E-Invoicing in Singapore

The GST InvoiceNow Requirement represents a significant upgrade to Singapore's GST environment, marking a decisive move toward real-time tax reporting and a fully digital tax system. This is achieved by expanding the pre-existing Peppol e-invoicing network from a traditional four-corner model into a five-corner framework.

The core change is the introduction of a mandate that GST-relevant invoices must be transmitted not only to the trading partner (B2B exchange) but also directly to the Inland Revenue Authority of Singapore (IRAS), establishing the IRAS as the fifth corner in the exchange.

The requirement is being introduced progressively. Voluntary submission was made available to all GST-registered businesses starting 1 May 2025. Mandatory submission then began on 1 November 2025 for new voluntary GST registrants registered for less than six months. This will be extended on 1 April 2026 to cover all new voluntary GST registrants. IRAS has also declared its intention to eventually broaden the mandate to include all existing GST-registered businesses in a future, yet-to-be-confirmed phase.

All GST-relevant invoices, irrespective of their original transmission method, must first be transformed into the PINT SG format. This document must then be encapsulated in an SBDH (Standard Business Document Header) envelope before submission to IRAS. While B2B invoice exchange continues through the Peppol network using the Peppol PINT SG format, the submission to IRAS is executed via a direct XML API, explicitly bypassing the Peppol infrastructure for this step. Only IMDA-accredited Access Points are authorised to handle this final step of submitting the invoice data to the tax authority.