Bulletin
4notify Singapore · Government Gazette
OFFICIAL · IRAS · IMDA · InvoiceNow · Peppol PINT-SG
Bulletin No
BUL-SG-003
Date
2026-05-27
Status
In force
Category
Taxation

GST, InvoiceNow and Peppol PINT-SG: delivery acknowledgements and validation reports for Singapore businesses

Whereas, in exercise of the powers conferred by the Goods and Services Tax Act, the Inland Revenue Authority of Singapore (IRAS) runs the GST regime, and the IMDA InvoiceNow service has, since 1 May 2025 for newly incorporated GST-registered companies, become the national e-invoicing network on the Peppol PINT-SG specification. Every GST-registered taxpayer must issue invoices through InvoiceNow and stream the transmission data to IRAS. 4notify integrates with the local ERPs and accounting platforms and delivers ACKs, validation reports and tax-side notifications to the right Approved Accountant.

EmailWebhook
Preamble

Whereas, in exercise of the powers conferred by the Goods and Services Tax Act and the IRAS guidance on the GST InvoiceNow Requirement, the present Bulletin is hereby published concerning the delivery of e-invoicing acknowledgements over the Peppol PINT-SG specification.

Statutory basis
Goods and Services Tax Act (Cap. 117A)

Statutory basis for GST registration, supply rules and the e-invoicing requirement.

IRAS guidance on GST InvoiceNow

Mandatory adoption schedule for newly incorporated and existing GST-registered companies.

Peppol PINT-SG specification

Singapore localisation of the international Peppol PINT base; technical envelope for InvoiceNow.

Implementation
01

Accounting platform webhook

4notify subscribes to the InvoiceNow outbound queue of the ERP or accounting platform; validation runs at the API edge before relay to the Peppol Access Point.

02

Acknowledgement and validation report

Issuer-side ACK in 60 seconds; validation status (accepted / accepted with remarks / rejected) within 5 minutes.

03

Routing to the Approved Accountant

Using the practice's UEN, the ACK is routed to the right Approved Accountant for the GST-registered taxpayer.

04

Seven-year retention

Each envelope and ACK is retained for seven years with a hash signature, in line with the GST record-keeping obligation.

Delivery envelope
xml
<invoice-ack xmlns="https://4notify.net/invoicenow-sg/v1">
  <peppol-id>0195:SG200912345A</peppol-id>
  <supplier-uen>200912345A</supplier-uen>
  <buyer-uen>199801234B</buyer-uen>
  <document-type>Invoice</document-type>
  <pint-sg-profile>urn:peppol:pint:billing-1@sg-1</pint-sg-profile>
  <validation-state>accepted</validation-state>
  <ack-channel>email,webhook</ack-channel>
  <accountant-uen>53112233A</accountant-uen>
</invoice-ack>
Sample message
EmailSubject: Acknowledgement: InvoiceNow PINT-SG envelope …481923

Dear Taxpayer, We have received and validated your InvoiceNow envelope (ID …481923) on 27 May 2026 at 14:32 SGT. Validation state: accepted Routed to: Approved Accountant (UEN 53112233A) Regards, 4notify Operations

Compliance checklist
  • ERP / accounting platform InvoiceNow webhook configured
  • PINT-SG envelope validation at the API edge
  • ACK P50 measured at or below 60 seconds
  • Seven-year retention documented for GST audit
The 4notify difference

4notify is the only A2P provider with native integration into Singapore accounting platforms, API-edge validation of the Peppol PINT-SG envelope and seven-year signed audit custody aligned to the IRAS GST e-invoicing requirement.

Frequently asked questions
Does 4notify need to be a Peppol Access Point itself?

No. 4notify operates downstream of the customer's Peppol Access Point: it consumes the outbound envelope, validates it, delivers the ACK and routes the validation report to the right human. The Peppol AP layer stays with the accounting platform.

What about businesses that are not GST-registered?

Voluntary InvoiceNow adoption is encouraged but not mandated for non-GST taxpayers. 4notify still delivers the same ACK envelope for any participating supplier, which preserves a consistent audit trail when the company crosses the GST threshold.

Published
4notify Operations Office
2026-05-27 · BUL-SG-003

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