From 1 April 2026, businesses that voluntarily register for GST in Singapore must transmit invoice data to IRAS via the InvoiceNow network. The mandate then phases progressively to cover all GST-registered businesses, with full rollout targeted by 1 April 2031. It is the single biggest accounting-systems change for Singapore SMEs since GST went to 9% in January 2024, and most of the operators we've spoken to in the past quarter still don't know it's coming.

This piece is the operator version. Five questions, answered honestly. We'll keep it short.

What is InvoiceNow, actually?

InvoiceNow is Singapore's nationwide e-invoicing network. It's run by IMDA — the Infocomm Media Development Authority — and built on the international Peppol framework, the same standard the EU, Australia, and a growing list of countries have adopted.

Practically: instead of sending a PDF invoice over email, your accounting system sends a structured invoice document directly to your customer's accounting system through the Peppol network. The customer's system receives it as data, not as a document you have to retype.

For GST purposes, IRAS will receive the relevant invoice data through the same network. Less re-keying. Fewer reconciliation gaps. In the long run, faster and more accurate GST reporting.

Who's affected on 1 April 2026?

Voluntary GST registrants — businesses that choose to register for GST even though their turnover is below the S$1 million threshold. From 1 April 2026, voluntary registrants must submit relevant invoice data via InvoiceNow.

If you're already voluntarily GST-registered, this affects you. If you're considering voluntary registration this year, this affects you. If you're a new business incorporating in 2026 and voluntarily registering, this affects you from day one.

The compulsory rollout to all GST-registered businesses is then phased through 2027–2031. By 1 April 2031, every GST-registered business in Singapore is expected to be on InvoiceNow. The exact timing for each tranche is set by IRAS.

What do you actually have to do?

Three things, in order.

  1. Be on a Peppol-ready accounting system. Xero is. QuickBooks Online is. MYOB's newer products are. QuickBooks Desktop is not. Spreadsheets are not. If you're still on either of those, you have a system migration ahead of you, and 2026 is the year to do it.
  2. Register with IMDA / a Peppol Access Point. Your accounting software vendor will typically handle this, but the registration sits with your business. There's a one-time onboarding step.
  3. Set up your supplier and customer master data properly.The whole network works on Peppol IDs. Each customer and supplier you transact with needs the right identifier in your system. Easier than it sounds, but it's not zero-effort.

What changes for receipts and supplier invoices?

The InvoiceNow mandate currently focuses on your outbound invoices to customers — and the data IRAS receives from those. Inbound supplier invoices and receipts continue to be captured the way you capture them today.

In practice, if you're running on Xero with a receipt capture flow (Hubdoc / Dext, or our Receipt Catcher agent routing from WhatsApp/email/photo into the ledger), nothing about that flow changes in April. The change is on the other side — what your accounting system sends out.

What we'd do now if we were you

If you're running a GST-registered business in Singapore, here's the honest priority list for the next 12 months:

  • Confirm what accounting software you're on. If it's spreadsheets, QuickBooks Desktop, or an older local system that isn't Peppol-ready, your priority is to migrate. Don't leave that to Q1 2027.
  • If you're on Xero, talk to your accountant about enabling the InvoiceNow integration ahead of the date — not on it. The first few weeks of any mandate are messy, and you don't want to be debugging Peppol Access Point issues while also doing your GST F5.
  • Clean up your customer and supplier master data. Names, UENs, Peppol IDs where available. The migration is a good time to audit who's still active and who hasn't traded with you in three years.
  • If you're thinking about voluntary GST registration in 2026, factor in the InvoiceNow obligation. It's not a reason to avoid voluntary registration, but it is a reason to plan the system migration alongside it rather than sequentially.
What we're telling clientsFor Acuitas clients on Xero, we're building the InvoiceNow readiness step into the standard onboarding from Q4 2025. By the time the mandate lands in April 2026, the integration will be live, master data will be clean, and your first compliant GST cycle should run without drama.

The full IRAS guidance lives at iras.gov.sg. If you want help working out where your business sits and what the actual cutover looks like for your stack, talk to us.

— The Acuitas team