Singapore InvoiceNow: Peppol E-Invoicing & the IRAS GST Rollout

What is InvoiceNow?

InvoiceNow is Singapore's nationwide e-invoicing network, built on the international Peppol standard and managed by IMDA, Singapore's Peppol Authority. Businesses use it to send and receive invoices as structured data, system to system. Under IRAS's GST InvoiceNow Requirement, GST-registered businesses must also submit invoice data to IRAS through it, phased in between 2025 and 2031.

That is two things under one name, and most confusion about InvoiceNow comes from mixing them up. The network has existed since IMDA introduced it in 2019. The GST InvoiceNow Requirement is newer: a joint IRAS and IMDA initiative that turns the network into the channel for tax data. This page explains both, says plainly who has to use InvoiceNow and when, and answers the four practical questions that follow: what an InvoiceNow invoice carries, what changes when you receive invoices through it, how to check whether a company is on it, and how to connect.

If the underlying network is unfamiliar, what a Peppol Access Point is covers the four-corner model InvoiceNow runs on. Three related questions have pages of their own, and this guide links to each at the point it comes up rather than retelling it:

• "Is my accounting system ready?" — what an InvoiceNow-ready ERP is, with six checks to run against your own installation.
• "How does the tax authority get the data?" — how invoice data reaches IRAS through InvoiceNow, corner by corner.
• "Which provider should we use?" — how to choose an InvoiceNow solution provider, covering IMDA's two published lists.

If you are past the rules and comparing Peppol e-invoicing for Singapore, Singapore e-invoicing sets out what GoRoute connects and how.

Who has to use InvoiceNow, and from when?

Every GST-registered business in Singapore, apart from two excluded groups, will have to submit invoice data to IRAS through InvoiceNow by 1 April 2031. The requirement already applies to new voluntary GST registrants. Existing registrants join in four turnover bands from 1 April 2028, smallest first.

IRAS publishes the schedule on its GST InvoiceNow Requirement page, last updated 8 October 2026:

Two points in that table are easy to misread.

• The first two phases are about how you register, not how big you are. A business that registers voluntarily is in from day one of its registration. A business that registers because it has to (compulsory registration) joins only from April 2028.
• The smallest existing businesses go first. IRAS's FAQ explains why: smaller businesses can mostly use off-the-shelf InvoiceNow-Ready software with little cost or effort, while larger businesses need time to fit the change into their enterprise system refresh cycles.

How is your phase worked out?

Your phase depends on your total annual supplies: the value of your standard-rated, zero-rated and exempt supplies, which is Box 4 of the GST return, across all prescribed accounting periods that end in calendar year 2025. If your accounting periods do not follow the calendar year, the 12 months you count shift with them. IRAS's FAQ for the GST InvoiceNow Requirement gives the exact windows. For example, periods ending in January, April, July and October count November 2024 to October 2025.

You do not have to work it out alone. IRAS says it has written to businesses that were registered for GST before 2026 with their mandatory InvoiceNow implementation date. It also publishes an implementation date calculator on the same page. A business with no GST return for a period ending in 2025 will be told its date later.

Who is excluded?

IRAS names two groups that do not have to comply:

• Overseas entities, including overseas vendors registered under the Overseas Vendor Registration regime.
• Businesses that are liable to register for GST wholly because of the reverse charge.

The second exclusion is narrow. IRAS's FAQ is explicit that a business registered under the normal rules that also makes reverse-charge transactions is still in scope. The same FAQ also rules out three exemption requests that come up often. A business that supplies only related entities, a small or low-volume business, and a business that makes only zero-rated or exempt supplies all still have to comply. They still claim input tax on purchases, and that claim needs the data.

What is not settled yet

The phases from 2028 are published, but not yet in law. IRAS's e-Tax Guide, Adopting GST InvoiceNow Requirement for GST-registered Businesses (second edition, 9 March 2026), says the legislative amendments for the remaining GST-registered businesses "will be enacted at a later date". The dates are IRAS's stated plan, and the legal text has not been published. Confirm your own date with IRAS rather than with any provider's summary, this one included.

Can you start before your phase?

Yes, and IRAS encourages it. A business not yet in a mandatory phase can switch on the GST InvoiceNow submission feature in its software and start sending data early. Until it does, the Peppol invoices it sends still reach its customers, but no copy goes to IRAS. A test environment has been open since September 2024, so providers and businesses can test the connection to IRAS before their date.

Is there support for getting connected?

IRAS lists three grants, with eligibility set by IMDA on its InvoiceNow grants page:

• GST InvoiceNow Transition Grant, S$1,000, for businesses with annual supplies of S$4 million or less.
• GST InvoiceNow Transition Grant, S$5,000, for businesses with annual supplies above S$4 million.
• InvoiceNow Queen Bee Grant, S$25,000, for businesses with annual turnover above S$4 million.

Free-of-charge InvoiceNow-Ready solution packages are available up to 31 March 2031. The current list runs to 31 March 2027, and IRAS says the list for April 2027 onwards will be published later.

How is InvoiceNow different from the GST InvoiceNow Requirement?

InvoiceNow is the network; the GST InvoiceNow Requirement is the tax rule that uses it. The network moves invoices between businesses. The requirement obliges GST-registered businesses to send IRAS a copy of their invoice data over that same network.

IRAS's e-Tax Guide describes the network like this. InvoiceNow launched in 2019 as a nationwide e-invoicing network based on Peppol. It is managed by IMDA, which is appointed as Singapore's Peppol Authority. Its aim is to connect all active businesses so invoices travel in a standard digital format from one finance system to another.

The requirement adds IRAS to that picture. In a normal Peppol exchange there are four corners: the supplier, the supplier's access point, the customer's access point and the customer. IRAS is connected to the network as a fifth corner. Once a business switches on the submission feature, IRAS receives a copy of the invoice data whenever the business issues or receives an invoice through InvoiceNow, or records one in its InvoiceNow-Ready software.

So a business can be on InvoiceNow without being under the requirement: it sends and receives Peppol invoices, and IRAS gets nothing until the feature is on. Under the requirement, it must also report the invoices that never travel over the network, such as paper or PDF invoices to customers who are not connected. How those different paths reach IRAS, and what travels in each, is covered in how invoice data reaches IRAS through InvoiceNow, which also answers whether this makes Singapore a clearance regime. Oman adds a fifth corner for its tax authority too; the Fawtara five-corner model explains how that one works.

What does an InvoiceNow invoice carry?

An InvoiceNow invoice is a Peppol invoice in Singapore's PINT-SG format. It identifies both parties by Peppol IDs built from their UEN, the company's Unique Entity Number. It carries the GST detail IRAS needs line by line: a GST category code and rate on every line, GST subtotals by category, and totals with and without GST.

The format: PINT-SG

Invoices on InvoiceNow are exchanged as XML in a common Peppol format. The original format was Singapore's profile of Peppol BIS Billing 3.0. According to IRAS's e-Tax Guide, an upgrade called the Singapore Peppol International (PINT-SG) Specification was launched in February 2024. It is built for smoother cross-border exchange, and IRAS names it the base data format for the GST InvoiceNow Requirement. Your software normally fills in the format identifiers, but you will see them in the files. PINT-SG invoices declare urn:peppol:pint:billing-1@sg-1 as their specification. GST tax invoices use a dedicated LocalTaxInvoice variant of it.

That makes "InvoiceNow versus Peppol BIS" a false choice. InvoiceNow is the national programme and network. PINT-SG, and the older SG Peppol BIS it replaces, is the content standard the invoices are written in. The wider relationship between the two Peppol formats is explained in Peppol BIS versus PINT.

The identifiers: UEN and Peppol ID

Every business on InvoiceNow has a Peppol ID, which IRAS defines as the unique address that lets it receive business messages such as e-invoices over the network. For a Singapore entity, the Peppol ID is registered under its UEN. In the worked examples in IRAS's e-Tax Guide, a supplier with UEN 202012345M has the Peppol ID SGUEN202012345M under identifier scheme 0195. The UEN is also carried as its own field, and the supplier's GST registration number appears separately.

The mandatory data elements

IRAS's e-Tax Guide sets out the mandatory data elements that must be present and accurate in invoice data sent to IRAS. They follow the existing content rules for a tax invoice under the GST (General) Regulations. In plain terms, an invoice must carry:

• Supplier details: Peppol ID and scheme, UEN, GST registration number, name, and address (first line, postal code, country code).
• Customer details: Peppol ID and scheme, UEN, name, and address.
• Document details: format and profile identifiers, a unique document ID (Doc UUID), invoice number, issue date, invoice type (invoice or credit note) and currency.
• Line details: line number, item name, quantity, unit, net price, line net amount, and a GST category code, rate and tax scheme on every line.
• Totals: GST subtotals by category (taxable amount, tax amount, category code and rate), the sum of line amounts, total GST, totals with and without GST, and the amount due.

Two practical consequences follow. First, you must collect your customers' UENs, names and addresses even for customers who are not on InvoiceNow. An overseas customer is identified by its overseas business registration number, and an individual by "NA". Second, if your system uses its own tax codes, they must be mapped to IRAS's GST category codes before data is submitted. You can keep your internal codes. Whether a given accounting system can do all of this is the subject of what an InvoiceNow-ready ERP is. The validation failures that most often stop a Peppol invoice anywhere are covered in validation errors you can prevent.

What changes when you receive invoices through InvoiceNow?

When a supplier sends you an invoice through InvoiceNow, it arrives in your accounting system as structured data, not as a PDF to re-key. Once your phase applies, you must also submit purchase invoice data to IRAS for the purchases you claim input tax on. Being able to receive is the half of InvoiceNow that most businesses meet first, because a supplier on the network can only send you a Peppol invoice if you are on it too.

Receiving replaces re-keying

IRAS's e-Tax Guide is direct on this: sending and receiving PDF invoices by email is not e-invoicing. A customer who receives a PDF still has to type its details into its own system. An invoice sent through InvoiceNow lands in the customer's accounting system without anyone re-keying it. To receive at all, you need a Peppol ID registered in the SG Peppol Directory, so suppliers can find you.

A Peppol invoice is a valid tax invoice

A Peppol invoice received through InvoiceNow does not carry the words "Tax Invoice". IRAS says it will still accept it as a valid tax invoice to support an input tax claim, as long as it holds all the other contents that Regulation 11 of the GST (General) Regulations requires and the normal input tax conditions are met. Invoices you receive outside the network work the other way. The paper or PDF original remains the source document, and it must show the words "Tax Invoice".

Purchases are in scope, not only sales

Under the requirement, IRAS expects invoice data for standard-rated and zero-rated purchases, as well as supplies. IRAS's FAQ explains why, even though the supplier has already sent its own copy. Your purchase data substantiates the input tax you claim, and it carries information the supplier's copy does not, such as the amount of input tax you are claiming. A purchase on which you choose not to claim input tax is outside the requirement, although you may submit it under category code "OP" if that is simpler.

Rejecting a supplier's invoice

If you reject an invoice that arrived over InvoiceNow, IRAS already holds the supplier's copy. It is sent whether you accept the invoice or not. IRAS's FAQ sets out how to correct it. The supplier either issues a credit note through the network or, where the change does not affect the amount, resubmits a revised invoice under the original document ID. You submit no purchase data for the rejected invoice, only for the corrected one.

How do you check whether a company is on InvoiceNow?

Search the SG Peppol Directory. IRAS describes it as the facility for finding Singapore businesses registered on the InvoiceNow network, and the place to look up a customer's Peppol ID before you invoice it. A business appears there once its solution provider or access point has registered its Peppol ID and updated its details in the Service Metadata Publisher (SMP), the register the network uses to find each business.

What you do next depends on the answer:

• The company is listed. You can send it a Peppol invoice through the network using its Peppol ID. Once you are under the requirement, IRAS receives a copy automatically.
• The company is not listed. You invoice it the way you do today, by paper or PDF. Once you are under the requirement, that invoice's data still has to reach IRAS. It is recorded in your InvoiceNow-Ready software and submitted from there, a path explained in how invoice data reaches IRAS through InvoiceNow.
• The company is outside Singapore. The SG Peppol Directory covers Singapore registrations. Peppol participants in other countries are published through the network's global Peppol Directory, and an invoice to them goes through the same access-point network.

Checking matters before you invoice, not after. A Peppol invoice sent to a business that is not registered has nowhere to go. And a customer who joined the network last month can now take your invoices as data.

How do you connect to InvoiceNow?

Choose your route by the software you already run. Off-the-shelf accounting software connects through an InvoiceNow-Ready Solution Provider. An in-house enterprise system connects through an IMDA-accredited Access Point Provider. Either way, you end with a Peppol ID and the GST submission feature switched on.

IRAS's GST InvoiceNow Requirement page sets out both routes:

IRAS says onboarding can take as little as three months, and most businesses finish within a year, depending on readiness and system set-up. For in-house systems, the e-Tax Guide advises allowing three to twelve months for the connection to IRAS. Count that time back from your phase date, not forward from the day you start looking.

Which provider to choose, how to check a provider against IMDA's two published lists, and what to ask before signing are covered in how to choose an InvoiceNow solution provider. Whether your existing ERP can be connected without a rebuild is covered in what an InvoiceNow-ready ERP is.

Singapore in the Asia-Pacific picture

Singapore is one of a growing group of Peppol jurisdictions in the region. The others include Japan's PINT JP, Australia's rollout, Malaysia's MyInvois and the UAE's PINT AE work. Trading across them means several profiles and reporting layers at once. That is the case for a single multi-country integration. The full calendar is in the e-invoicing mandates 2026 tracker.

How GoRoute helps

GoRoute (POP000991) is a certified Peppol Access Point and SMP. Because InvoiceNow is Peppol, the same integration that reaches European and other Asia-Pacific participants applies in Singapore. You map your data once, validate it before sending, and exchange it over the network through one REST API, with Singapore handled as part of a wider programme rather than as a one-off connector. Incoming documents arrive the same way; e-invoice receiving explains how GoRoute delivers what suppliers send you.

• Talk it through: book a demo and we will walk through your Singapore set-up with you.
• Singapore specifics: Singapore e-invoicing covers what GoRoute connects and what to ask any provider.
• See it first: the video tutorials show ERP connections in practice, and the developer documentation covers the API.
• Read next: how invoice data reaches IRAS through InvoiceNow.

This page does not cover penalties for non-compliance. For those, and for anything about your own business's date, IRAS's own pages are the authority.

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Sources, read on 11 October 2026: IRAS — GST InvoiceNow Requirement (last updated 8 October 2026), for the phase table, exclusions, the onboarding routes and timing, grants, free-of-charge packages and the scope of invoice data; IRAS e-Tax Guide — Adopting GST InvoiceNow Requirement for GST-registered Businesses, second edition, 9 March 2026, for the definitions, the 2019 launch, IMDA's role, PINT-SG, the fifth corner, the mandatory data elements, the Peppol ID examples and the tax-invoice rule; IRAS — Frequently Asked Questions for GST InvoiceNow Requirement, version 23 September 2026, for phase calculation, early adoption, the test environment, purchase data and rejected invoices; IMDA — InvoiceNow; SG Peppol Directory; Peppol / OpenPeppol.