E-invoicing under GST requires eligible taxpayers to obtain Invoice Reference Number (IRN) from the Invoice Registration Portal (IRP) before issuing B2B invoices. The system validates invoice data and generates QR code for authentication.
Thresholds for mandatory e-invoicing have been progressively reduced; many mid-size businesses must integrate ERP with GSP or direct API. Non-compliance invalidates ITC for recipients and attracts penalties.
This article covers applicability, process flow, and implementation tips.
Applicability (verify current threshold)
E-invoicing is mandatory for registered persons whose aggregate turnover in any preceding financial year exceeds the notified limit (₹5 crore for many periods — check latest CBIC notification). Applies to B2B supplies, exports, and deemed exports; certain documents excluded.
- Includes supplies to SEZ, exports, and RCM supplies where notified.
- Excludes B2C invoices, bills of supply in specified cases, and documents listed in notifications.
- Credit/debit notes linked to e-invoices also require IRN where applicable.
Process flow
- Generate invoice JSON in prescribed schema from billing software.
- Submit to IRP via GSP or direct API; receive IRN, Ack No., and signed QR code.
- Print or embed QR on PDF invoice shared with customer.
- Details auto-flow to GSTR-1 — reduce manual entry errors.
- Cancel IRN within 24 hours if error; no deletion after 24 hours — issue credit note.
Integration architecture
| Component | Role |
|---|---|
| ERP / billing | Master data, invoice creation, JSON export |
| GSP | Connectivity to IRP, error handling, retries |
| IRP (NIC) | Validation, IRN generation, duplicate check |
Common errors and controls
- GSTIN mismatch between supplier and buyer master.
- Incorrect HSN, place of supply, or document type code.
- Duplicate invoice numbers across financial years.
- Failure to generate IRN before movement of goods on e-way bill integration.
E-invoice and e-way bill
Part-A of e-way bill may auto-populate from e-invoice for many taxpayers. Align logistics cut-off times with IRP downtime (scheduled maintenance).
General professional information only. E-invoice thresholds and schemas change by notification; verify CBIC updates before go-live.