GST E-Invoicing — IRN, QR Code & Compliance Guide
Complete guide to GST e-invoicing: who must comply (₹5 crore+ turnover), how IRN generation works, QR code requirements, auto-population of GSTR-1, cancellation rules, penalties for non-compliance, and integration with billing software.
₹5 Cr
Current Threshold
Aug 2023
Effective From
IRP (NIC)
Portal
IRN
Unique ID
24 Hours
Validity
JSON Schema
Format
B2B Only
Applies To
Mandatory
QR Code
How E-Invoicing Works
What is E-Invoicing?
E-Invoicing is the electronic authentication of GST invoices by uploading invoice data to the government's Invoice Registration Portal (IRP). The IRP validates, assigns a unique Invoice Reference Number (IRN), digitally signs it, and returns a QR code. It's NOT a government-generated invoice — businesses create invoices normally, then register them.
Threshold History & Current Limit
Started with ₹500 crore (Oct 2020), then ₹100 crore (Jan 2021), ₹50 crore (Apr 2021), ₹20 crore (Apr 2022), ₹10 crore (Oct 2022), and ₹5 crore (Aug 2023). The government progressively lowered the threshold to bring more businesses under e-invoicing compliance.
IRN — Invoice Reference Number
Each e-invoice gets a unique 64-character IRN generated using SHA-256 hash of: Supplier GSTIN + Invoice Number + Financial Year. IRN is the unique identity of an invoice in the GST system. Duplicate invoice numbers are automatically rejected. IRN is valid for 24 hours from generation.
QR Code on Invoices
Every e-invoice must carry a QR code containing: Supplier GSTIN, Recipient GSTIN, Invoice Number, Date, IRN, Invoice Value, Number of Line Items, and Digital Signature. B2C invoices (for turnover >₹500 crore) need a dynamic QR code for UPI payment. QR enables offline verification.
Auto-Population of Returns
E-invoiced data auto-populates GSTR-1 (outward supply return). No manual entry needed for B2B invoices. The recipient sees these in their GSTR-2B for ITC matching. This eliminates data entry errors, reduces reconciliation issues, and speeds up return filing significantly.
Cancellation & Amendment
An e-invoice can be cancelled on IRP within 24 hours of generation. After 24 hours, cancellation must be done on the GST portal via GSTR-1. Amendments to e-invoices are not possible — you must cancel and issue a new invoice or issue a credit/debit note. Partial cancellation is not allowed.
E-Invoicing Threshold Timeline
| Phase | Turnover Threshold | Applicability |
|---|---|---|
| Phase 1 (Oct 2020) | ₹500 Crore+ | Large enterprises |
| Phase 2 (Jan 2021) | ₹100 Crore+ | Large-medium enterprises |
| Phase 3 (Apr 2021) | ₹50 Crore+ | Medium enterprises |
| Phase 4 (Apr 2022) | ₹20 Crore+ | Mid-size businesses |
| Phase 5 (Oct 2022) | ₹10 Crore+ | Small-medium businesses |
| Phase 6 (Aug 2023) | ₹5 Crore+ | Small businesses (current) |
| Expected Next | ₹1 Crore+ | Micro businesses (proposed) |
Frequently Asked Questions
Who needs to generate e-invoices under GST?
What happens if I don't generate an e-invoice?
Is e-invoicing applicable for B2C transactions?
How do I integrate e-invoicing with my billing software?
E-Invoicing — Built Into Every Invoice
Laabam.One auto-generates IRN via IRP API on every B2B invoice. QR codes, digital signatures, and GSTR-1 auto-filing — all handled seamlessly.
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