Generate GST E-Invoice IRN JSON (NIC INV-01 Schema)

Skill: Convert invoice data into the IRP e-invoice JSON to obtain an IRN + signed QR

Region: India Category: E-Invoicing — GST e-invoicing Does: Takes ordinary B2B/export/SEZ invoice data and produces the NIC e-invoice JSON (the GST INV-01 schema) submitted to the Invoice Registration Portal (IRP), which returns a 64-character IRN (Invoice Reference Number), a digitally signed QR code, and an Ack No/Ack Date. Standard: GST e-invoice schema (Notification 60/2020-CT, GSTN/NIC INV-01)

E-invoicing is mandatory for registered taxpayers whose aggregate turnover crosses the notified threshold (currently ₹5 crore in any prior financial year) for B2B, exports, SEZ, and credit/debit notes — not for B2C. The IRP only registers the invoice and signs it; you still file GSTR-1 (e-invoices auto-populate it). Schema versions and master code lists change — always validate against the current GSTN/NIC INV-01 schema and the e-invoice sandbox before going live.

When this applies

• Supplier turnover over the notified threshold issuing B2B, SEZ, export, or deemed export invoices, plus credit notes (CRN) and debit notes (DBN).
• The IRN must be generated before the invoice is issued to the buyer; reporting must happen within 30 days of the invoice date for large taxpayers (AATO ≥ ₹10 crore).
• B2C invoices are out of scope (no IRN), though large taxpayers may need a self-generated dynamic QR.

Input data required

Document structure (INV-01 JSON)

{
  "Version": "1.1",
  "TranDtls":  { SupTyp, RegRev, IgstOnIntra },
  "DocDtls":   { Typ, No, Dt },
  "SellerDtls":{ Gstin, LglNm, Addr1, Loc, Pin, Stcd },
  "BuyerDtls": { Gstin, LglNm, Pos, Addr1, Loc, Pin, Stcd },
  "ItemList":  [ { SlNo, PrdDesc, IsServc, HsnCd, Qty, Unit, UnitPrice,
                   TotAmt, AssAmt, GstRt, IgstAmt, CgstAmt, SgstAmt, CesRt, CesAmt, TotItemVal } ],
  "ValDtls":   { AssVal, CgstVal, SgstVal, IgstVal, CesVal, RndOffAmt, TotInvVal }
}

Key rules: IsServc is Y for SAC (services) / N for HSN (goods). State code Stcd is the 2-digit GST state code (the same first two digits of the GSTIN). For intra-state supply, charge CgstAmt + SgstAmt; for inter-state supply (seller state ≠ POS), charge IgstAmt. Money fields are decimals; the IRP recomputes and rejects mismatches beyond the tolerance (±₹1 on item totals).

Calculation rules

• AssAmt (taxable value per line) = UnitPrice × Qty − discount.
• Intra-state: CgstAmt = SgstAmt = AssAmt × GstRt / 2. Inter-state: IgstAmt = AssAmt × GstRt.
• TotItemVal = AssAmt + CgstAmt + SgstAmt + IgstAmt + CesAmt.
• ValDtls totals = sum of the corresponding item fields; TotInvVal = AssVal + CgstVal + SgstVal + IgstVal + CesVal + RndOffAmt.
• The supply type (SupTyp) determines CGST/SGST vs IGST and whether export/SEZ "with payment" (WP) or "without payment" (WOP) of IGST applies.

Worked example (B2B intra-state, single line — request payload)

{
  "Version": "1.1",
  "TranDtls": { "TaxSch": "GST", "SupTyp": "B2B", "RegRev": "N", "IgstOnIntra": "N" },
  "DocDtls": { "Typ": "INV", "No": "INV-2025-0042", "Dt": "04/06/2025" },
  "SellerDtls": {
    "Gstin": "29AABCU9603R1ZM", "LglNm": "Acme Components Pvt Ltd",
    "Addr1": "12 Industrial Layout", "Loc": "Bengaluru", "Pin": 560058, "Stcd": "29"
  },
  "BuyerDtls": {
    "Gstin": "29AAACR5055K1Z5", "LglNm": "Nilgiri Traders",
    "Pos": "29", "Addr1": "5 MG Road", "Loc": "Bengaluru", "Pin": 560001, "Stcd": "29"
  },
  "ItemList": [
    {
      "SlNo": "1", "PrdDesc": "Steel bracket", "IsServc": "N", "HsnCd": "73269099",
      "Qty": 100, "Unit": "NOS", "UnitPrice": 150.00,
      "TotAmt": 15000.00, "AssAmt": 15000.00,
      "GstRt": 18.0, "IgstAmt": 0.00, "CgstAmt": 1350.00, "SgstAmt": 1350.00,
      "CesRt": 0, "CesAmt": 0.00, "TotItemVal": 17700.00
    }
  ],
  "ValDtls": {
    "AssVal": 15000.00, "CgstVal": 1350.00, "SgstVal": 1350.00,
    "IgstVal": 0.00, "CesVal": 0.00, "RndOffAmt": 0.00, "TotInvVal": 17700.00
  }
}

The IRP responds with the registration result — the IRN, signed invoice (JWT), and signed QR:

{
  "AckNo": 112010033456789,
  "AckDt": "2025-06-04 11:32:00",
  "Irn": "a1b2c3d4e5f60718293a4b5c6d7e8f90112233445566778899aabbccddeeff00",
  "SignedInvoice": "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9...",
  "SignedQRCode": "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9...",
  "Status": "ACT"
}

Print the IRN and embed the SignedQRCode on the physical/PDF invoice.

Validation checklist

• Current GSTN/NIC INV-01 schema version (Version) and master code lists used
• SupTyp matches the transaction (B2B / SEZWP / SEZWOP / EXPWP / EXPWOP / DEXP)
• Valid 15-char GSTINs; Stcd = first two digits of the GSTIN; POS set for the buyer
• Each line has HSN/SAC, IsServc flag, UQC unit, GstRt, and tax amounts
• Intra-state → CGST+SGST; inter-state (seller state ≠ POS) → IGST only
• TotItemVal and ValDtls totals reconcile; TotInvVal = assessable + taxes + round-off
• Reported within the 30-day window (AATO ≥ ₹10 cr); IRN generated before issuing the invoice
• IRN + signed QR placed on the issued invoice; e-invoices reconciled into GSTR-1

Last updated: 2026-06-04 — confirm the active schema version, field codes, and portal/API requirements against the current GSTN / NIC (einvoice1.gst.gov.in) specifications before use.