GST e-invoicing guide for Indian retailers (₹5 crore + threshold)
Last reviewed 2026-05-27 · by the RetailPOS team
India's GST Network (GSTN) mandates e-invoicing for businesses above a turnover threshold that has been progressively lowered since 2020. As of 2026, the threshold is ₹5 crore in any preceding financial year — and the direction is further reduction toward universal coverage. For affected businesses, every B2B invoice must be submitted to the Invoice Registration Portal (IRP) in real-time, receive an Invoice Reference Number (IRN), and carry a QR code decodeable to invoice details verifiable on the GSTN portal.
For a covered retailer running RetailPOS, the integration is live before the first invoice goes out — no manual upload, no end-of- day batch, no spreadsheet workaround. This guide covers what GST e-invoicing actually requires, which businesses qualify (and the progressive threshold history that matters for current-year applicability), what the POS-to-IRP integration architecture looks like under the hood, the penalty schedule, the GSP (GST Suvidha Provider) and ASP (Application Service Provider) partner landscape, and how RetailPOS' e-invoicing connector ships.
The threshold timeline — and where it stands in 2026
GSTN's e-invoicing mandate rolled out in tranches:
- October 2020: ₹500 crore turnover threshold (large enterprises)
- January 2021: ₹100 crore
- April 2021: ₹50 crore
- April 2022: ₹20 crore
- October 2022: ₹10 crore
- August 2023: ₹5 crore
- Direction since: further reduction toward universal B2B coverage, with the threshold expected to drop further
The threshold check is based on annual aggregate turnover in any preceding financial year — meaning if your turnover crossed ₹5 crore in FY2022-23, e-invoicing applies to you in FY2026-27, even if subsequent years dropped below. Once you cross the threshold, you stay covered.
Track your trailing-12-month aggregate turnover continuously; the POS reporting tools surface this on a single dashboard view. The aggregate-turnover calculation includes all GSTINs registered under the same PAN — so a multi-branch retailer's combined turnover counts, not per-branch.
What GST e-invoicing actually requires
Every B2B invoice generated by your POS must:
- Be submitted to the IRP in real-time (within the allowed time window per current rules)
- Receive an Invoice Reference Number (IRN) — a 64-character hash uniquely identifying the invoice on GSTN
- Carry a QR code on the printed/PDF invoice that decodes to invoice details verifiable on the GSTN portal
- Include the buyer's GSTIN (mandatory for B2B; B2C invoices below threshold currently exempt)
- Include HSN/SAC codes for each line item, GST split (CGST/SGST/IGST/cess), reverse-charge applicability
- Be retained electronically for the audit retention period (currently 8 years)
The buyer-side experience: customers scanning the QR or entering the IRN on the GSTN portal verify the invoice was reported to GSTN. This eligibility check directly supports the buyer's input-tax credit claim — wrong or unreported invoices fail the buyer's GSTR-2A/2B match, breaking their tax credit. The real-time integration is the primary defence against input-credit mismatches.
For B2C invoices above ₹500 (currently the QR-only threshold for B2C), the QR code requirement applies without the full IRP submission. The POS handles both — full e-invoicing for B2B, B2C QR for above-threshold B2C invoices.
POS-to-IRP integration architecture
When a covered retailer rings a B2B sale on RetailPOS:
- Cashier rings the sale, captures buyer GSTIN (one-tap toggle on the till); standard checkout flow completes locally.
- On payment confirmation, the POS commits the sale locally + emits an outbox event for downstream consumers.
- The e-invoicing connector picks up the event; formats the invoice payload per GSTN's JSON schema; signs it with the registered API credentials.
- Connector posts to the IRP endpoint (one of multiple IRPs operating in parallel — NIC IRP, eInvoice1, eInvoice2 etc.); IRP responds with the IRN + signed QR-payload.
- Connector writes the IRN + QR back to the sale record; receipt printer prints the customer copy with IRN + QR.
Total elapsed time from payment confirmation to printed receipt: typically 1-4 seconds with healthy connectivity. The POS doesn't block on IRP response — if IRP is slow or briefly unreachable, the local sale completes on time and the connector retries in the background, then prints the IRN/QR on the digital receipt or via a customer-pickup reprint flow.
For sustained IRP outages (rare; the multi-IRP architecture provides redundancy), the connector queues invoices locally and submits in order when connectivity returns. GSTN policy permits a defined queuing window; the connector enforces that policy.
Registration + API credential provisioning
Registration flow:
- Log in to the GSTN e-Invoice portal with your GSTIN credentials
- Generate API credentials (client ID + client secret) for production use; sandbox credentials for testing
- Designate the GSP (GST Suvidha Provider) you'll route through, or use direct integration if eligible
- Configure the credentials into the POS during onboarding; the POS validates against the sandbox endpoint first
- Move to production endpoint after validation; first live B2B sale generates the first IRN
For multi-GSTIN retailers (one PAN, multiple state-level GSTINs for multi-state branches), each GSTIN has its own API credential set. RetailPOS' per-location GSTIN configuration handles this — the right credentials route based on which branch is generating the invoice.
For RetailPOS customers, the onboarding includes the GSTN credential setup; subsequent new branches self-serve via the back-office configuration screen.
Penalty schedule + audit-defensibility
GSTN penalty schedule for e-invoicing non-compliance:
- Issuing an invoice without obtaining IRN when required: ₹10,000 per invoice or 100% of tax involved, whichever is higher (Section 122).
- Issuing a non-compliant invoice (missing QR, wrong format): ₹25,000 per invoice (Section 122).
- Tax-credit denial to buyers if your invoice doesn't flow through IRP — operational impact on customer relationships (your B2B buyers can't claim ITC on your invoices, you lose them as customers).
- Late filing of GSTR-1 (consolidated monthly summary) due to e-invoicing data gaps: ₹50/day per delay (CGST + SGST = ₹100/day combined).
- Repeated non-compliance triggers GSTN audit escalation + GST registration suspension in extreme cases.
The tax-credit-denial-to-buyer impact is often more painful than the direct penalty — losing B2B customers because your invoices don't support their ITC claims compounds over time. The real-time IRP integration is the primary safeguard.
GSTN runs ITC mismatch reports comparing buyer-claimed ITC against seller-filed GSTR-1. Mismatches trigger demand notices to the buyer; the buyer escalates to the seller (you). E-invoicing prevents this by ensuring the seller's invoice flows into GSTN's system at issuance time.
GSP + ASP landscape — the integration partner ecosystem
GSTN's API access is mediated through GSPs (GST Suvidha Providers) — licensed companies authorised to provide API access to GSTN systems. There are 30+ licensed GSPs as of 2026; quality and ongoing service levels vary.
ASPs (Application Service Providers) are the broader category of companies building applications on top of GSP-provided API access; most POS vendors fall in the ASP category and route through one or more GSPs for the actual GSTN connectivity.
For a retailer running an international POS without native India e-invoicing support, the path is via an ASP + GSP combination — adds latency, a service fee per invoice, and additional integration failure points.
For a retailer running RetailPOS, the e-invoicing connector ships as part of the platform. We hold (or partner with the holding entity for) the licensed-GSP relationship; the connector is part of the standard sign-up flow for covered retailers; no separate ASP/GSP contract, no per-invoice fee beyond the platform subscription.
Reconciliation with GSTR-1 + GSTR-3B + GSTR-2A/2B
E-invoicing data auto-populates GSTR-1 (consolidated monthly outward supply return). When you (or your accountant) prepares GSTR-1 at month-end:
- GSTN's GSTR-1 auto-draft is pre-populated from your e-invoices submitted during the month
- You verify the auto-draft against your POS records; the POS exports the same period's sales as a CSV for manual cross-check
- Any non-e-invoiced transactions (B2C below the threshold, exempt supplies) add to the auto-draft manually
- File GSTR-1 by the 11th of the next month for monthly filers; quarterly for QRMP filers
GSTR-3B (the consolidated tax payment return) is filed by the 20th; GSTR-2A/2B (the auto-populated input-credit reconciliation) shows your buyers' invoices flowing in. The POS' reporting tools surface the data structured for each return type.
For GST audit visits, the data-export endpoint produces clean CSVs + per-invoice PDFs on demand. The full audit trail per invoice (POS-side sale record + GSTN-side IRN + the IRP interaction history with timestamps) gives you what you need to resolve any discrepancy quickly.
Frequently asked
- My turnover is currently ₹3.5 crore — does e-invoicing apply to me?
- Currently no, the threshold is ₹5 crore. But if your turnover crossed ₹5 crore in any preceding financial year (FY2020-21 onwards), e-invoicing applies regardless of current-year turnover. Check your historical turnover; once you cross the threshold, you stay covered.
- Does RetailPOS' e-invoicing integration cost extra?
- For standard retail categories, the connector ships as part of the platform — no separate per-invoice fee, no separate GSP/ASP integration fee. Specialised categories may have category-specific arrangements; confirm at sign-up.
- How long does API credential provisioning take?
- Typically 1-3 business days from GSTN e-Invoice portal application to credential issuance. RetailPOS' onboarding handles the technical steps; you provide the credential generation. Per-GSTIN setup for multi-state branches takes the same time per branch.
- What happens if the IRP is down during a sale?
- The local sale completes on time; the connector queues the submission and retries when the IRP recovers. GSTN policy permits a defined queueing window without penalty. The multi-IRP architecture (NIC + eInvoice1 + eInvoice2) provides redundancy; sustained outages are rare.
- Can I issue a B2B invoice without buyer GSTIN?
- If the buyer is a registered business (any B2B sale): GSTIN mandatory for e-invoicing eligibility. If buyer is unregistered (B2C): e-invoicing not required, but for invoices above ₹500 a QR code is required (handled automatically by the POS).
- Do I need a separate GSP relationship?
- For standard retail categories on RetailPOS — no. The platform holds (or partners with the holding entity for) the licensed-GSP status; the connector is native. For specialised categories or volume-tier requirements outside standard, confirm at sign-up.
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