Your accountant says your invoice needs an IRN. Your customer is asking why their GSTR-2B does not show your invoice. Your warehouse team is holding a consignment because someone said you need to register the invoice first. And you are looking at a 64-character alphanumeric string on your screen wondering what it actually is and why the government needs it.
If any of this resonates — this guide is written specifically for you.
The IRN — Invoice Reference Number — is the heart of India's e-invoicing system. Every business above the ₹5 crore GST turnover threshold must obtain an IRN for every B2B invoice before supplies are made. The process of generating this IRN — how it works, why it exists, what happens technically, and what it means for your business operations — is something every Indian business owner, accountant, and compliance manager needs to understand clearly in 2026.
This comprehensive guide explains the entire IRN generation process from start to finish — in plain language, with complete technical detail where needed, covering every aspect from what IRN actually is to how the generation works step by step, what happens to your invoice and your GST compliance after IRN is generated, common IRN errors and how to resolve them, and how ERP Group's accounting software makes IRN generation completely automatic — so you understand the process without having to manually execute it every time.
What is IRN? — A Complete Explanation for Indian Business Owners
IRN in Plain Language
IRN stands for Invoice Reference Number. It is a unique identification number assigned by India's government to every B2B invoice that is registered with the Invoice Registration Portal (IRP) under the e-invoicing mandate.
Think of IRN as the government's official stamp on your invoice — confirming that this specific invoice, between this specific supplier and this specific buyer, for this specific transaction, has been officially recorded in India's national GST database. Without this stamp, your invoice exists only in your records and your buyer's records — but not in the government's system.
What IRN Looks Like
An IRN is a 64-character alphanumeric string — a combination of numbers and letters. Here is what an example IRN looks like:
a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2
This 64-character string is actually a hash value — generated by applying a mathematical hashing algorithm to a specific combination of your invoice's identifying information. This means the IRN is not randomly assigned — it is mathematically derived from your invoice data in a way that makes it unique, verifiable, and tamper-evident.
The Three Pieces of Information That Generate the IRN Hash
The IRN is generated by applying the SHA-256 hashing algorithm to a concatenation of three specific pieces of information from your invoice:
Component 1 — Seller's GSTIN
Your 15-digit GSTIN — the unique identifier of the business generating the invoice.
Component 2 — Financial Year
The financial year in which the invoice is issued — in the format YYYY-YY (for example, 2025-26).
Component 3 — Invoice Number
Your invoice number exactly as entered — including any prefix, suffix, or series identifier.
The SHA-256 hash of these three concatenated values produces the 64-character IRN. This means every invoice from your business in a given financial year will have a unique IRN — because the invoice number changes for each invoice. And no two businesses will ever have the same IRN for the same invoice number — because your GSTIN is unique.
What IRN is NOT
IRN is not a tax payment confirmation. It is not an invoice approval by the government. It is not a quality or authenticity certification beyond GST compliance. It is not a replacement for your invoice number — your original invoice number remains the primary reference for your business records. IRN is specifically and only the government's registration reference for your invoice in the national GST database.
Why Does India's GST System Require IRN?
The Problem IRN Solves — Fake Invoice Fraud
Before e-invoicing and IRN were introduced, India's GST system had a significant fraud problem. Businesses were creating fictitious invoices — invoices that looked legitimate but represented transactions that never actually occurred — to fraudulently claim Input Tax Credit. A business could create a fake invoice from a non-existent or complicit supplier, claim ITC based on the fake invoice, and reduce their actual tax liability.
This fake invoice fraud cost India's exchequer thousands of crores every year and undermined the integrity of the entire GST system.
How IRN Eliminates Fake Invoice Fraud
IRN eliminates fake invoice fraud through a simple but powerful mechanism. Every B2B invoice must be registered with the government's IRP before the supply occurs. The IRP verifies that the seller's GSTIN is active and the buyer's GSTIN is active. When both GSTINs are verified, the invoice is registered and an IRN is assigned.
The buyer can only claim ITC against invoices that appear in their GSTR-2B — and GSTR-2B is populated automatically from IRP-registered invoices. If an invoice does not have an IRN registered on the IRP, it does not appear in the buyer's GSTR-2B, and no ITC can be claimed.
A fake invoice from a fake supplier cannot get an IRN — because the fake supplier's GSTIN either does not exist or is inactive. Without an IRN, the fake invoice cannot generate ITC. Fake invoice fraud is structurally eliminated.
Secondary Benefits of the IRN System
Beyond fraud prevention, the IRN system delivers significant secondary benefits for India's tax administration. Real-time transaction visibility gives the government a live view of the country's commercial activity — enabling better tax forecasting, economic analysis, and compliance monitoring. Automatic GSTR-1 population from IRP data reduces data entry errors and return filing discrepancies. Cross-referencing between supplier GSTR-1 and buyer GSTR-2B happens automatically — eliminating the manual reconciliation burden that previously generated significant compliance disputes.
Who Must Generate IRN in India in 2026?
The Mandatory Threshold
IRN generation through e-invoicing is mandatory for all GST-registered businesses with annual aggregate turnover exceeding ₹5 crore in any preceding financial year. This aggregate turnover is calculated across all GSTINs registered under the same PAN — not just a single GSTIN.
Which Documents Require IRN?
Not every document your business issues requires IRN generation — even if you are above the threshold:
Documents That MUST Have IRN
Tax invoices for all B2B supplies to registered buyers. Tax invoices for all exports including zero-rated supplies under LUT. Tax invoices for supplies to SEZ units and developers. Debit notes issued against previously IRN-registered invoices. Credit notes issued against previously IRN-registered invoices.
Documents That Do NOT Require IRN
Tax invoices for B2C supplies to unregistered customers. Bill of supply for exempt or nil-rated goods and services. Delivery challans for job work or goods movement without supply. Advance payment receipts. Import invoices (generated by foreign suppliers outside India's GST system). Invoices issued by Input Service Distributors (ISD).
The Progressive Threshold History
The government introduced e-invoicing for businesses above ₹500 crore in October 2020 and has progressively reduced the threshold — to ₹100 crore, ₹50 crore, ₹20 crore, ₹10 crore, and ₹5 crore. The clear direction of this progression indicates that eventually all GST-registered businesses will be required to generate IRN for B2B invoices. Businesses approaching ₹5 crore should implement IRN generation capability now.
The IRN Generation Process — Complete Step-by-Step Explanation
Overview of the IRN Generation Workflow
The IRN generation process involves six distinct stages — from invoice creation to government registration to the return of IRN to the supplier. Understanding each stage helps you appreciate both what the process requires and what automatic e-invoice software is doing on your behalf.
Stage 1 — Invoice Creation and Data Preparation
What Happens at This Stage
You create your sales invoice — entering all required information including your supplier details (GSTIN, name, address), buyer details (GSTIN, name, address), invoice number, invoice date, supply type, line items with HSN codes, quantities, unit prices, taxable values, and applicable tax amounts.
Critical Data Requirements for IRN Generation
Every field that the IRP requires must be correctly populated — not just the fields that appear on your standard invoice. The IRP requires data in a specific schema with specific field codes and formats. For example, the unit of measurement must use the government's approved UQC (Unit Quantity Code) — not free text. The place of supply must use the state code format. The supply type must use specific codes (B2B, EXPWOP, EXPWP, SEZWOP, SEZWP, DEXP).
Manual data preparation that correctly maps all your invoice information to the IRP's required schema is complex and error-prone. Automatic e-invoice software handles this mapping automatically — you enter standard invoice information and the software generates the correctly structured IRP schema.
GSTIN Verification at This Stage
Before proceeding, the buyer's GSTIN must be verified as active. An invoice with an inactive or invalid buyer GSTIN will fail IRP validation — wasting all subsequent effort. The best practice is to verify GSTINs at customer creation — not at invoice time. ERP Group's accounting software validates GSTINs against the live GSTN database at the moment a customer record is created — ensuring invalid GSTINs never reach the IRP.
Stage 2 — JSON Schema Generation
What is JSON and Why Does the IRP Require It?
JSON (JavaScript Object Notation) is a standardised data format used for transmitting structured data between computer systems. The IRP requires invoice data to be submitted in a specific JSON schema — a precisely defined format with specific field names, data types, and structure.
The IRP JSON Schema Structure
The IRP's JSON schema for e-invoices has multiple sections:
Version — The schema version number (currently Version 1.1 as of 2026).
TranDtls (Transaction Details) — Tax scheme (GST), supply type code (B2B/EXPWOP/etc.), e-commerce operator GSTIN if applicable.
DocDtls (Document Details) — Document type (INV/CRN/DBN), document number, document date.
SellerDtls (Seller Details) — Seller GSTIN, legal name, trade name, address, PIN, state code, phone, email.
BuyerDtls (Buyer Details) — Buyer GSTIN, legal name, trade name, address, PIN, state code, place of supply, phone, email.
DispDtls (Dispatch From Details) — Name, address, city, PIN, state code of the actual dispatch location if different from seller's registered address.
ShipDtls (Ship To Details) — Name, address, city, PIN, state code of the actual delivery location if different from buyer's registered address.
ItemList (Item Details) — Array of line items, each containing: serial number, HSN/SAC code, product description, UQC code, quantity, unit price, gross amount, discount, taxable value, GST rate, IGST/CGST/SGST amounts, cess rate and amount, total item value.
ValDtls (Value Details) — Total assessable value, total IGST, total CGST, total SGST, total cess, round-off, total invoice value.
EwbDtls (E-Way Bill Details) — Transport mode, distance, transporter ID, transporter name, transporter document number, vehicle number — required only when requesting simultaneous e-way bill generation.
Why Manual JSON Generation is Not Practical
Correctly formatting a multi-line invoice into this JSON schema — with all required field names, data types, and structure — requires programming knowledge that is beyond most accounting staff. This is why automatic e-invoice software is essential — it generates the correct JSON automatically from your standard invoice data.
Stage 3 — IRP API Submission
What is an API?
API stands for Application Programming Interface — a technical connection between two software systems that allows them to exchange data directly. Instead of a human logging into the IRP portal and filling forms, the software sends the invoice JSON directly to the IRP's computer systems through this API connection.
Authentication for IRP API Access
Before the JSON can be submitted, the software must authenticate with the IRP — proving it has authorisation to submit invoices on behalf of your GSTIN. Authentication uses your GSTIN credentials combined with application-level credentials that the software vendor obtains through GSTN's authorisation process.
Software vendors offering IRP API integration must be officially registered and certified by GSTN/NIC as authorised API service providers. Only certified providers are allowed to make API calls to the IRP on behalf of taxpayers. This certification is the key differentiator between genuine automatic e-invoice software and untested or unofficial tools.
The API Call
The authenticated API call transmits your invoice JSON to the IRP server. This transmission happens over an encrypted HTTPS connection — ensuring the invoice data cannot be intercepted or modified in transit. The entire transmission completes in milliseconds — the primary delay in IRN generation comes from IRP processing time, not data transmission.
Stage 4 — IRP Validation
What the IRP Validates
When the IRP receives your invoice JSON, it performs a comprehensive series of validation checks before generating the IRN:
GSTIN Validation — The seller's GSTIN is verified as registered and active in the GSTN database. The buyer's GSTIN is verified as registered and active. For export invoices, the relevant party identifiers are verified as appropriate.
Schema Validation — The JSON structure is verified to conform to the IRP's required schema — all mandatory fields present, data types correct, field values within permitted ranges.
HSN Code Validation — Every HSN or SAC code in the invoice is verified against the current GSTN HSN master — confirming it is a valid code at the correct digit level for the supplier's turnover category.
GST Rate Validation — The GST rate applied to each line item is verified against the applicable rate for the HSN code — confirming the correct rate is being charged.
Mathematical Validation — Tax amounts are recalculated and compared to the values in the JSON — verifying that CGST, SGST, and IGST amounts are mathematically correct based on taxable values and applicable rates.
UQC Validation — Every unit of measurement code is verified against the IRP's approved UQC list.
Invoice Number Uniqueness — The combination of supplier GSTIN, financial year, document type, and document number is verified to be unique — no previously registered invoice with the same combination can exist.
Date Validation — The invoice date is verified to be a valid date within the current financial year and not a future date.
What Happens if Validation Fails
If any validation check fails, the IRP immediately returns an error response containing specific error codes and descriptions — indicating exactly which field failed and why. No IRN is generated. The JSON must be corrected and resubmitted.
Common error codes include 2150 for invalid buyer GSTIN, 2230 for duplicate invoice number, 2271 for tax amount mismatch, 2283 for invalid HSN code, 2275 for invalid UQC, and 2246 for future invoice date.
What Happens When All Validations Pass
When every validation check passes, the IRP proceeds to IRN generation — typically within 1-3 seconds of receiving the JSON.
Stage 5 — IRN Generation and Digital Signing
The IRN Hash Generation
The IRP generates the 64-character IRN by applying the SHA-256 (Secure Hash Algorithm 256-bit) hashing function to the concatenation of three values — the supplier's GSTIN, the financial year (YYYY-YY format), and the invoice document number.
SHA-256 is a one-way mathematical function — given the same input, it always produces the same output, but you cannot reverse the output to determine the input. This means the IRN is deterministic — the same invoice from the same supplier in the same financial year will always produce the same IRN — and verifiable — anyone with the three input values can independently verify whether a given IRN is correct.
Digital Signing of the Invoice
After generating the IRN, the IRP digitally signs the complete invoice JSON using the government's digital signature — creating a cryptographically verified record that cannot be altered without detection. This digital signature is what makes the e-invoice legally authentic — it proves the invoice was registered with the government at a specific time and that the data has not been modified since registration.
QR Code Generation
The IRP generates a QR code that encodes the key invoice parameters — supplier GSTIN, buyer GSTIN, invoice number, invoice date, invoice value, number of line items, HSN of the main line item, IRN, and IRP signing timestamp. This QR code is embedded in the invoice document and allows anyone with the GSTN verification app to instantly verify the invoice's authenticity by scanning the code.
Stage 6 — IRP Response Return
What the IRP Returns
After successful IRN generation and digital signing, the IRP returns a response containing the complete registered invoice data including the IRN, the digitally signed invoice JSON, the QR code, the acknowledgement number (a sequential IRP transaction reference), and the acknowledgement date and time.
Response Processing by Your Software
Your accounting software receives the IRP response and processes it — extracting the IRN and QR code, updating your invoice record with these details, triggering the buyer notification, and storing the signed JSON in the compliance archive.
For businesses using manual portal e-invoicing, this step requires manually noting the IRN, downloading the QR code, and updating the invoice — adding several minutes to the process for every invoice. For businesses using ERP Group's automatic e-invoice software, this entire response processing happens programmatically within milliseconds — the invoice is updated with IRN and QR code before you can blink.
What Happens After IRN is Generated — The Downstream Effects
Your Invoice Becomes a Legally Valid E-Invoice
Once your invoice has an IRP-assigned IRN and the QR code is embedded, it is a legally valid e-invoice under India's GST law. For businesses above the e-invoicing threshold, only IRN-stamped invoices are valid B2B invoices. Invoices without IRN — however professionally designed — are non-compliant for qualifying transactions.
Automatic GSTR-1 Population
Within a short period of IRN generation, the IRP sends your invoice data to the GSTN portal — which automatically populates your GSTR-1 outward supply return with the invoice details. The invoice appears in the correct GSTR-1 table based on its supply type — Table 4A for regular B2B, Table 6A for exports, etc.
This automatic population means that every e-invoiced transaction is already in your GSTR-1 without any separate data entry. When you file GSTR-1, your e-invoice data is pre-populated — you only need to add any non-e-invoiced transactions (B2C summary, etc.) before filing.
For a complete understanding of how e-invoice data interacts with GSTR-1 and common errors that can arise, read our detailed guide on GSTR-1 filing errors and how to fix them.
Buyer's GSTR-2B is Updated
The IRP simultaneously sends your invoice data to the buyer's GSTN profile — where it appears in their GSTR-2B auto-populated ITC statement. Your buyer can see the confirmed ITC available from your invoice in real time — without waiting for your monthly GSTR-1 filing.
This real-time ITC confirmation is a significant benefit for your business relationships — your buyers receive payment-ready ITC confirmation immediately after you generate the e-invoice, rather than having to wait up to 45 days for your GSTR-1 filing to reflect in their GSTR-2B.
E-Way Bill Status Confirmation
If you requested simultaneous e-way bill generation — and the IRP confirmed it — the e-way bill is live in the NIC e-way bill system from the moment of IRN generation. Your transporter can begin the journey with valid documentation immediately.
ERP Group's warehouse management system receives the e-way bill number alongside the IRN automatically — updating the dispatch record and making complete documentation immediately available for the transport team.
IRN Structure and Format — Complete Technical Breakdown
Understanding the 64-Character IRN
The SHA-256 Algorithm
SHA-256 is a cryptographic hash function that takes any input of any length and produces a fixed-length 256-bit (32-byte) output. When expressed as a hexadecimal string (using characters 0-9 and a-f), this 256-bit output becomes a 64-character string — which is the IRN.
Why SHA-256 Makes IRN Reliable
SHA-256 has two critical properties that make it ideal for IRN generation. First — deterministic: the same GSTIN, financial year, and invoice number will always produce the same IRN. This means the IRN can be independently verified by anyone who has the three input values. Second — collision-resistant: it is computationally impossible to find two different inputs that produce the same output. This means no two genuinely different invoices from different suppliers or with different numbers will ever share the same IRN.
What the IRN Looks Like in Practice
The 64 hexadecimal characters appear as a continuous string — lower case letters a through f and digits 0 through 9, with no spaces, hyphens, or separators. Every valid IRN is exactly 64 characters long — no more, no less. Any IRN that is shorter or longer than 64 characters is invalid.
The Acknowledgement Number — Different From IRN
The IRP returns both an IRN and an Acknowledgement Number alongside it — and these are not the same thing. The IRN is the mathematical hash of your invoice identifying data — unique to that specific invoice. The Acknowledgement Number is the IRP's sequential transaction reference — a sequential number assigned by the IRP to each successful registration in order of processing. The Acknowledgement Number combined with the Acknowledgement Date and Time is your proof that the IRP processed your submission at a specific moment.
Both the IRN and the Acknowledgement Number should be stored in your compliance records — the IRN is your primary invoice identifier in the GST system, while the Acknowledgement Number is your evidence of registration timing.
The QR Code — What It Contains and How It Works
QR Code Content
The QR code embedded in every e-invoice encodes the following information — supplier GSTIN, buyer GSTIN, invoice number, invoice date, invoice value (total including GST), number of line items in the invoice, HSN code of the primary line item (the item with the highest value), the full IRN, the IRP digital signature, and the IRP acknowledgement timestamp.
How to Verify a QR Code
The government's GSTN verification app — available on iOS and Android — allows anyone to scan the QR code on an e-invoice and instantly verify its authenticity. The app reads the QR code data, independently calculates the expected IRN from the supplier GSTIN, financial year, and invoice number, and compares it to the IRN in the QR code. A match confirms the invoice is genuine. A mismatch indicates potential fraud or data tampering.
Why QR Code Verification Matters for Your Business
Your buyers, auditors, and bank lenders can verify your e-invoices instantly using the QR code — without logging into any portal. For businesses seeking invoice financing or supply chain credit, QR code-verified e-invoices provide instant authentication that accelerates approval processes.
IRN Cancellation Process — When and How to Cancel an IRN
When Can an IRN Be Cancelled?
An IRN can be cancelled on the IRP only within 24 hours of the acknowledgement timestamp recorded when the IRN was generated. After this 24-hour window, the IRN remains permanently in the GSTN system and cannot be cancelled — even if the underlying transaction was cancelled.
The 24-hour window also has an additional condition — the IRN can only be cancelled if no e-way bill has been generated against it, or if the e-way bill associated with it has also been cancelled. Active e-way bills block IRN cancellation.
Valid Reasons for IRN Cancellation
The IRP accepts the following cancellation reason codes — Reason Code 1 (Duplicate), Reason Code 2 (Data Entry Mistake), Reason Code 3 (Order Cancelled), and Reason Code 4 (Other reasons with mandatory explanation).
The IRN Cancellation Process
Step 1 — Navigate to Cancel IRN on IRP
Log into the IRP portal and navigate to E-Invoice → Cancel IRN. Or through your accounting software if it supports IRN cancellation via API — which ERP Group does.
Step 2 — Enter the IRN
Enter the 64-character IRN of the invoice to be cancelled. Click Get Details. The IRP displays the registered invoice information — verify this is the correct invoice.
Step 3 — Select Reason and Confirm
Select the cancellation reason code and enter any required explanation. Check the confirmation checkbox and click Cancel IRN.
Step 4 — Receive Cancellation Confirmation
The IRP confirms successful cancellation. The invoice is marked as cancelled in the GSTN system and removed from the buyer's GSTR-2B. Your GSTR-1 auto-population for this invoice is also reversed.
After the 24-Hour Window — Credit Note Approach
If the 24-hour cancellation window has passed, the standard remedy is to issue a credit note against the original invoice. The credit note must also be e-invoiced — registered on the IRP as document type CRN — with the original invoice number referenced. This credit note approach effectively reverses the supply in the GST system while preserving the original IRN in the historical record.
ERP Group handles both within-window IRN cancellation (directly through IRP API) and post-window credit note e-invoicing (automatically registering the credit note on the IRP as document type CRN).
IRN for Credit Notes and Debit Notes
Do Credit Notes and Debit Notes Need IRN?
Yes — credit notes and debit notes issued against B2B invoices that were originally e-invoiced also require IRN generation. The credit note or debit note must be registered on the IRP just like a tax invoice — with document type CRN for credit note and DBN for debit note.
Specific Requirements for Credit Note and Debit Note IRN
Original Invoice Reference Mandatory
Credit note and debit note IRP submissions must include the original invoice number and original invoice date — establishing the link between the adjustment document and the original supply. Without this reference, the IRP cannot properly update the buyer's GSTR-2B ITC position.
IRN Generation Process for Credit Notes
The IRN generation process for credit notes follows the same six stages as for tax invoices — with the document type set to CRN and the original invoice details included in the JSON. The IRP validates the credit note data including the original invoice reference and generates a separate IRN for the credit note — distinct from the original invoice IRN.
Impact on GSTR-2B
When your credit note IRN is generated and the IRP data flows to GSTN, the buyer's GSTR-2B is updated to show the credit note — reducing the available ITC from the original invoice by the credit note amount. This automatic GSTR-2B update is why credit note e-invoicing compliance matters — your buyers need their GSTR-2B to accurately reflect net ITC after returns and revisions.
Common IRN Generation Errors — Causes and Complete Solutions
Error 2150 — Supplier/Recipient GSTIN Invalid or Inactive
Cause
The buyer's GSTIN entered in the invoice is not registered, has been cancelled, is suspended, or contains a data entry error.
Solution
Verify the GSTIN at search.gst.gov.in. If the GSTIN is genuinely inactive — contact your buyer for their current active GSTIN before proceeding. If the GSTIN has a data entry error — correct it and resubmit.
Prevention
ERP Group validates every GSTIN at customer record creation — making this error structurally impossible for invoices created through the software.
Error 2230 — Duplicate IRN (Invoice Already Registered)
Cause
An invoice with the same GSTIN + financial year + document type + document number combination has already been registered on the IRP. The IRN for this combination already exists.
Solution
Use the IRP's IRN search to retrieve the existing registration details. If the previously registered invoice is correct — use the existing IRN. If it contains errors — cancel within 24 hours and re-register with a new invoice number.
Understanding Why Duplicate IRN is Impossible for Genuine Invoices
Since IRN is a mathematical hash of GSTIN + financial year + invoice number — any genuinely unique invoice number will always produce a unique IRN. A duplicate IRN error means the same invoice number has been submitted twice — indicating either a double-submission by the software or incorrect invoice numbering.
Error 2271 — Tax Amount Mismatch
Cause
The CGST, SGST, or IGST amounts in the invoice JSON do not match the calculated values based on the entered taxable values and GST rates.
Solution
Recalculate all tax amounts from first principles — taxable value multiplied by applicable rate divided by 100. For CGST and SGST on an 18% GST item, each is 9% of taxable value. Correct and resubmit.
Prevention
ERP Group calculates all tax amounts automatically from taxable values and rates — making mathematical tax errors impossible.
Error 2283 — HSN/SAC Code Not Found
Cause
The HSN code entered for a line item is not in the current GSTN HSN master — either because it is genuinely invalid, at the wrong digit level for the taxpayer's turnover, or because it is an outdated code that has been replaced in a recent HSN revision.
Solution
Verify the correct HSN code on the CBIC website's HSN search. Confirm the correct digit level requirement for your annual turnover. Update your product master and resubmit.
Prevention
ERP Group's complete, auto-updated HSN database ensures every product has a current, valid HSN code — eliminating this error category.
Error 2275 — Invalid UQC (Unit Quantity Code)
Cause
The unit of measurement entered for a line item is not from the IRP's approved UQC list — typically caused by entering free text (like "PCS", "KG", or "MTR") instead of selecting from the approved codes (NOS, KGS, MTR).
Solution
Replace the free-text UQC with the correct approved code from the IRP's UQC master list. Common approved codes include NOS (Numbers), KGS (Kilograms), MTR (Metres), LTR (Litres), SQM (Square Metres), CBM (Cubic Metres), and dozens of others.
Prevention
ERP Group's product master includes a complete UQC dropdown — ensuring only valid approved codes are ever assigned to products.
Error 2246 — Invoice Date Greater Than Current Date
Cause
The invoice date entered is a future date. The IRP does not accept invoices dated after the current system date.
Solution
Correct the invoice date to today's date or a past date within the current financial year.
Error 2152 — Distance Invalid for E-Way Bill
Cause
When requesting simultaneous e-way bill generation, the distance entered is zero, negative, or unrealistically large.
Solution
Enter a realistic distance in kilometres between dispatch and delivery locations. The e-way bill validity period is calculated from this distance — so accuracy matters for transport compliance.
IRP Timeout or Service Unavailable
Cause
The IRP portal is experiencing high traffic or technical difficulties — returning a timeout error or service unavailable response.
Solution
For manual portal users — wait and retry after a few minutes or switch to an alternate IRP. For ERP Group users — the software automatically retries and routes to alternate IRPs without any manual action.
👉 For understanding how IRN errors relate to broader GSTR-1 filing issues, read our complete guide on GSTR-1 filing errors and how to fix them.
How ERP Group Automates the Entire IRN Generation Process
ERP Group's IRN Generation Architecture
ERP Group's accounting software has direct, certified API integration with all five government-designated IRPs — with a multi-layer automation architecture that handles every stage of the IRN generation process automatically.
Customer GSTIN Validated at Creation
When you create a customer record in ERP Group, the GSTIN is automatically validated against the live GSTN database. Invalid or inactive GSTINs are flagged immediately — before any invoice is created. This prevents GSTIN-related IRP failures entirely.
Invoice Creation Triggers Automatic JSON Generation
When you create a B2B invoice in ERP Group, the software automatically generates the complete IRP JSON payload — mapping every invoice field to the correct schema element, applying correct supply type codes, UQC codes, and all IRP-specific data requirements. No separate JSON preparation is required.
Real-Time IRP API Submission
The JSON is submitted to the IRP through a secure API connection simultaneously with invoice saving — in real time. The software awaits the IRP response before completing the invoice creation workflow.
Automatic Multi-IRP Failover
ERP Group monitors all five IRP portals continuously. Primary submission is to NIC. If NIC returns an error or timeout, the software automatically resubmits to the next available IRP — without any delay visible to your team. Your invoice gets an IRN regardless of which specific IRP processes it.
Automatic Invoice Update With IRN and QR Code
The IRP response is processed automatically — the IRN and QR code are extracted and immediately embedded in the invoice record. The invoice is updated to show the IRN prominently and the QR code in the prescribed position — compliant with GSTN's e-invoice display guidelines.
Simultaneous E-Way Bill Generation
For qualifying goods invoices, ERP Group requests e-way bill generation in the same IRP API call — receiving both IRN and e-way bill number in the same response. ERP Group's warehouse management system receives both numbers automatically, updating dispatch documentation without any separate action.
WhatsApp and Email Delivery
The IRN-stamped e-invoice is automatically sent to the buyer via WhatsApp and email immediately after IRN generation — with no manual forwarding step.
GSTR-1 Auto-Population
Every IRN-registered invoice automatically contributes to your GSTR-1 data — so by filing day, all e-invoiced transactions are already in your return without any data entry.
Complete Business Integration for End-to-End IRN Compliance
ERP Group's IRN generation capability is embedded across the entire platform. B2B sales from POS software automatically trigger IRN generation for registered customers. Goods dispatches from warehouse management automatically trigger IRN and e-way bill generation. Service invoices from CRM software automatically determine correct place of supply and trigger IRN for registered clients. HR & Payroll software manages employee compliance completely separately — maintaining clean data integrity across the platform.
👉 For the complete step-by-step portal process that ERP Group automates on your behalf, read our detailed guide on how to generate e-invoice on GST portal step by step.
👉 For small business owners new to e-invoicing, read our complete guide on e-invoice generation for small business India.
👉 For a comparison of automatic e-invoice generation software options in India, read our guide on automatic e-invoice generation software India.
IRN Generation for Specific Business Scenarios
IRN for Multi-GSTIN Businesses
Businesses with multiple GSTINs — one for each state of operations — must generate IRN from the specific GSTIN under which the invoice is raised. Each GSTIN has its own invoice number series, its own IRP credentials, and its own IRN history. ERP Group supports multi-GSTIN configurations — maintaining separate invoice series, separate IRP credential sets, and separate compliance records for each GSTIN while providing consolidated reporting across all GSTINs from a single login.
IRN for Export Invoices
Export invoices require IRN just like domestic B2B invoices — with supply type code EXPWOP (export without IGST payment under LUT) or EXPWP (export with IGST payment). Export e-invoices include additional fields — shipping bill number (if available at invoice time) and port code. ERP Group's export invoice workflow includes these additional fields and automatically sets the correct supply type code based on whether a LUT reference is configured in the business profile.
IRN for High-Frequency Trading Businesses
Trading businesses generating hundreds of B2B invoices daily cannot afford any per-invoice manual steps. ERP Group's asynchronous processing capability handles high-frequency invoice creation — queuing IRP submissions during peak creation periods and processing them in rapid sequence with automatic priority management. Even during high-volume periods, IRN generation completes within seconds of invoice creation.
Conclusion — Understanding IRN is the Foundation of E-Invoice Compliance
The IRN generation process — from invoice creation through JSON schema generation, IRP API submission, validation, SHA-256 hash generation, digital signing, and response processing — is the technical foundation of India's entire e-invoicing compliance system. Understanding this process gives you clarity on what your compliance requirement actually involves, why each step exists, and what good e-invoice software is doing on your behalf when it generates IRN automatically.
For businesses above the ₹5 crore threshold in India, IRN generation for every qualifying B2B invoice is not optional — it is a legal requirement with significant penalties for non-compliance and real financial consequences for your buyers when compliance gaps occur.
ERP Group's accounting software handles the entire IRN generation process — from GSTIN validation at customer creation through multi-IRP API submission, error-free JSON generation, automatic invoice update, WhatsApp and email buyer delivery, and complete compliance archiving — automatically, in seconds, for every qualifying invoice. Combined with warehouse management for simultaneous e-way bill generation, POS software for retail B2B invoicing, CRM software for service invoice management, and HR & Payroll for complete business compliance — ERP Group gives Indian businesses a platform where IRN compliance is invisible, automatic, and never a barrier to operations.
Understand the IRN process. Then let ERP Group handle it automatically — every invoice, every time, in seconds.
Join 5,000+ Indian businesses generating IRN-compliant e-invoices automatically with ERP Group.
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