By KYN AI Advisory Team — AI implementation specialists, Singapore
Every GST-registered business in Singapore must send its invoice data to IRAS through InvoiceNow, on a phased schedule. New voluntary GST registrants are already covered. Existing registrants follow by annual supplies: up to S$200,000 from 1 April 2028, up to S$1 million from 1 April 2029, up to S$4 million from 1 April 2030 and above S$4 million from 1 April 2031. InvoiceNow runs on the Peppol network. You need an InvoiceNow-Ready solution or an accredited access point, and a Peppol ID tied to your UEN.
What is InvoiceNow, and how does Peppol fit?
InvoiceNow is Singapore's national e-invoicing network. It is built on Peppol, an international standard for exchanging invoice data between systems. A business sends a structured invoice from its software to a Peppol access point, and the access point delivers it to the buyer's software, and for GST purposes to IRAS.
Two terms matter:
- Peppol ID. A unique identifier, based on your UEN, that registers you in the SG Peppol Directory.
- Access Point Provider. A company accredited by IMDA that connects your system to the network.
A PDF emailed to a customer is not an InvoiceNow invoice. InvoiceNow carries structured data, so the receiving system can read the lines, tax and totals without retyping.
Which businesses must comply, and when?
IRAS publishes the schedule on its page for the GST InvoiceNow requirement/gst-invoicenow-requirement). The rule: all GST-registered businesses must submit invoice data to IRAS using InvoiceNow-Ready solutions.
| From | Who | |---|---| | 1 November 2025 | Companies that register for GST voluntarily within 6 months of incorporation | | 1 April 2026 | Businesses applying for voluntary GST registration on or after this date | | 1 April 2028 | Businesses applying for compulsory GST registration on or after this date, and existing GST-registered businesses with annual supplies up to S$200,000 | | 1 April 2029 | Existing GST-registered businesses with annual supplies up to S$1 million | | 1 April 2030 | Existing GST-registered businesses with annual supplies up to S$4 million | | 1 April 2031 | Existing GST-registered businesses with annual supplies above S$4 million |
Annual supplies means the total of standard-rated, zero-rated and exempt supplies, which is Box 4 of the GST return, across the prescribed accounting periods ending in calendar year 2025.
Exemptions: overseas entities, including certain Overseas Vendor Registration regimes, and businesses liable for GST only under the reverse charge.
IRAS has also notified businesses registered before 2026 of their implementation date from mid-2026. If you did not receive a notice, IRAS offers a GST InvoiceNow Implementation Date Calculator on the same page. Use it to confirm your date, not this table alone. IRAS announced the extension to all GST-registered businesses by April 2031 in its Committee of Supply 2026 release.
How do you connect? Two routes
IRAS describes two routes.
Route 1: off-the-shelf software. Choose a solution from IMDA's accredited list of InvoiceNow-Ready Solutions. IRAS notes that free packages are available. Your provider registers your business in the SG Peppol Directory with your UEN to obtain a Peppol ID, and you activate the GST InvoiceNow submission feature.
Route 2: in-house system. If you run your own invoicing system, engage an IMDA-accredited Access Point Provider. Obtain the Peppol ID through them, work with them to connect your system to IRAS, then activate submission.
| Question | Route 1: software | Route 2: in-house system | |---|---|---| | Who sends the data | The software provider | Your system, via an access point | | Setup effort | Low | Higher: mapping, testing | | Fit | Standard invoicing, few exceptions | Custom billing, volume, special terms | | Ongoing work | Follow the provider's updates | Maintain the mapping and monitor delivery |
IRAS states that onboarding may take as little as 3 months and that most businesses finish within a year. Start earlier than the deadline implies, because onboarding competes with your busiest months.
What changes in your invoicing process?
InvoiceNow moves invoice data. It does not decide tax treatment, and it does not replace the GST return. Your obligations to code each supply correctly and file accurate returns remain.
Five changes follow.
- Clean customer and supplier master data. UENs, GST numbers and addresses must be right, because the data travels as fields.
- Structured invoice lines. Description, quantity, unit price, tax code and totals as separate fields. Free-text invoices in a word processor do not fit.
- Consistent tax codes. Standard-rated, zero-rated, exempt and out-of-scope supplies each need a correct code on every line.
- Credit notes and corrections. A correction is a new document linked to the original. Build the process before you need it.
- Delivery monitoring. A failed transmission needs an owner who sees it the same day.
What should an SME with custom invoicing do?
Companies that bill from a spreadsheet, a custom tool or an ERP with bespoke fields should map the invoice before choosing a route.
- Export 50 recent invoices, including credit notes and one unusual case.
- List every field and where it comes from.
- Check each against the structured data the network needs. Ask your software provider or access point for the field specification.
- Fix master data gaps first: missing UENs, inconsistent customer names, blank tax codes.
- Test in a sandbox, if the provider offers one, before going live.
If your volume is low and billing is standard, route 1 with a free or low-cost package is usually enough. If you have custom pricing, many tax cases or links to other systems, route 2 gives control but needs build and monitoring.
How does InvoiceNow affect bookkeeping and reconciliation?
Structured invoice data helps downstream work. A purchase invoice that arrives as data can create the bill in your ledger without retyping, with the tax code already attached. Matching a receipt to a bank line becomes simpler when the invoice number and total are fields.
The risk moves to exceptions. Invoices that arrive outside the network, from overseas suppliers or small vendors, still need capture. A system should hold both flows in one ledger. See how to automate bank reconciliation in Singapore and how to scan receipts for GST claims in Singapore.
Where KYN fits
KYN builds finance and integration systems in your own cloud account. For a custom billing process, we map the invoice fields, connect the system to an accredited access point of your choice, and log every transmission with the actor and time. Sending, money and filings wait for a named person. KYN is not an access point provider. You choose the provider and hold the Peppol ID.
For InvoiceNow, we spend the first 14 days checking your accounting software, your Peppol access point options and how invoices leave the building today. The connected build ships in under 90 days. See integrations and finance systems.
Frequently asked questions
Do I need InvoiceNow if I am not GST-registered?
IRAS's requirement applies to GST-registered businesses. If you are not registered, the requirement does not apply to you. It will apply once you register: businesses applying for compulsory registration on or after 1 April 2028 are covered from the start.
Is a PDF invoice sent by email enough?
No. IRAS requires invoice data submitted through InvoiceNow-Ready solutions. A PDF can still go to your customer if they want one, but the structured data must reach IRAS through the network.
What if I miss my implementation date?
IRAS has not stated a penalty on the page we checked. Do not plan on leniency. Confirm your date with the IRAS calculator, start onboarding early and ask your software provider for its timeline.
Checked 30 October 2026.
Curious whether Marketing agents fits your business? Talk to KYN on WhatsApp — no forms, just a conversation.
