InvoiceNow (Peppol) E-Invoicing: What Singapore Businesses Need From Their Software

IRAS lists the phases on its GST InvoiceNow Requirement page. As of October 2026:

• 1 November 2025: companies that register for GST voluntarily within six months of incorporation.
• 1 April 2026: businesses that apply for voluntary GST registration on or after this date, whatever their incorporation date or business structure.
• 1 April 2028: businesses that apply for compulsory GST registration on or after this date, and existing GST-registered businesses with total annual supplies up to S$200,000.
• 1 April 2029: existing GST-registered businesses with total annual supplies up to S$1 million.
• 1 April 2030: existing GST-registered businesses with total annual supplies up to S$4 million.
• 1 April 2031: existing GST-registered businesses with total annual supplies above S$4 million.

Total annual supplies means the value in Box 4 of your GST returns for accounting periods ending in calendar year 2025. IRAS began notifying businesses registered before 2026 of their implementation dates from mid-2026, and publishes a calculator for checking. Overseas entities registered under the Overseas Vendor Registration regimes, and businesses registered for GST only because of the reverse charge, are excluded.

The schedule was announced at the Committee of Supply debate in February 2026, when the Government said it expects the change to bring about 90,000 more businesses onto the network.

The IRAS e-Tax Guide on the requirement makes a point many businesses miss: emailing a PDF invoice is not e-invoicing, because the customer still keys the details into its own accounts. On InvoiceNow, invoices travel as structured XML. The Singapore format, PINT-SG, launched in February 2024 and serves as the base data format for the GST requirement.

Invoice data reaches IRAS by one of two routes:

• Peppol invoices. When you invoice a customer who is on the network, a copy of the invoice data goes to IRAS automatically as the invoice is routed.
• Solution-extracted data. Paper or PDF invoices issued to individuals or to customers not on the network, and purchase invoices recorded in your accounts, are extracted from your InvoiceNow-Ready Solution and sent to IRAS regularly, for example daily or weekly.

The scope covers transactions reported in your GST return: standard-rated and zero-rated supplies and purchases, and exempt supplies. That includes tax invoices, simplified tax invoices, serially numbered receipts, debit notes and credit notes. Point-of-sale data, supplies with simplified tax invoices and petty cash purchases may be aggregated before submission. Deemed supplies, reverse charge transactions, exempt financial services and import permits are out of scope.

Data is due by the earlier of two dates: the day you file the relevant GST return, or that return's filing due date. Your existing GST obligations, including keeping records for at least five years, stay in place.

Use this list when you speak to your current vendor or compare replacements:

• Is the product on IMDA's accredited InvoiceNow-Ready Solutions list, and is the GST submission feature available on your plan?
• Will the vendor or its Access Point register your UEN in the SG Peppol Directory and issue your Peppol ID?
• Does it send and receive invoices in PINT-SG, including credit notes linked to the original invoice?
• How does it handle the solution-extracted route for paper invoices, PDF invoices and purchase invoices you key in?
• Can it aggregate point-of-sale or petty cash data where IRAS allows that?
• Does it flag GST wrongly charged by suppliers who are not GST-registered? IRAS notes that solution providers can build this validation in.
• Where do you see failed or rejected submissions, and who fixes them?
• Can you reconcile what was sent to IRAS against your GST return before you file?

IRAS sets out a separate path for businesses on their own enterprise systems: engage an IMDA-accredited Access Point provider, obtain a Peppol ID, work with the Access Point to connect your system to IRAS, and then switch on GST submission. IRAS says onboarding can take as little as three months, and most businesses finish within a year, depending on readiness and system set-up.

The engineering work sits between your system and the Access Point:

• Data mapping. Every invoice, credit note and purchase record must map to the PINT-SG fields, with tax categories, UENs and GST registration numbers in the right places.
• Outbound integration. Your system calls the Access Point's API when a document is issued, stores the response and retries on failure.
• Inbound integration. Supplier e-invoices arrive through the Access Point and should land in your purchase workflow, not in an inbox.
• Monitoring. A dashboard of sent, accepted and failed submissions per GST period, with alerts well before the filing date.
• Testing. A test run with the Access Point using real invoice samples, including edge cases such as partial credit notes.

This is integration work our developers take on, alongside your chosen Access Point provider, through our system integration services. If the invoicing module itself needs rebuilding, our custom software development work covers that too. We have built GST billing software for the Indian market, AccVora, so invoice data models are familiar ground. Singapore's Peppol format is a different standard, and the connection to IRAS always runs through an IMDA-accredited Access Point.

IRAS lists support for the transition. The GST InvoiceNow Transition Grant offers S$1,000 for SMEs with annual supplies up to S$4 million and S$5,000 for larger businesses, and an InvoiceNow Queen Bee Grant of S$25,000 is listed for larger businesses. IMDA publishes the eligibility rules. Free-of-charge solution packages with basic e-invoicing are available until 31 March 2031.

The February 2026 announcement also pointed SMEs to the Productivity Solutions Grant for subscription costs. Enterprise Singapore's PSG closed to new applications on 29 September 2026, and support for pre-approved digital solutions now sits under its EDGE Grant, so check EDGE's digital solution activities instead.

If your date is 1 April 2029, start the work in the first half of 2028. A practical sequence:

• Confirm your implementation date from IRAS's notification or calculator.
• Decide between an InvoiceNow-Ready Solution and an Access Point connection for your current system.
• Clean master data: customer UENs, GST registration numbers and tax codes.
• Map and test documents, including credit notes and purchase invoices.
• Go live a quarter before your date, so the first GST return under InvoiceNow is not also your first live test.

Is a PDF invoice sent by email compliant with InvoiceNow?

No. IRAS does not treat a PDF sent by email as e-invoicing. You can still send PDFs to customers who are not on the network, but the invoice data must reach IRAS through your InvoiceNow-Ready Solution.

Do our customers need to be on InvoiceNow?

No. Invoices to customers not on the network go to IRAS through the solution-extracted route, and you send the customer a paper or PDF invoice as before.

Our accounting software is not InvoiceNow-ready. What are our options?

Ask the vendor for its roadmap, move to a solution on IMDA's list, or connect your current system to an accredited Access Point. The right choice depends on how much your current system does beyond invoicing.

When is invoice data due?

At the latest by the GST return's filing due date, or earlier if you file that return before the due date.

Is funding available?

Yes. The GST InvoiceNow Transition Grant and free-of-charge solution packages are listed on IRAS's page, with eligibility details on IMDA's site.

If your ERP or custom system needs to connect to InvoiceNow, send us your document types and monthly volumes. After a short discovery call we send a written scope and a fixed quote for the integration work. Discuss your project.