GST-registered businesses in Singapore are being brought, in phases, into a requirement called GST InvoiceNow. That means sending invoice data straight to IRAS will be part of your GST reporting. If you are not sure whether this applies to you yet, when your deadline falls, or how it is different from the general InvoiceNow network your accountant may have mentioned, this guide covers all three directly. We also look at a detail most articles skip: how the Productivity Solutions Grant (PSG) can offset the cost of getting InvoiceNow-ready, and the mistakes businesses commonly make during adoption.
What Is InvoiceNow?
InvoiceNow is Singapore’s nationwide e-invoicing network, built on the international Peppol standard. It was introduced by IMDA in 2019 to let businesses exchange invoices directly between accounting systems, replacing PDFs, email attachments and manual re-keying with structured digital data.
The network runs on what is called a 4-corner model. Your business (corner 1) sends an invoice through your accredited access point (corner 2), which routes it to your customer’s access point (corner 3), which delivers it to your customer (corner 4). Adoption has been voluntary since launch, and any business can use it, whether it is GST-registered or not.
What Is GST InvoiceNow?
GST InvoiceNow is a separate, newer requirement from IRAS that sits on top of the InvoiceNow network. GST-registered businesses that fall within its rollout schedule must also transmit their invoice data directly to IRAS, alongside sending it to the customer as usual.
This adds a fifth party to the exchange, turning the 4-corner model into a 5-corner model, with IRAS receiving a copy of the invoice data for GST reporting purposes. Singapore is the first country to implement e-invoicing this way, and unlike general InvoiceNow adoption, GST InvoiceNow is mandatory once your business reaches its applicable date.
InvoiceNow vs GST InvoiceNow: Key Differences
The two terms get used interchangeably, but they are not the same thing. The table below sets out the core differences.
| Aspect | InvoiceNow | GST InvoiceNow |
|---|---|---|
| What it is | Nationwide e-invoicing network | Mandatory GST data reporting layer on top of InvoiceNow |
| Introduced by | IMDA (2019) | IRAS |
| Model | 4-corner (supplier to buyer) | 5-corner (adds IRAS as data recipient) |
| Participation | Voluntary for all businesses | Mandatory for GST-registered businesses |
| Data goes to | Buyer/supplier only | Buyer/supplier and IRAS |
| Format | Peppol BIS | PINT-SG (Peppol International Invoice – Singapore) |
How the 5-Corner Model Works
Understanding the flow of data helps explain why GST InvoiceNow exists and what changes for your business once you are in scope:
- Your business issues an invoice through your InvoiceNow-Ready accounting or invoicing software.
- The invoice is transmitted through your accredited access point in the structured PINT-SG format.
- Your access point routes the invoice to your customer’s access point.
- Your customer receives the invoice directly into their own accounting system, with no manual entry needed.
- Simultaneously, a copy of the invoice data is routed to IRAS, which is the additional step that distinguishes GST InvoiceNow from ordinary InvoiceNow.
Who Needs to Comply, and By When
GST-registered businesses are required to adopt the GST InvoiceNow Requirement progressively, with mandatory participation by the following groups of businesses in the following phases:
| Effective Date | Applies To |
|---|---|
| 1 Nov 2025 | Companies voluntarily registering for GST within 6 months of incorporation |
| 1 Apr 2026 | All new voluntary GST registrants |
| 1 Apr 2028 | New compulsory GST registrants + existing GST-registered businesses with annual supplies ≤ $200,000 |
| 1 Apr 2029 | Existing GST-registered businesses with annual supplies ≤ $1 million |
| 1 Apr 2030 | Existing GST-registered businesses with annual supplies ≤ $4 million |
| 1 Apr 2031 | All remaining GST-registered businesses (annual supplies above $4 million) |
If your business was already GST-registered before 2026, IRAS will notify you directly of your specific implementation date by mid-2026. You do not need to wait for that notice to start preparing, since choosing and testing a solution takes time.
Common Mistakes Businesses Make When Adopting GST InvoiceNow
Most compliance problems we see are avoidable. The most frequent ones include:
- Assuming it’s optional. Because InvoiceNow itself is voluntary, some businesses assume GST InvoiceNow is too. It is not, once your business reaches its applicable date.
- Leaving software selection to the last minute. Switching accounting systems or activating a new module close to your deadline leaves no room to troubleshoot data issues.
- Choosing a solution that isn’t accredited. Not every accounting package supports InvoiceNow out of the box. Confirm your software is on the IMDA-accredited InvoiceNow-Ready Solution list before committing.
- Paying the vendor before applying for PSG funding. If you sign a contract or pay a deposit before your PSG application is approved, you forfeit eligibility for that funding.
- Treating it as a replacement for GST filing. GST InvoiceNow changes how invoice data reaches IRAS. It does not remove the need to file your periodic GST return.
How to Get Started
- Confirm your GST registration type and check the compliance schedule above to estimate your applicable date.
- Check whether your current accounting or invoicing software is already on the IMDA-accredited InvoiceNow-Ready Solution list.
- If it is, ask your provider to activate the InvoiceNow module for your account.
- If it isn’t, shortlist a pre-approved solution and get a vendor quotation before making any payment.
- Look into PSG funding before signing anything, so you don’t lose eligibility for the subsidy.
- Set up and test the solution well ahead of your mandatory date, rather than waiting for IRAS’s notification.
Funding Support: Using PSG for GST InvoiceNow Adoption
This is the part most GST InvoiceNow guides leave out. Getting InvoiceNow-ready is not just a compliance exercise, it is also an eligible cost under the Productivity Solutions Grant (PSG), which can meaningfully reduce what your business pays out of pocket.
PSG Eligibility Criteria
To qualify for PSG support, your business generally needs to meet these conditions:
- Be registered and operating in Singapore, with at least 30% local shareholding
- Have a group annual sales turnover of S$100 million or less, or group employment of 200 or fewer employees
- Have not signed a contract, confirmed a purchase order, or made any payment to the vendor before the grant is approved
- Use a solution from Enterprise Singapore’s pre-approved PSG vendor list
What PSG Covers for InvoiceNow-Ready Solutions
PSG provides funding support of up to 50% of qualifying costs, capped at S$30,000 per company per financial year across all PSG applications combined. Eligible accounting and finance software packages, including those with InvoiceNow-Ready capability, fall within this scope. The grant is paid as a reimbursement, meaning you pay the vendor first and then claim back the supported portion, so approval needs to happen before any payment is made.
Application Process Tips
- Apply through the Business Grants Portal using your CorpPass account, before engaging or paying any vendor
- Get a formal quotation from a pre-approved vendor to include with your application
- Keep documentation ready, including your company’s financial and shareholding details, since these are checked against eligibility criteria
- Where possible, get advice on structuring the application correctly the first time, since PSG does not allow switching vendors partway through a claim
Frequently Asked Questions
InvoiceNow is the general e-invoicing network, voluntary for any business. GST InvoiceNow is a mandatory extension of it for GST-registered businesses, requiring invoice data to also be sent to IRAS.
It is compulsory for businesses that fall within IRAS's phased schedule, based on registration type and annual sales value. Full rollout to all GST-registered businesses completes by 1 April 2031.
Missing your date can create complications when filing your GST returns and may draw additional scrutiny from IRAS. There is no publicised grace period, so confirming your date early is worthwhile.
Yes, provided the solution is on Enterprise Singapore's pre-approved PSG vendor list and you apply for and receive approval before signing a contract or making payment.
No. It changes how invoice-level data reaches IRAS, but your periodic GST return filing obligations remain separate and unchanged.
A growing number of cloud accounting platforms support InvoiceNow, but not all versions or tiers do by default. Always confirm directly against the IMDA-accredited InvoiceNow-Ready Solution list rather than assuming your current plan includes it.
Use the IRAS GST InvoiceNow Implementation Date Calculator, or wait for IRAS's direct notification if your business was already GST-registered before 2026.
