTAs)
  • Passenger transportation services
  • Multiplex cinemas
  • Government departments

What's Covered

CoveredNot covered
B2B invoicesB2C invoices
Credit/debit notes (B2B)Bills of supply
Export invoicesSelf-invoices for RCM
SEZ suppliesDelivery challans, job-work challans
Deemed exports

The E-Invoicing Process

  1. Generate invoice in JSON schema — your software outputs the standardised format
  2. Upload to IRP via API or portal (einvoice1 through einvoice6.gst.gov.in)
  3. IRP validates and returns IRN, signed QR code, acknowledgement number
  4. Print IRN and QR on the final invoice — without these the invoice is legally invalid
  5. Auto-population — data flows to GSTR-1, buyer's GSTR-2B, and e-way bill Part A

Time Limit for IRN

Taxpayers with AATO ₹100 crore+ must generate IRN within 30 days of invoice date. Beyond 30 days the IRP rejects the request. For smaller taxpayers no hard deadline, but immediate generation is best practice.

Penalties

  • Invoice without IRN where required — treated as no invoice; recipient can't claim ITC; ₹10,000 penalty or 100% of tax (whichever higher)
  • Detention of goods in transit if e-invoice IRN not generated
  • GSTR-1 mismatch notices if non-IRN invoices reported

How to Implement

ApproachBest forEffort
Manual on IRP portal<10 invoices/day2–3 min per invoice
Excel offline tool10–50 invoices/dayBatch upload
API integration via software50+ invoices/dayZero — auto on invoice save
In iAccounting

iAccounting has direct API integration with IRP. Save a B2B sales invoice → IRN and QR generated and printed in 1.5 seconds. Full audit trail preserved for 8 years.

See e-invoicing →

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