InvoiceNow & GST E-Invoicing in Singapore: What SMEs Must Do

If your business is GST-registered in Singapore, e-invoicing is no longer optional — it is a phased legal requirement. The GST InvoiceNow Requirement is being rolled out by IRAS in stages between 2025 and 2031, and unlike most tax rules it applies regardless of your turnover. This guide explains what InvoiceNow actually is, who has to comply and by when, what it costs, and the practical steps to get your systems ready — in plain English.

What is InvoiceNow?

InvoiceNow is Singapore’s nationwide e-invoicing network. It is operated by the Infocomm Media Development Authority (IMDA) and built on Peppol, the international standard used for e-invoicing in dozens of countries. Instead of emailing a PDF that someone re-types into their accounting system, InvoiceNow sends a structured invoice straight from your finance software into your customer’s — machine to machine, no re-keying. IMDA is Singapore’s designated Peppol Authority, which is why local providers must be accredited to connect to the network. (See the official IMDA e-invoicing framework.)

What is the GST InvoiceNow Requirement?

The GST InvoiceNow Requirement is a separate, tax-specific obligation that IRAS has layered on top of the InvoiceNow network. In scope, GST-registered businesses must use an InvoiceNow-Ready solution to transmit invoice data directly to IRAS for tax administration. In short: InvoiceNow is the delivery network; the GST InvoiceNow Requirement is IRAS asking for a copy of that data at source. The full rules are on the IRAS GST InvoiceNow page.

Who must comply, and when?

The requirement is being phased in by GST-registration event and, for businesses already registered, by annual supply size. The phases below are from the IRAS FAQ (updated April 2026) and were extended to all GST-registered businesses at Committee of Supply 2026.

Source: IRAS, Frequently Asked Questions for GST InvoiceNow Requirement (Version 16 Apr 2026). Dates and bands are subject to change — confirm against IRAS before acting.

Is there a minimum revenue threshold?

No — and this is the part most businesses misread. Every GST-registered business is eventually in scope. The S$200,000, S$1 million and S$4 million figures only determine when an existing registrant must onboard, not whether it has to. The only genuine exemptions are overseas entities and businesses registered wholly under the reverse-charge regime. Even a dormant company filing nil GST returns falls into the earliest band.

What do you actually need to do to comply?

There are three practical steps, and most of the effort is in the first one:

1. Get an InvoiceNow-Ready solution. Either check whether your current accounting or ERP software is on IMDA’s accredited list, connect your existing system to the network through an IMDA-accredited Access Point, or switch to a ready-made solution — including the free packages offered to GST-registered SMEs.
2. Get a Peppol ID linked to your UEN and register on the Singapore Peppol Directory so other businesses can find and invoice you on the network.
3. Activate the GST InvoiceNow submission feature. Until you switch this on, your e-invoices still reach customers but are not transmitted to IRAS — so this step is what actually makes you compliant.

How does the data reach IRAS?

Singapore uses what is often called a five-corner model. Your system (corner 1) sends the invoice through your Access Point (corner 2) to your customer’s Access Point (corner 3) and into their system (corner 4). IRAS is the fifth corner: your accredited solution sends a copy of the invoice data to IRAS in parallel, via IRAS’s submission API. Importantly, IRAS is a silent participant — it receives the data but does not approve, delay, or sit in the middle of your invoice exchange. Invoices that originate outside the network (paper or PDF) are captured by keying them into your InvoiceNow-Ready solution, which then forwards the data.

What does it cost — and is there grant support?

Onboarding cost depends on your current software, but the support available is genuinely generous:

• Free solutions for SMEs — selected InvoiceNow-Ready solutions are available free of charge to GST-registered SMEs until March 2031.
• A transitional adoption grant — announced at Committee of Supply 2026: up to S$1,000 for SMEs and up to S$5,000 for larger businesses to offset onboarding costs (confirm the current amount and application window with IRAS).
• The Productivity Solutions Grant (PSG) — may co-fund eligible IT solutions (commonly up to 50% of qualifying cost, subject to the prevailing annual cap).

For a smaller business on standard cloud accounting software, compliance can cost very little. The bigger spend tends to be where invoicing lives inside a custom or older system that has to be connected to the network — more on that below.

Why bother — beyond avoiding penalties?

Treated as a compliance chore, e-invoicing is a cost. Treated as an operations upgrade, it pays back. Because invoices move machine-to-machine, you typically get paid faster, eliminate the data-entry errors that cause disputes, and remove a slice of manual admin from your finance team. It is the same logic we cover in the hidden cost of manual work — the compliance deadline is simply forcing a change that was worth making anyway.

When you need more than off-the-shelf

Most businesses on mainstream cloud accounting software will comply by enabling a feature or installing a plugin. You should look at custom API integration when your invoicing doesn’t live in a standard package: a bespoke ERP or order system, several disconnected tools that all raise invoices, very high invoice volumes, or industry workflows (logistics, healthcare, multi-outlet retail) where invoices are generated programmatically. In those cases the work is connecting your existing stack to the InvoiceNow network cleanly — which is exactly the kind of integration we build. The same applies if you are already planning identity or data flows like Singpass & Myinfo integration and want them handled together.

Disclaimer: AppTech System is a software development vendor, not a tax authority or accredited tax adviser. The GST InvoiceNow Requirement is administered by IRAS and the InvoiceNow network by IMDA; both set all rules, dates, thresholds, accredited providers, and grant terms, which are subject to change. Figures and dates here reflect IRAS/IMDA guidance current at the time of writing (June 2026) and are not tax advice. Verify your obligations on the official IRAS and IMDA websites or with a qualified tax professional.

About AppTech System — AppTech System is a Singapore custom-software team and the people behind the Automiq and BooknGo platforms, building web, mobile, AI and enterprise software for businesses in regulated industries. Talk to us.