Under GST e-invoicing the supplier still prepares the invoice in its own accounting or ERP system. What changes is that the prescribed invoice data is reported to an Invoice Registration Portal (IRP), which validates it and returns an Invoice Reference Number (IRN) and a signed QR code. Once that has happened, the room to fix a mistake is narrow: the IRP does not allow amendment, cancellation is possible only for 24 hours, and a careless retry can throw a duplicate error. This guide sets out what the IRP permits, what to do in each situation and how to keep the audit trail clean.
Who is inside e-invoicing
The IRP's note on the e-invoice mandate records that e-invoicing was extended to taxpayers with turnover above ₹5 crore from 1 August 2023 under Notification No. 10/2023. The same note lists the entities exempt under rule 48(4): banks, insurance companies and financial institutions including NBFCs, goods transport agencies, passenger transport services, suppliers of admission to film exhibitions and SEZ units. Covered transactions are B2B, B2G, exports, deemed supplies and deemed exports, and SEZ developer supplies. The documents to be reported are the supplier's invoices, credit notes and debit notes. B2C supplies, imports and job work are outside the mandate, and a bill of supply or a delivery or job work challan need not be reported.
The IRP's FAQ adds that once e-invoicing applies to a business, it continues to apply even if turnover later falls.
How the IRN is built and why that matters for errors
According to the IRP's IRN explainer, the IRN "is hash of Supplier GSTIN + Fin. Year + Doc Type + Doc Number", generated with SHA-256, and is 64 characters long. It is unique across the GST system.
Two practical consequences follow. First, the IRN does not depend on the amount, the buyer or the items, so fixing those fields in the ERP and resubmitting the same document number produces the same hash, which the IRP rejects as a duplicate. Second, a cancelled document number cannot simply be reused: the FAQ states that the IRN used in a cancelled invoice "cannot be used again for another invoice". The corrected document needs a new number.
What the IRP allows after an IRN is generated
| Action | Allowed? | Condition |
|---|---|---|
| Amend the e-invoice on the IRP | No | "Once the invoice is furnished through the portal it cannot be amended." |
| Cancel the IRN | Yes | Within 24 hours of generation; any e-way bill must be cancelled first |
| Cancel after 24 hours | No | "We cannot cancel an e-invoice after the expiry of 24 hours in any condition whatsoever." |
| Delete all trace | No | A cancelled e-invoice leaves a record that it was generated |
| Correct after 24 hours | Through a credit note or debit note | The note is itself a document reported to the IRP |
Cancelling within 24 hours
The IRP's cancellation guide says only records with an active IRN generated in the last 24 hours are considered for cancellation. The user must select a reason and enter remarks; both are mandatory. Where an e-way bill has been generated against the invoice, the FAQ says the e-way bill has to be cancelled first, and both cancellations must happen within 24 hours.
Time limit for reporting to the IRP
An invoice cannot be reported to the IRP at any time the supplier likes. The IRP's notice on the reporting deadline requires taxpayers with annual aggregate turnover of ₹100 crore or more to report invoices "within 30 days from the invoice date", covering all documents that need an IRN, including credit and debit notes. Its example: an invoice dated 1 November 2023 must be reported by 30 November 2023. On the same count, an invoice dated 20 August 2026 must be reported by 18 September 2026. IRP advisories on this limit are updated from time to time, so check the current one for the turnover band that applies to your client.
The practical rule for every business: never back-date invoices to fix a missed IRN, and clear the IRP exception queue daily rather than at month-end.
Common validation errors and their causes
The IRP's troubleshooting guide lists the error codes. Those finance teams see most:
| Code | Message | Usual cause and fix |
|---|---|---|
| 2150 | Duplicate IRN | Same document sent again, often after a timeout. Update the ERP with the IRN when the response arrives and do not fire the same request twice. |
| 2211 | Supplier and recipient GSTIN should not be the same | Self-addressed invoice; use distinct GSTINs. |
| 2212 | The recipient GSTIN cannot be URP for supply type | B2B supply to an unregistered person; enter the buyer's actual GSTIN or treat as B2C. |
| 2163 | The document date should not be future date | Date field or system clock wrong. |
| 2172 | For intra-State transaction, IGST is not applicable | Place of supply mismatch; charge CGST and SGST, unless an exception applies and is flagged. |
| 2176 | HSN code is invalid | Outdated or mistyped HSN; check against the portal master. |
| 2240 | GST rate of tax is incorrect or not as notified | Rate field does not match a notified rate. |
| 2283 | IRN details cannot be provided as it is generated more than the permitted days prior | Trying to fetch an old IRN; historical data is available only for a limited period. |
Worked examples
1. Wrong buyer GSTIN, noticed the same day
An IRN is generated at 4:30 pm on 14 September 2026 for a ₹5,00,000 supply plus IGST at 18% (₹90,000), total ₹5,90,000. At 11 am the next morning the sales team realises the buyer's GSTIN belongs to a group company. The window closes at 4:30 pm on 15 September. The team cancels the e-way bill first, then cancels the IRN with the reason and remarks, and issues a fresh invoice under a new document number to the correct GSTIN. The cancelled number stays in the series with its cancellation record.
2. Same error, noticed three days later
The IRN can no longer be cancelled. The supplier issues a credit note for the full ₹5,90,000 against the original invoice, reports the credit note to the IRP to get its own IRN, and issues a new invoice with a new number to the correct buyer, also reported to the IRP. Both documents flow to GSTR-1. The wrong buyer should be told that the credit note reverses the original, so its purchase records match.
3. Overcharged value
An invoice is reported at ₹2,00,000 plus 18% GST (₹36,000), total ₹2,36,000. The agreed price was ₹1,50,000 plus ₹27,000, total ₹1,77,000. After 24 hours, the supplier issues a credit note for the difference: taxable value ₹50,000 and GST ₹9,000, total ₹59,000, reported to the IRP. The original IRN stays; the credit note corrects the value.
4. Undercharged value
If the invoice was reported at ₹1,50,000 but the agreed price was ₹2,00,000, the correction runs the other way: a debit note for ₹50,000 plus ₹9,000 GST, reported to the IRP within the applicable time limit.
5. Timeout and retry
The ERP sends an invoice to the IRP and the connection times out. The ERP shows "failed". The IRP had in fact generated the IRN. A second send returns error 2150. The fix is procedural: before any retry, query the IRP for that document number, and if an IRN exists, write it back to the ERP and print the QR code from that response.
Error-handling workflow for finance teams
- Validate before sending: maker-checker on buyer GSTIN, place of supply, HSN, rate and document number.
- Capture the response: store the IRN, acknowledgement number and date and signed QR code against the document.
- Check before retrying: query the IRP after a timeout instead of resending.
- Classify the error: schema or validation failure, business-data error, or duplicate.
- Act inside 24 hours: if cancellation is needed, cancel the e-way bill, then the IRN, and document the reason.
- After 24 hours, use notes: a credit or debit note with its own IRN; never a second invoice for the same supply.
- Keep the trail: the original invoice, IRP responses, cancellation records and notes.
Record retention
The GSTN's FAQ on e-invoice JSON download states that "the e-Invoice JSON is available for download for 6 months from the date of IRN generation", to both suppliers and recipients with active GSTINs, through the e-Invoice JSON download tile on the e-invoice portal dashboard. Portal availability is not a record-keeping system, so download and archive the signed JSON in your own system.
Updated on 27 September 2026: retitled; added the e-invoice mandate threshold and exemptions, how the IRN hash makes document numbers non-reusable, the 30-day reporting rule, an error-code table and five worked correction scenarios with figures.
