To generate an e-invoice under India’s GST system, you upload your invoice data in JSON format to the government’s Invoice Registration Portal (IRP), which validates the entries and returns a unique Invoice Reference Number (IRN), a digitally signed invoice, and a QR code. Once you know what the portal expects and how the validation works, the process is quick. Most rejections come down to a handful of predictable mistakes in tax type, HSN codes, or totals.
Who Must Generate E-Invoices
E-invoicing is mandatory under Rule 48(4) of the CGST Rules for notified classes of registered persons.1CBIC Tax Information. CGST Rule 48 The current threshold is an aggregate annual turnover of ₹5 crore or more in any financial year from 2017–18 onward, calculated on a PAN basis rather than per-GSTIN.2Goods and Services Tax Network. E-Invoicing FAQs It applies to B2B supplies, exports, and business-to-government transactions. If your turnover crossed ₹5 crore even once since 2017–18, you remain covered in future years even if revenue later drops below that level.
Businesses with turnover between ₹5 crore and ₹10 crore that have not been automatically enabled can opt in through the Registration menu on the e-invoice portal.3e-Invoice System. e-Invoice System
Some categories are exempt even when they cross the turnover threshold: banks, insurance companies, and NBFCs; goods transport agencies; passenger transport services; suppliers of cinema admission services; and SEZ units (though SEZ developers are not exempt).4e-Invoice System. E-Invoicing Changes, Exemptions, Documents, Transactions Covered B2C invoices are outside the mandate entirely.
What Data You Need Ready
The e-invoice JSON schema has roughly 30 mandatory fields. Getting them right before you upload avoids repeated validation failures.
Supplier and Buyer Details
Both parties’ 15-digit GSTINs, legal names, and full addresses including street, city, state code, and six-digit pin code. The place of supply state code decides whether the transaction is interstate or intrastate, which controls whether the portal expects IGST or a CGST/SGST split. A wrong state code is one of the fastest paths to a rejection.
Item-Level Details
Every line needs an HSN code for goods or SAC for services. Taxpayers above ₹5 crore turnover must use six-digit HSN codes, and the portal now requires selection from a dropdown rather than free entry.3e-Invoice System. e-Invoice System Each item also needs a description, quantity, unit price, GST rate, and tax amounts broken out by IGST or CGST/SGST. The invoice total must equal the sum of line items plus other charges minus discounts, with a tolerance of ₹1.
Document Details
The document type code (INV for a regular invoice, CRN for a credit note, DBN for a debit note), your sequential document number, and the document date. The supply type code identifies the transaction nature: B2B, export with payment, export without payment, SEZ supply, and so on.
Generating the E-Invoice Step by Step
1. Prepare the JSON File
Your invoice data must reach the IRP as JSON. Three options produce that file. The government’s free offline tool, GePP (Generate e-Invoice Preparation Product), lets you enter data through a spreadsheet-style interface and converts it to JSON.3e-Invoice System. e-Invoice System Most commercial accounting and ERP systems generate the JSON directly from your sales records. For high volumes, direct API integration with the IRP removes manual file handling entirely.
2. Upload to the IRP
Log in at einvoice1.gst.gov.in using your GSTIN credentials. Two-factor authentication has been mandatory for all taxpayers since April 2025.3e-Invoice System. e-Invoice System Upload the JSON through the portal interface or transmit it through an API, either directly or via a GST Suvidha Provider (GSP) acting as intermediary.
The portal validates the moment it receives your data. It confirms both GSTINs are active, checks that the document number hasn’t already been registered, verifies HSN codes against the master list, and checks that the arithmetic across line items adds up. If anything fails, the response includes a specific error code identifying the field.
3. Receive the IRN and Signed Invoice
When validation passes, the IRP generates a 64-character Invoice Reference Number using a SHA-256 hash of your supplier GSTIN, financial year, document type, and document number.5Goods and Services Tax e-Invoice System. IRN Invoice Reference Number The portal digitally signs the invoice, embeds a QR code, and returns the package to you.2Goods and Services Tax Network. E-Invoicing FAQs The QR code encodes both GSTINs, the invoice number and date, total value, number of line items, main HSN code, and the IRN. At that point, the invoice is officially registered.
If you include transport details at this stage (vehicle number, transport mode, distance), the IRP can auto-generate Part A of the e-way bill from the same submission for goods movements above ₹50,000, saving a separate entry on the e-way bill portal.
The 30-Day Reporting Deadline
If your aggregate turnover is ₹10 crore or more, you must report each e-invoice on the IRP within 30 days of the document date. This applies to invoices, credit notes, and debit notes alike. The portal rejects any document older than 30 days, and there is no manual override after the fact.6e-Invoice System. Advisory – Time Limit for Reporting e-Invoice on the IRP Portal Businesses below ₹10 crore currently face no such restriction, but reporting promptly still matters because delays hold up your buyer’s input tax credit.
Common Validation Errors and Fixes
The IRP returns numbered error codes. These are the ones most businesses run into:7Goods and Services Tax. Error Codes
- Error 2150/2154 (Duplicate IRN). You’ve already registered this document, sometimes from a simultaneous API request. Look up the existing IRN before re-submitting.
- Error 2172 (IGST on intrastate supply). You passed IGST for a transaction within the same state. Switch to CGST/SGST. If an exception genuinely applies, set the IGST_on_IntraState_Supply flag to “Y.”
- Error 2174 (CGST/SGST on interstate supply). The mirror problem. Use IGST for supplies between different states.
- Error 2176 (Invalid HSN code). The code isn’t in the master list. Cross-check using the portal’s Master Codes search.
- Error 2189 (Total invoice value mismatch). The total doesn’t equal line items plus other charges minus discounts. Recalculate within the ₹1 tolerance.
- Errors 2182–2187 (Tax value mismatches). Invoice-level tax amounts don’t match the sum of line-item taxes. Verify taxable value, CGST, SGST, IGST, and cess separately.
- Error 2163 (Future document date). Correct the date field.
Most failures reduce to arithmetic mismatches or the wrong tax type for the state pairing. If you see Error 2146 or 2147 during API-based IRN creation, these are usually temporary server issues and a retry works.
Cancelling an E-Invoice
You can cancel a registered e-invoice within 24 hours of reporting it.2Goods and Services Tax Network. E-Invoicing FAQs After that, the portal locks the record permanently. There is no way to edit a registered e-invoice. If you catch an error later, your only route is a credit note or debit note against the original, registered through the same e-invoice process so the audit trail stays intact.
The 24-hour clock starts when the IRN is generated, not from the invoice date. In batch API workflows, watch each IRN’s timestamp so you know when the window closes. Cancellation via API requires that the requesting GSTIN matches the supplier GSTIN on the original invoice; a mismatch triggers Error 2143.
What Happens After the IRN Is Generated
Once the IRN is created, the invoice details auto-populate the relevant tables of your GSTR-1 based on the document date, with item-level details aggregated at the rate level.8GST Tutorial. Advisory on Auto-Population of E-Invoice Details Into GSTR-1 Non-e-invoice supplies such as B2C transactions still need to be added manually. Editing or deleting an auto-populated entry breaks the IRN linkage, and the portal then treats the document as a manual upload. Only edit when the auto-populated data genuinely doesn’t match your actual invoice.
On the buyer’s side, a valid e-invoice flows from the supplier’s GSTR-1 into the buyer’s GSTR-2B, making the input tax credit visible and claimable. This chain is the reason e-invoicing exists, and it’s also why a missing IRN causes problems on both ends.
Consequences of Not Generating an E-Invoice
Under Section 16(2)(a) of the CGST Act, a buyer can only claim input tax credit if they hold a valid tax invoice.9CBIC Tax Information. CGST Act Section 16 Rule 48(5) states that an invoice issued by a taxpayer required to generate an e-invoice, but who does not, is treated as if no invoice was issued at all.1CBIC Tax Information. CGST Rule 48 Practically: without an IRN, your invoice doesn’t appear in the buyer’s GSTR-2B, and the buyer cannot claim ITC. Buyers often refuse delivery or hold payment until the supplier registers a proper e-invoice.
On penalties, Section 122(1)(i) sets a penalty of ₹10,000 or the amount of tax evaded, whichever is higher, for supplying goods or services without issuing a proper invoice. Because Rule 48(5) treats a missing IRN as no invoice, each non-compliant sale can qualify. Section 122(3)(e) separately imposes a penalty of up to ₹25,000 for failing to issue an invoice in accordance with the Act or rules.10CBIC Tax Information. CGST Act Section 122 These apply per invoice, and repeated non-compliance compounds quickly.