Network and phased requirement
InvoiceNow is Singapore’s nationwide Peppol-based e-invoicing network for structured invoice exchange. The GST requirement makes GST-registered businesses submit invoice data to IRAS through it, with progressive mandatory phases. IRAS informs businesses of their mandatory implementation date; this short guide does not list all phase dates. It was published 24 June 2026.
Off-the-shelf accounting systems
Check that the existing accounting/finance solution appears on IMDA’s accredited InvoiceNow-Ready Solution Provider list, otherwise contact an accredited IRSP. The IRSP registers the UEN in the SG Peppol Directory to obtain a Peppol ID, then helps turn on the GST InvoiceNow Submission Feature. Network registration and enabling IRAS submission are separate onboarding steps.
Custom ERP or starting from scratch
Businesses with customised in-house ERP contact an IMDA-accredited Access Point Provider, the network connectivity gateway. The AP assists Peppol registration and ID, then enables invoice-data submission directly from ERP to IRAS. Businesses unsure where to start may acquire a free-of-charge InvoiceNow-ready solution or contact an accredited IRSP, then follow registration and submission activation.
Sales submission flows
Type 1A applies when supplier and customer are on the network: supplier issues an e-invoice and IRAS automatically receives a copy. Type 2 applies when the customer is off-network: supplier issues a regular invoice and separately submits its data to IRAS. Access points connect directly to IRAS through APIs.
Purchase submission flows
Type 1B applies when both parties are on-network: customer receives the supplier e-invoice and separately submits purchase data to IRAS. Type 3 applies when the supplier is off-network: customer receives a regular invoice and separately submits data. Automatic receipt on the supplier’s sale side is therefore not a substitute for the customer’s purchase submission flow.
What and when to submit
Generally submit invoice data reported in GST returns: standard-rated, zero-rated and exempt supplies, and standard-rated/zero-rated purchases. Transactions not reported in returns and excluded transactions specified in e-Tax Guide paragraph7.3 need not be submitted. Point-of-sale, simplified-tax-invoice and petty-cash purchases may be aggregated. Submit by the earlier of actual filing of the relevant return or its filing due date.
Readiness after onboarding
Train staff in the solution and requirement; the IRAS/IMDA webinar is recommended. Test different submission flows end to end and resolve solution-specific technical issues. Confirm how to contact IRSP/AP support; provider feedback may go to IMDA. Begin submitting early enough to identify and address problems before mandatory implementation.
Official source
This article independently explains the substantive contents of the official PDF, including the relevant conditions, procedures and annexes. The linked document remains the authoritative source for its original wording, and later changes should be checked separately.
Read the official PDF ↗