GST E-Invoicing Guide: Who Needs It, Process, IRP, Common Errors (2026)
GST e-invoicing guide — who needs it, IRP, NIC portal, common errors, format. From ₹1,499. CA-led.
E-invoicing under GST is mandatory for businesses with aggregate turnover > ₹5 crore. In this guide, we cover the eligibility, process, IRP, common errors, and integration.
What is GST E-Invoicing?
E-invoicing is a system where all B2B invoices are generated through a government-accredited Invoice Registration Portal (IRP). The IRP validates the invoice + generates a unique Invoice Reference Number (IRN) + QR code. The IRN is linked to the GST portal + GSTR-1.
Who Needs E-Invoicing?
- All businesses with aggregate turnover > ₹5Cr in any FY since 2017-18
- For B2B invoices (not B2C)
- Also for: exports, SEZ supplies, reverse charge invoices, credit / debit notes
- Voluntary: any business can opt in (recommended for B2B)
E-Invoice Process
- Step 1: Create invoice in your accounting / ERP software (Tally, Zoho, SAP, etc.)
- Step 2: Push the invoice to the IRP (via API or utility)
- Step 3: IRP validates (HSN, GSTIN, amount, etc.)
- Step 4: IRP generates IRN (Invoice Reference Number) + QR code
- Step 5: IRN is stored in GST portal + your accounting software
- Step 6: Invoice is auto-populated in GSTR-1 (no manual entry)
Invoice Registration Portals (IRPs)
Currently, NIC (National Informatics Centre) operates the only IRP — einvoice1.gst.gov.in. Future: multiple IRPs may be authorised.
Common E-Invoice Errors
- Invalid GSTIN (supplier or buyer GSTIN is wrong)
- Invalid HSN code (HSN must be 4+ digits for turnover > ₹5Cr, 6 digits for > ₹5Cr)
- Missing / wrong tax amount
- Duplicate invoice number
- Invoice date is in the future
- Total amount mismatch
- Wrong place of supply (POS)
- Unit of measurement (UOM) is wrong
- Reverse charge flag missing
How to Generate E-Invoices
Option 1: Direct on IRP Portal
Login to einvoice1.gst.gov.in → Create invoice → Fill details → Submit. Limited to a few invoices per day. Suitable for micro businesses.
Option 2: Tally with e-invoicing API
Tally Prime has built-in e-invoicing support. Configure TDL + GST API → push invoices to IRP automatically. Suitable for businesses already using Tally.
Option 3: Zoho Books / QuickBooks / Other
Zoho Books, QuickBooks, Busy, and other software have built-in e-invoicing. Just enable it + push invoices to IRP.
Option 4: Third-party API integration
Use Cleartax, Masters India, IRIS, or other GST API providers. Integrate with your ERP / website / e-commerce platform.
Integration with Accounting Software
| Software | E-invoice Support | Setup |
|---|---|---|
| Tally Prime | Built-in (TDL) | Enable in Tally + enter GST API credentials |
| Zoho Books | Built-in | Enable in Settings + auto-push to IRP |
| QuickBooks | Third-party API | Integrate via Cleartax / Masters India |
| SAP / Oracle | Custom integration | SAP connector + API |
| Busy | Built-in | Enable in Busy + push to IRP |
Cost
| Service | Cost |
|---|---|
| E-invoice setup in Tally / Zoho / QuickBooks | From ₹1,499 |
| E-invoice API integration (third-party) | From ₹4,999 |
| E-invoice API + ERP customisation | From ₹14,999 |
| E-invoice + e-way bill + reconciliation | From ₹9,999 |
Frequently Asked Questions
Q: What is the turnover threshold for e-invoicing?
A: Aggregate turnover > ₹5Cr in any FY from 2017-18 onwards. E-invoicing is mandatory for such businesses for all B2B invoices.
Q: Is e-invoicing mandatory for B2C invoices?
A: No. Only for B2B. B2C invoices can be generated normally (with sequential numbering + HSN + tax breakdown).
Q: What is the difference between e-invoice and e-way bill?
A: E-invoice: GST invoice registered with IRP. Mandatory for B2B. E-way bill: required for movement of goods > ₹50,000. Both are separate requirements.
Q: What is IRN?
A: Invoice Reference Number — a unique 64-character hash generated by the IRP for each e-invoice. Contains the invoice details + acts as proof of registration with the IRP.