GST e-invoicing is often misunderstood as a requirement to prepare invoices on a government portal. That is not how the system works. A business generally continues creating invoices in its accounting or ERP system, but where the e-invoicing mandate applies, specified invoice data must be reported to an authorised Invoice Registration Portal (IRP). The IRP validates the data and returns an Invoice Reference Number (IRN) and digitally signed QR code.
For finance teams, the useful questions are therefore not only whether e-invoicing applies, but also which transactions need IRN, which entities are exempt, how quickly documents must be reported, and what to do when an invoice contains an error.
When does GST e-invoicing apply?
The current mandate applies to registered persons whose aggregate annual turnover has exceeded ₹5 crore in any preceding financial year from FY 2017-18 onward, subject to the notified exclusions. The authorised IRP's e-invoicing mandate page explains that turnover in any preceding financial year from 2017-18 onward is considered for applicability. The threshold was reduced to ₹5 crore with effect from 1 August 2023.
This historical test matters. A business should not decide applicability merely by looking at current-year turnover. If the relevant turnover threshold was crossed in an earlier financial year covered by the notification framework, the mandate may continue to apply even if current turnover is lower.
Which transactions and documents are covered?
For a taxpayer covered by the mandate, e-invoicing primarily applies to specified B2B and other notified outward transactions rather than every invoice issued by the business. The authorised IRP's e-invoicing FAQ identifies B2B supplies, deemed supplies, supplies by SEZ developers, exports, deemed exports, credit notes and debit notes among the covered categories.
The same official FAQ distinguishes transactions that are not covered by the current e-invoice mandate, including B2C supplies, bills of supply, imports, exempt supplies and job-work transactions as such. This is why an accounts team should not configure its ERP to send every sales document blindly to the IRP.
What exactly is an IRN?
An IRN is the unique reference generated when invoice data is successfully registered with the IRP. The e-invoice also carries a digitally signed QR code returned by the IRP. The practical workflow is straightforward: create the invoice in the accounting system, convert or map the required data into the prescribed schema, transmit it to an authorised IRP, receive the IRN and signed QR code, and then issue or render the invoice with the required e-invoice particulars.
E-invoicing also supports downstream reporting. The authorised IRP's mandate guidance notes that e-invoice information is passed onward to the GST system, reducing duplicate data entry for GSTR-1. Businesses should still reconcile auto-populated data with their books rather than assuming that successful IRN generation replaces return review.
The important 30-day reporting rule for AATO of ₹10 crore and above
There is an additional operational restriction for larger taxpayers. Effective 1 April 2025, taxpayers with aggregate annual turnover of ₹10 crore and above must report invoices, credit notes and debit notes to the IRP within 30 days from the document date. The authorised IRP's 30-day reporting advisory states that the system restricts IRN generation when such a document is reported beyond the permitted 30-day window.
This rule should not be confused with the general ₹5 crore e-invoicing applicability threshold. A taxpayer may fall within the e-invoicing mandate because its turnover crossed ₹5 crore, while the specific 30-day IRP reporting restriction applies to the ₹10 crore-and-above category.
Which entities are exempt?
The e-invoicing framework contains entity-level exemptions. The authorised IRP's Rule 48(4) guidance lists categories including insurance companies, banks and specified financial institutions including NBFCs, goods transport agencies, suppliers of passenger transportation services, suppliers of services by way of admission to exhibition of films, and SEZ units. The distinction between an SEZ unit and an SEZ developer is important: the IRP guidance states that SEZ units are exempt, while an SEZ developer can be covered when the other applicability conditions are met.
An entity that appears enabled on an e-invoice portal should therefore not assume that portal enablement itself overrides a statutory exemption. Applicability should be documented against the notified class, turnover history and nature of the entity.
Can an e-invoice be cancelled or edited?
An IRN can be cancelled within the permitted system window, but direct editing of an already registered e-invoice is not the normal correction route. The authorised IRP's IRN cancellation guidance states that only active IRNs generated within the last 24 hours are considered for cancellation through that facility.
This makes pre-upload validation important. If a GSTIN, invoice number, taxable value, tax amount or other material field is wrong, the finance team should identify the error before IRN generation wherever possible. Once the 24-hour cancellation window has passed, correction must be handled through the applicable GST reporting and document mechanism rather than by simply editing the registered IRN.
Worked example: which rule applies?
Assume an Indian consulting company had aggregate annual turnover of ₹7 crore in FY 2024-25 and issues a taxable B2B service invoice in August 2026. Ignoring any entity exemption, the historical turnover exceeds the ₹5 crore e-invoicing threshold, so the company should test the invoice under the e-invoicing mandate. However, on these facts its AATO is below ₹10 crore, so the separate 30-day IRP reporting restriction for the ₹10 crore-and-above category does not arise merely because e-invoicing itself applies.
Now assume another company had AATO of ₹14 crore. Its covered invoices are subject not only to e-invoicing but also to the 30-day reporting restriction. An invoice dated 1 August should therefore be reported within the applicable 30-day system window; delaying it beyond that period can prevent IRN generation.
Practical implementation checklist
- Build a turnover history: review aggregate annual turnover for preceding financial years from FY 2017-18 onward instead of checking only the current year.
- Test entity exemptions: document whether the supplier falls within a notified exempt class.
- Map transaction types: separate B2B, exports, deemed exports, credit notes and debit notes from B2C, exempt and other non-covered documents.
- Configure ERP validations: validate GSTIN, document number, date, tax values, place-of-supply data and other required fields before sending data to the IRP.
- Track the 30-day clock where applicable: taxpayers with AATO of ₹10 crore and above should monitor document age so that covered documents do not become time-barred for IRN generation.
- Control cancellations: investigate errors immediately because IRN cancellation through the portal is time-limited.
- Reconcile downstream data: compare IRP records, books and GSTR-1 rather than treating auto-population as a substitute for review.
Common mistakes to avoid
- Checking only current-year turnover and ignoring an earlier year in which the threshold was crossed.
- Assuming the ₹10 crore 30-day rule is the basic e-invoicing threshold; the broader mandate begins at the notified ₹5 crore threshold.
- Sending B2C or exempt-supply documents to the IRP merely because the supplier is otherwise covered by e-invoicing.
- Treating SEZ units and SEZ developers as identical for e-invoicing applicability.
- Waiting until return filing to discover an invoice error after the IRN cancellation window has closed.
- Assuming successful IRN generation eliminates the need to reconcile GSTR-1 with the sales register.
Practical takeaway
GST e-invoicing is best managed as a controlled invoice-registration process, not as a separate invoicing system. Start with historical turnover and entity exemptions, identify the covered transaction types, validate data before IRP submission, and distinguish the ₹5 crore applicability threshold from the separate 30-day reporting restriction for taxpayers with AATO of ₹10 crore and above. A disciplined ERP-to-IRP-to-GSTR-1 reconciliation process prevents most avoidable e-invoicing errors.
