Briefing document & Podcast: Singapore’s E-Invoicing & E-Reporting Mandate (InvoiceNow)

1. Scope of the Mandate
   Singapore’s InvoiceNow system mandates that GST-registered businesses must transmit their invoice data electronically to the tax authority (IRAS) via the national e-invoicing network. This requirement applies broadly to nearly all transactions subject to GST, with only a few specific exceptions: [iras.gov.sg], [imda.gov.sg]

• Domestic B2B (Business-to-Business) and B2C (Business-to-Consumer) Supplies: All standard-rated sales of goods and services within Singapore (B2B and B2C) must be reported through InvoiceNow. This includes invoices for supplies subject to 8% GST (standard-rated) and also zero-rated supplies (e.g. exports of goods and qualifying international services). Zero-rated outward supplies (exports) are in scope and must be transmitted via InvoiceNow, since they are reportable in the GST return. Domestic B2G (Business-to-Government) invoices are not yet separately mandated, but businesses can (and many already do) use InvoiceNow for invoicing government agencies (several public bodies in Singapore accept Peppol e-invoices). A formal B2G mandate is expected in the future, aligning with Singapore’s goal of fully digital procurement. [ey.com] [vatupdate.com]
• Cross-Border Transactions (Imports, Exports, Intra-Community Supplies): Exports from Singapore (cross-border B2B or B2C sales) are zero-rated but are within the e-invoicing mandate – such invoices must be transmitted to IRAS via InvoiceNow just like domestic sales. Imports into Singapore are handled via customs import permits rather than sales invoices, so those are excluded from InvoiceNow reporting. (Import GST is paid through customs mechanisms, not supplier invoices.) Likewise, Singapore is not part of the EU, so EU intra-community acquisitions/supplies and EU “triangulation” scenarios do not directly apply. Any cross-border supply involving Singapore will simply be treated as an export or import: Singapore exports (outbound international B2B/B2C supplies) are reported as zero-rated invoices via InvoiceNow, while imports into Singapore are outside the e-invoicing system and instead handled through import declarations and reverse charge if applicable. [vatupdate.com] [ey.com]
• Self-Billing: Self-billed invoices (buyer-issued tax invoices) are permitted in Singapore under strict conditions. Businesses can engage in self-billing only if both parties are GST-registered and have a prior agreement approved by the Comptroller of GST (IRAS). Under GST regulations, a self-billed invoice must clearly be marked “Buyer Created Tax Invoice – Approved by Comptroller of GST” in place of the normal “Tax Invoice” title. It also must state that “The tax shown is [the supplier’s] output tax due to the Comptroller”, to remind the supplier of their obligation to account for that GST. Self-billing invoices are in scope of the e-invoicing mandate – however, by nature they cannot be exchanged via the standard buyer-supplier Peppol flow. Instead, the buying customer (who issues the self-billed invoice) must transmit the invoice data to IRAS via InvoiceNow as a “solution-extracted” report (with IRAS as the recipient). The selling supplier, if also using InvoiceNow-ready software, should likewise submit the corresponding data from its records to IRAS to ensure consistency. Buyer-side validation: The self-billing arrangement requires the buyer to periodically verify the supplier’s GST registration status and maintain a valid self-billing agreement. Content-wise, self-billed invoices must contain all usual mandatory fields and explicitly be labeled as self-billed (as noted above). These invoices are subject to the same transmission requirements – i.e. they must be reported through the InvoiceNow system – but are issued outside the standard Peppol buyer-supplier loop due to the reversed roles of issuer and recipient. [assist.biz] [iras.gov.sg]
• Triangulation and Chain Transactions: Singapore’s GST system does not have a special “triangulation” simplification as in the EU. If multiple parties are involved in a supply chain, each taxable supply made by a GST-registered entity in Singapore is treated as a normal supply and requires a tax invoice (and hence e-invoice transmission) if it is a standard-rated or zero-rated sale. There is no special exemption for multi-party chain transactions; each leg that is a taxable supply in Singapore must be invoiced and e-reported in the normal way. (For example, in a drop-shipment scenario with an overseas manufacturer, a local intermediary, and a local buyer, the local intermediary’s sale to the buyer is a standard-rated supply that would fall under InvoiceNow reporting.) In essence, all B2B/B2C supplies by Singapore GST-registered businesses are covered, even if they form part of a larger international chain transaction. The only exclusions would be those supplies already outside the GST net (e.g. out-of-scope or exempt transactions – see below).
• Special VAT/GST Regimes: Most special GST schemes or regimes do not remove the requirement to transmit invoice data, though the invoice content and reporting codes may differ for such scenarios. For example, under the Gross Margin Scheme (GMS) for second-hand goods, a qualifying tax invoice must state “Goods are sold under the Gross Margin Scheme – no GST to be charged”, etc., and such invoices still have to be reported via InvoiceNow (with special GST Category codes indicating no tax was charged). Another example is the Approved Tenanted Residential Property (ATR) scheme (lease of residential property is exempt but owner-landlords under ATR can issue invoices showing “GST not chargeable by virtue of ATR”); these invoices would likewise be transmitted through InvoiceNow even though the supply is exempt. Customer accounting (reverse charge for prescribed goods) is a domestic reverse-charge mechanism for certain local B2B supplies (e.g. high-value electronic goods) – such customer-accounted invoices also must be reported via InvoiceNow, with the supplier’s transmitted invoice marked with special codes indicating customer accounting, and the customer’s corresponding purchase report marked with the reverse-charge code and GST due. In general, zero-rated supplies and many exempt supplies are within scope of e-invoicing, while purely out-of-scope items or internal transfers are not. Key excluded categories include: [iras.gov.sg], [iras.gov.sg] [ey.com]
  • Deemed supplies (e.g. free samples, private use of business assets) – no actual tax invoice is issued, so these are not transmitted. [ey.com]
  • Supplies under the Reverse Charge (RC) regime – e.g. imported services where the local business must self-account for GST. Reverse-charged supplies and purchases are excluded from InvoiceNow, since the “supplier” is overseas and not in the network. (The GST on those is accounted via the GST F5 return rather than an e-invoice.) [ey.com]
  • Exempt financial services and sale of digital payment tokens – these are exempt supplies that do not require a tax invoice, thus no e-invoice transmission is needed for fully exempt financial services. [vatupdate.com], [ey.com]
  • Out-of-scope transactions and internal transfers – e.g. goods moved between a head office and branch or consignment stock movements that are not “supplies” for GST purposes do not require e-invoice reporting. [ey.com]

In summary, nearly all taxable supplies (standard-rated or zero-rated, B2B or B2C, domestic or cross-border) made by a GST-registered business must be captured via the InvoiceNow system and transmitted to IRAS. Only a narrow set of transactions – such as reverse-charge items, purely exempt supplies like financial services, non-taxable disbursements, deemed supplies without an invoice, and similar out-of-scope activities – are carved out from the e-invoicing mandate. [vatupdate.com], [ey.com]

2. Taxable Persons in Scope
   All GST-registered persons in Singapore are within the scope of the e-invoicing mandate, with limited exceptions. The requirement currently focuses on newly GST-registered businesses and will expand to cover all GST-registered businesses in phases (detailed in section 3). In practical terms, any person or entity that is registered for GST – whether a locally established business or a foreign company with Singapore GST registration – must eventually comply. This includes companies, partnerships, and sole proprietors, as well as organizations that may not have a physical presence in Singapore but are GST-registered (e.g. via local agents). Key points regarding persons in scope: [iras.gov.sg], [imda.gov.sg]

• Established Local Entities: All Singapore-based businesses that are registered for GST must adopt e-invoicing per the timeline. This covers large companies, SMEs, sole proprietorships, partnerships, and organizations across all sectors. There is no general turnover-based exemption once the system is fully phased in – even very small GST-registered businesses will have to comply (though smaller businesses are scheduled in later phases, see section 3). [iras.gov.sg]
• Non-Established Entities and Overseas Vendors: Foreign businesses that are GST-registered in Singapore (for example, those with a local branch or those that have opted for local GST registration) are subject to the e-invoice mandate as well. However, two categories of GST registrants are explicitly exempted (at least for now) from the InvoiceNow requirement: [iras.gov.sg], [ey.com]
  • Overseas Vendor Registrants (OVR businesses): These are foreign suppliers of digital services or low-value goods who register under simplified “pay-only” GST schemes. Such overseas vendors do not have to adopt e-invoicing for their supplies to Singapore consumers. (These B2C supplies are handled via GST returns, not individual invoices, so IRAS has excluded overseas e-commerce vendors from InvoiceNow.) [iras.gov.sg]
  • Reverse-Charge Only Businesses: Businesses that registered for GST solely due to the reverse charge (typically financial institutions or importers of services who must self-account for GST on imported services) are also excluded from the e-invoicing mandate. Since such entities are not making taxable outward supplies (their GST registration is only to account for GST on imports), IRAS has exempted them from InvoiceNow. [iras.gov.sg]
• Voluntary vs. Compulsory Registrants: The initial phases (through 2026) focus on voluntarily registered businesses (those that chose to register for GST despite being below the turnover threshold). From 2028 onward, newly compulsory registrants (businesses that are required to register due to exceeding the S$1 million revenue threshold) will also be brought in, followed by all remaining GST-registered businesses. Thus, being “in scope” is determined by GST registration status and the phase-in schedule – not by entity type or industry (except for the specific exclusions above). [vatupdate.com] [iras.gov.sg]
• Group Registrations and Divisional Registrations: If a GST group or divisional registration includes members that are in scope, those members will need to comply. For GST group registrations, IRAS has indicated that the phased timeline for existing businesses will apply to the entire group at once (to be confirmed by mid-2026). Notably, if a new GST-registered subsidiary joins an existing GST group, its e-invoicing requirement will align with the group’s phase (i.e. slightly later) rather than immediately at registration. Excluded businesses (like an OVR entity) that are part of a GST group do not have to transmit their own invoices; however, other group members still do, and the group may voluntarily transmit all invoices for completeness. [imda.gov.sg], [imda.gov.sg] [iras.gov.sg]
• Optional Early Adoption: Although not required until their phase, any GST-registered business may opt to start e-invoicing voluntarily before it becomes mandatory. IRAS has strongly encouraged early adoption to ensure systems are working well ahead of deadlines. Many companies have already joined the network as early adopters, gaining experience with the process before the mandate kicks in. (As of early 2026, over 63,000 businesses were already on the InvoiceNow network, even though the mandate for most businesses had not yet begun.) This voluntary participation is facilitated by government incentives (see section 12 on SME impact) to minimize barriers for early movers. [iras.gov.sg] [sg.news.yahoo.com]

3. Implementation Timeline
   The e-invoicing/e-reporting mandate is being rolled out in stages from 2025 to 2031, giving businesses time to prepare and ensuring software and infrastructure are in place. The official timeline (announced by IRAS and reaffirmed in the Feb 2026 Committee of Supply parliamentary session) is as follows: [iras.gov.sg] [iras.gov.sg], [imda.gov.sg]

• 1 May 2025 – Soft Launch (Voluntary Phase): Start of voluntary adoption. From this date, any GST-registered business can begin transmitting e-invoices to IRAS via InvoiceNow on a voluntary basis. Early adopters are encouraged with incentives such as free access to InvoiceNow solutions and grants (see section 12) to test and familiarize themselves with the system ahead of mandatory deadlines. [vatupdate.com], [dtl.sg]
• *1 November 2025 – Phase 1 Mandate begins: Newly-incorporated voluntary GST registrants. Any business that incorporates and then voluntarily registers for GST within 6 months of incorporation must, from this date, use an InvoiceNow-compatible solution and begin transmitting its invoice data upon registration. In practice, this means new startups opting into GST in late 2025 need to obtain a Peppol InvoiceNow ID and have an e-invoicing system in place as a condition of registration. IRAS coordinates this with the GST registration process (applicants will be instructed to comply before the GST number is activated). [iras.gov.sg] [vatupdate.com]
• *1 April 2026 – Phase 2: All new voluntary GST registrants. From this date, any business applying for voluntary GST registration (regardless of age or structure) must commit to InvoiceNow reporting as a registration condition. In short, after 1 Apr 2026 no voluntarily registered GST business can remain on paper invoicing – they must e-invoice from day one of their GST registration. This will expand the mandate to a larger pool of SMEs and other entities entering the GST system. IRAS has been actively informing and preparing would-be registrants of this requirement in advance, to ensure a smooth transition for new filers. [iras.gov.sg] [vatupdate.com]
• *1 April 2028 – Phase 3: New compulsory registrants and smallest existing businesses. All newly GST-registered businesses under compulsory registration (i.e. those exceeding the S$1M turnover threshold) must use InvoiceNow from their registration date. In addition, all existing GST-registered businesses with annual taxable turnover not exceeding S$200,000 must commence e-invoicing by 1 Apr 2028. This will draw in thousands of smaller enterprises (many of which are voluntarily registered for GST) into the mandate. Notably, the government chose to onboard the smallest companies earlier than the largest, so as to “support them better in their transition” – smaller firms often use off-the-shelf software that can be updated more quickly, whereas big companies may need more time to upgrade complex systems. [iras.gov.sg] [imda.gov.sg], [imda.gov.sg]
• *1 April 2029 – Phase 4: Existing GST-registered businesses up to S$1M annual supplies. By this date, all GST-registered businesses with annual sales of S$1,000,000 or below must be using InvoiceNow (this covers the bulk of SMEs). [iras.gov.sg]
• *1 April 2030 – Phase 5: Existing businesses up to S$4M annual supplies. By April 2030, medium-sized enterprises fall in line: all GST-registered companies with annual supplies not more than S$4,000,000 are mandated to transmit e-invoices. [iras.gov.sg]
• *1 April 2031 – Phase 6 (Final): Largest businesses above S$4M. By this date, every remaining GST-registered business – including those with annual supplies above S$4 million – comes into the InvoiceNow regime. At this point (April 2031), e-invoicing and e-reporting will be fully mandatory for 100% of GST registrants in Singapore. [iras.gov.sg]

Each phase’s cutoff is based on the total value of supplies in calendar year 2025 (for existing businesses) as calculated by IRAS. IRAS has promised to notify all existing GST-registered taxpayers by mid-2026 of their assigned “go-live” date for the mandate. In the meantime, companies can use a provided Excel “InvoiceNow Implementation Date Calculator” to self-assess which phase they fall into. [iras.gov.sg]

It’s important to note that these dates refer to the requirement to start e-invoicing. Once your mandated start date arrives, all in-scope invoices issued on or after that date must be transmitted via InvoiceNow. There is no separate “grace period” beyond the phased schedule itself. However, IRAS has indicated it will adopt a “calibrated lenient approach” in the initial stages, focusing on education and allowing time to resolve teething issues for compliant taxpayers. This means that in the early phase of the mandate, businesses making genuine efforts to comply may be given remediation opportunities rather than immediate penalties for inadvertent errors. Nonetheless, businesses are expected to be ready by their phase’s deadline and to begin e-invoicing from day one, as failure to do so will constitute non-compliance (see section 10 on penalties). Different sectors do not have distinct timelines; the schedule is solely based on registration type and turnover, as above. [vatupdate.com]

4. Technical & Functional Requirements
   InvoiceNow utilizes a standardized e-invoice format and well-defined data requirements to ensure interoperability and tax compliance. Key technical and functional aspects include:

• E-Invoice Format and Standards: Singapore’s e-invoices are transmitted in structured XML format following the Peppol international standard. Initially, the system supported the Peppol BIS Billing 3.0 format; more recently, Singapore introduced a simplified localization called “PINT-SG” (Peppol InvoiceNow Template – Singapore). Both formats are currently accepted, but from 2025 onward PINT-SG is expected to be the required standard for InvoiceNow transmissions. The Peppol-based format ensures that invoices meet a common standard (aligned with the European Norm 16931) for content and structure. This allows invoices to flow between different finance systems via the network without manual intervention. (Notably, PDFs or unstructured formats are not considered e-invoices and will not satisfy the requirement.) InvoiceNow transactions include an electronic envelope (the “Service Metadata Publisher” header) with addressing information (the buyer’s and seller’s Peppol IDs) and the core XML invoice complying with the PINT-SG data schema. [vatupdate.com], [vatupdate.com] [vatupdate.com] [cleartax.com]
• Mandatory Data Fields: All invoice data sent via InvoiceNow must include a comprehensive set of Mandatory Data Elements (MDEs) as specified by IRAS. In essence, the e-invoice contains all the information that a full GST tax invoice would require – but in structured data form. Key required fields include: [vatupdate.com], [cleartax.com]
  • Supplier and Customer Identification: Legal names, addresses, and GST registration numbers (the GST Registration Number is typically the business’s UEN – Unique Entity Number – suffixed with a GST suffix). The Peppol “Buyer ID” and “Seller ID” in the invoice must be the parties’ identifiers (usually their UENs) and their GST registration numbers if they are registered. [vatupdate.com], [vatupdate.com] [iras.gov.sg]
  • Invoice Details: A unique invoice number; the invoice date (time of issue); and a universally unique identifier (UUID) for the invoice document for traceability. Debit notes and credit notes are treated as distinct invoice types but use the same data structure, with fields linking them to the original invoice reference number if applicable. [vatupdate.com], [vatupdate.com]
  • Line-Item Details: Description of each good or service, quantity, unit price, and line amount. Each line must also carry a GST category code indicating its tax treatment (e.g. standard-rated “SR” for 8% GST supplies, “ZR” for zero-rated exports, “ES” for exempt supplies, etc.). IRAS provides a list of accepted GST codes (e.g. “SR”, “ZR”, “ES”, “DS” for deemed supplies, “OS” for out-of-scope, “TX-CA” for customer-accounted transactions, etc.) in Annex E of the e-Tax Guide. Businesses need to map their internal tax codes to these prescribed codes. [vatupdate.com] [iras.gov.sg], [iras.gov.sg]
  • Tax Amounts and Totals: The GST amount for each taxable line (if any) and the total GST charged on the invoice must be included, along with gross amounts (subtotal and total payable). The invoice must also indicate the applicable GST rate for each line or category of supply – typically 8% for standard-rated items (note: GST in Singapore rose from 7% to 8% on 1 Jan 2023, and to 9% from 2024). If a line is zero-rated or exempt, the rate is “0” but the correct code (ZR, ES, etc.) must still be provided. [vatupdate.com], [vatupdate.com] [iras.gov.sg], [iras.gov.sg]
  • Currency and Foreign Amounts: Invoices can be issued in any currency, but if a foreign currency is used, the invoice data must include the SGD-equivalent amounts for the taxable amount and GST, using an acceptable exchange rate (e.g. from a bank or IRAS’s published rates). The currency code should be specified (e.g. “USD”, “EUR”) in the data. [vatupdate.com]
  • Special Invoice Indicators: The format supports flags or notes to handle special cases. For instance, “aggregated” invoices (summaries of many small cash sales or POS transactions – see section 6) can be marked accordingly (often by entering “PointOfSale” or “Aggregated” in a designated field). Similarly, certain prescribed statements (like those for self-billed invoices, customer accounting, or GST schemes) should be included in a “Invoice Note” field in the e-invoice to mirror the required text on a paper invoice. The InvoiceNow schema provides specific fields for these notes and references. [vatupdate.com] [iras.gov.sg]

Validation: E-invoices are subject to automated validation by the Access Point and IRAS systems. Submissions with missing mandatory fields or incorrect data formats will be rejected and need to be corrected by the business. This ensures data integrity and that only compliant invoices are considered successfully transmitted. Businesses should therefore configure their software to capture all required data and use testing/sandbox services if available to validate file formats prior to live submission. [cleartax.com], [cleartax.com]

• E-Reporting via InvoiceNow: In the Singapore model, “e-reporting” is achieved through the same technical mechanism as e-invoicing. If an invoice is issued to a counterparty who is not on the InvoiceNow network (for example, a consumer or an overseas customer), the supplier still must transmit the invoice data to IRAS via the network – essentially this is electronic reporting of the transaction to IRAS. In such cases, the business’s software will send the invoice data through its Access Point with IRAS designated as the receiver. The data payload and format remain the same as a normal e-invoice; the only difference is that the buyer’s Peppol ID might be a placeholder or the invoice is flagged as a report-only submission. IRAS refers to an e-invoice sent only to IRAS (and not to a buyer) as a “solution-extracted invoice” submission. [vatupdate.com] [iras.gov.sg]

Thus, there is no separate “e-reporting file format” – the data model for InvoiceNow covers both scenarios. Every in-scope transaction must result in an XML invoice data transmission: either a Peppol e-invoice (to a buyer that is on the network, with IRAS automatically copied), or a direct InvoiceNow submission to IRAS (if the buyer is offline). In both cases, the same mandatory fields and schema apply. The InvoiceNow Technical Playbook (published by IMDA) details the integration approach for software providers, and IRAS’s e-Tax Guide lists all data elements required. The system is designed to accept up to 10 invoices per submission (or up to 10 MB of data), allowing batched transmissions if needed. [imda.gov.sg], [iras.gov.sg] [vatupdate.com]

• Digital Signatures & Security: Singapore’s e-invoice model does not require taxpayers to digitally sign invoices, unlike some clearance regimes. Instead, the integrity and authenticity of InvoiceNow e-invoices are ensured by the secure Peppol network and Access Point infrastructure. The network uses PKI (Public Key Infrastructure) for channel security, and each Access Point must be accredited by IMDA, ensuring that data is transmitted through trusted nodes. While businesses are free to apply their own electronic seals or signatures on PDF representations of invoices, IRAS does not mandate a specific digital signature on the XML invoice. The focus is on transmitting the data through approved channels, which inherently provides data integrity (along with system audit logs). [vatupdate.com], [vatupdate.com]
• Real-Time vs Batch Processing: Singapore’s approach is often characterized as a “post-audit” continuous reporting model rather than a hard clearance before invoicing. Invoices do not need to be individually approved by IRAS in real time before delivery – as long as they are transmitted by the required deadline (see section 6 on due dates). Businesses can send invoices in real-time (and indeed, if using InvoiceNow to deliver to customers, the transmission to IRAS happens immediately). Alternatively, they may opt to send invoice data in batches (e.g. uploading a day’s or week’s invoices together) using the InvoiceNow APIs – as long as all required data for a given accounting period is received by IRAS by the filing deadline. In practice, many companies will integrate the transmission into their billing cycles for efficiency. IRAS encourages prompt or frequent submission (even though true real-time clearance is not mandated), because early transmission helps identify any issues and can facilitate quicker GST refunds and compliance checks. [vatupdate.com] [vatupdate.com], [imda.gov.sg]

5. Correction of Errors in E-Invoices and E-Reporting
   Despite best efforts, businesses may occasionally need to correct errors in invoices or reported data. Singapore’s framework handles corrections through normal GST credit/debit note processes and return adjustments, rather than a separate “correction report” message. The guiding principle is that errors in issued invoices are rectified by proper credit notes or amended invoices, and any discrepancies in reported data are ultimately resolved via the GST return (or its amendment). Key considerations:

• Correcting an Issued E-Invoice: If a tax invoice has been issued with an error (e.g. wrong amount, tax rate, or customer details), the supplier must issue a GST credit note or debit note according to existing GST rules. The credit note should refer to the original invoice and clearly indicate the adjustment (e.g. the overcharged GST being refunded). Under e-invoicing, the credit note is prepared and transmitted through InvoiceNow just like a regular invoice – it uses the same XML format and includes a reference to the original invoice number it corrects. Once sent via the business’s InvoiceNow solution (or Access Point), IRAS will receive the corrected data automatically, and (if the customer is on InvoiceNow) the customer will also receive the credit note electronically. For example, if an over-billing is discovered, the supplier would issue a credit note for the overcharged amount, and that credit note would be submitted through InvoiceNow so IRAS has a record of the adjustment. If an original invoice was completely wrong and needs cancellation, the business can effectively cancel it by issuing a credit note for the full amount (bringing net to zero) and then issuing a new corrected invoice – both of which would be transmitted to IRAS via InvoiceNow (the credit note to negate the original, and the new invoice with correct details). [support.financio.co], [support.financio.co]
• Resubmitting or Adjusting Reported Data: If an error is discovered in the invoice data after it has been transmitted to IRAS (for instance, an invoice was sent with an error in values or tax coding), the business should first correct it by issuing the appropriate credit note or adjusted invoice as described above. As long as this is done before filing the GST return for that period, the corrected data will be reflected in the reporting for that period. If an error is discovered after the GST F5 return has been filed, the business may need to adjust in the next return or, if the error is above S$5 million or meets other criteria, file a formal GST F7 amendment (as per standard GST error correction rules). Notably, IRAS has indicated that it will not penalize minor discrepancies between InvoiceNow data and the GST return as long as taxpayers maintain proper records and correct any mistakes on a timely basis. In other words, if an invoice was missed or reported incorrectly via InvoiceNow but the GST return itself is correct, or if the mistake is fixed in the next return, IRAS will generally not impose a penalty for such first-time errors provided they are inadvertent and the taxpayer can substantiate the corrections. However, deliberate or reckless omissions in e-reporting would be viewed seriously (on par with misreporting in GST returns). [iras.gov.sg], [iras.gov.sg]
• Notifying IRAS of Errors: There is no separate real-time “error report” form for e-invoicing. Instead, the established GST processes apply. For example, if a business discovers after filing that an earlier InvoiceNow transmission was incorrect (say an invoice was mistakenly not transmitted at all, or transmitted with wrong values that led to an under-declaration of GST), the business should follow GST correction procedures: submit a GST F7 return (Voluntary Disclosure) if required, or adjust the error in the next return if within the allowable threshold (currently S$5,000 for most businesses). The underlying invoices/credit notes should of course be transmitted via InvoiceNow as soon as the mistake is noticed, so IRAS’s records are updated. In summary, correcting an invoice error under InvoiceNow = issuing the necessary correcting document (credit note or amended invoice) + ensuring that document’s data is sent through InvoiceNow. IRAS will then reconcile the updated data with the GST returns. No separate notification to IRAS is needed beyond the normal GST return amendment process, unless the error meets the criteria for a formal F7 amendment (in which case the F7 return should be filed as usual, referencing the error and its correction). [iras.gov.sg]

6. Transmission & Workflow
   Singapore’s e-invoicing model uses a decentralized “network” approach (Peppol 4-corner model) rather than a single government portal, with IRAS receiving invoice data in parallel. Key aspects of how invoices/reports are transmitted and processed include:

• “Five-Corner” Architecture: InvoiceNow is built on the Peppol network, an interoperability framework where accredited private-sector service providers (Access Points) exchange invoices between suppliers and buyers. To use InvoiceNow, a business must either adopt an accounting/ERP software that is an IMDA-accredited “InvoiceNow-ready solution” or connect to the network via a third-party Access Point (AP) provider. Each business obtains a unique Peppol ID (in Singapore, typically derived from its UEN) which serves as its address on the network. When a GST invoice is issued, the software converts it into the Peppol XML format and sends it to the seller’s AP, which in turn routes it to the buyer’s AP using the buyer’s Peppol ID. Simultaneously (or immediately afterward), a copy of the invoice data is delivered to IRAS via the same network, either by CC’ing IRAS as an additional recipient or by the buyer’s AP forwarding the data to IRAS. (In practice, IRAS is identified by a specific Peppol participant code to receive a copy of all InvoiceNow transactions.) This way, IRAS receives the invoice information in real time or near-real time, directly from the transaction flow. Importantly, there is no need for suppliers to separately log into a government portal to “upload” invoices; the data is sent automatically through the APs once the invoice is issued in the business’s system. [vatupdate.com] [cleartax.com], [cleartax.com] [cleartax.com]
• Central Platform vs Intermediaries: Singapore’s approach leverages private-sector intermediaries rather than a single central government platform. The “clearance” of invoices (i.e. sending data to tax authorities) is embedded into the B2B invoicing process via software. There is no portal where businesses manually enter invoices; instead, IRAS-approved software and networking infrastructure handle the data exchange in the background. All APs must meet IMDA’s technical and security standards, and they deliver invoice data to IRAS through a secure API connection. Thus, while there isn’t one monolithic government platform used by all taxpayers, the result is the same – IRAS receives the data for each invoice, typically within seconds or minutes of its issuance. [vatupdate.com]
• Transmission Deadlines: Businesses are required to transmit each invoice’s data by the time they file the GST return for the period in which the transaction is reported, or by the statutory due date for that return – whichever comes first. In practice, this means the cut-off for e-invoice reporting is aligned with the GST reporting cycle. For example, if a company files quarterly GST returns due on the last day of the month following each quarter, all invoices for Q1 (Jan–Mar) must be transmitted by April 30 when the Q1 GST return is due. There is no strict “real-time within 24 hours” rule, as some countries have; businesses can batch their InvoiceNow submissions as long as everything is submitted by the return deadline. However, waiting until the deadline to push a large batch is discouraged – IRAS recommends more frequent (e.g. “T+1” daily or weekly) submissions to avoid bottlenecks and allow prompt identification of any errors. [vatupdate.com]
  • Periodic Summaries for High-Volume Small Transactions: For very high-frequency, low-value transactions (for instance, retail cash sales or petty cash expenses), IRAS provides a facility to ease reporting. Businesses can aggregate multiple small transactions into a single “consolidated” invoice entry for e-transmission. In practice, this means a retailer could send one summary invoice for, say, total cash sales of the day or week, instead of thousands of individual receipts. The InvoiceNow schema supports marking such entries with an indicator (e.g., “Point-of-Sale” or “aggregated” invoice type) to distinguish them. This approach balances compliance with practicality, ensuring that even B2C retailers without customer-specific invoices can meet the reporting requirement without excessive administrative burden. These summary invoices must be transmitted by the same deadlines (e.g. a March 2026 summary of cash sales would be sent by the April 2026 filing date). [ey.com] [support.financio.co], [support.financio.co]
• Workflow Integration: For most businesses, the process of sending e-invoices/reports will be integrated into their normal billing and accounting workflows. For example, a company using an InvoiceNow-ready accounting system can issue an invoice inside that system and simply check a box or select an option to “Send to IRAS via InvoiceNow”. The software then handles the transmission automatically in the background. Once sent, the system may provide a status update or confirmation (e.g., showing that IRAS successfully received the data). There is no need for separate manual filings of invoice data, as long as the software is properly configured. Businesses with in-house or custom billing systems can achieve the same by working with an Access Point provider to connect their system to the InvoiceNow network via API. [support.financio.co]
• Receiving E-Invoices: One of the benefits of e-invoicing is that it works both ways – businesses can send and receive invoices through the network. If your suppliers are on InvoiceNow, you will start receiving structured e-invoices (XML) in your system instead of paper or email PDF bills. This can streamline accounts payable significantly for B2B transactions. Note that receiving invoices via InvoiceNow is not mandatory – the mandate is on sending data to IRAS – but by 2030, the majority of businesses will be on the network, so receiving electronic invoices will become increasingly common. (In fact, as part of the European “VAT in the Digital Age” proposals, Singapore’s use of Peppol will enable easier exchange of e-invoices with trading partners abroad in the future.) Businesses should ensure their chosen InvoiceNow solution can handle both outbound and inbound e-invoices, even though the law directly concerns outbound reporting. [Articles a…rs exter 1 | Word]

7. Self-Billing
   Self-billed invoicing (where the buyer issues an invoice on behalf of the supplier) is allowed in Singapore under existing GST rules, and the e-invoicing mandate extends to such transactions with certain additional requirements. Key points include:

• Permissibility and Conditions: A self-billing arrangement requires that both the supplier and customer are GST-registered in Singapore and have a prior agreement approved by IRAS’s Comptroller of GST. The customer (buyer) must undertake to issue compliant “buyer-created tax invoices” on the supplier’s behalf, and the supplier agrees not to issue its own invoices for those transactions. The buyer must also periodically confirm the supplier’s GST registration status (since the arrangement must cease if the supplier is no longer GST-registered). These conditions (documented via a self-billing agreement) remain in force under InvoiceNow. [assist.biz]
• Use of E-Invoicing Platform: Self-billed invoices must still be reported through the InvoiceNow system, but the workflow differs because the invoice is created by the buyer. In practice, a self-billing customer will generate the “Buyer Created Tax Invoice” in their accounting system and transmit it via their Access Point directly to IRAS (and optionally to the supplier’s system). IRAS has clarified that self-billing invoices “can only be issued outside the InvoiceNow network” (since the normal Peppol delivery is supplier-to-buyer) and are to be transmitted as “solution-extracted” invoice data to IRAS. In simpler terms: the buyer’s system will send the invoice XML to IRAS over InvoiceNow (fulfilling the e-reporting duty), and if the supplier also uses InvoiceNow, the buyer may simultaneously route the e-invoice to the supplier’s Access Point (so the supplier receives a copy). The supplier, as the legal issuer of the tax invoice for GST purposes (even though it was created by the buyer), must ensure the invoice data they received matches what the buyer issued. If the supplier’s system generates its own record of the self-billed transaction for internal accounting, the supplier’s system should not re-transmit that as a separate invoice to IRAS (to avoid duplication); instead, it should be able to reconcile that record to the buyer’s reported data. [iras.gov.sg] [iras.gov.sg], [iras.gov.sg]
• Invoice Content Requirements: A self-billed invoice must meet all the standard tax invoice requirements and include specific wording. It must be clearly labeled “Buyer Created Tax Invoice – Approved by the Comptroller of GST” (this replaces the usual “Tax Invoice” title). It also must state that “the tax charged is accounted for by the supplier”, typically with a statement such as “The tax shown is your output tax, due to the Comptroller of GST” addressed to the supplier. These phrases are required to be present on the face of the invoice to distinguish it as a self-billed invoice. In the InvoiceNow data, such details are included in the “Invoice Note” field (or equivalent) so that IRAS and the transacting parties are aware of the nature of the invoice. Beyond these specifics, the invoice must contain all the usual fields (invoice number, date, parties’ details, description, values, tax amount, etc.). Credit notes under self-billing (e.g. to adjust or cancel a buyer-created invoice) would also be issued by the customer and must similarly be transmitted via InvoiceNow to IRAS. [iras.gov.sg]
• Buyer’s and Supplier’s Responsibilities: In a self-billing scenario, the buying customer takes on the responsibility of accurate invoice issuance, so the buyer must have robust processes to capture the necessary details and use a compliant e-invoicing solution. The supplier, although not issuing the invoice themselves, is still responsible for reporting the output tax – hence they must ensure the self-billed invoices received from the customer are properly accounted for. There is a risk that the invoice data as recorded in each party’s system could differ (for example, if the supplier’s system auto-generates an internal invoice record for the transaction with a different number or date). IRAS has stated that if a supplier’s internal records (accounts receivable) produce invoice data that doesn’t exactly match the customer’s self-billed invoice data already transmitted to IRAS, the supplier must be able to reconcile and explain any differences and produce the corresponding records if asked. In summary, self-billing is allowed and can continue under InvoiceNow, but both parties must meet the content rules and ensure the invoice information is properly sent to IRAS and recorded on each side. [iras.gov.sg], [iras.gov.sg]

8. Triangulation & Special Scenarios
   Singapore’s e-invoicing mandate encompasses most transaction types, including complex or atypical scenarios, though certain cases require special treatment. Below we address how some special scenarios are handled:

• Triangulation Transactions: Triangulation, in the EU VAT sense (a three-party chain transaction across different jurisdictions, using simplification measures), does not have a direct parallel in Singapore’s GST system. If a Singapore GST-registered business is involved in multi-jurisdictional chain transactions, its obligations under InvoiceNow depend on its role: any taxable supply it makes (as a seller) to a local customer will require an e-invoice to IRAS, while any purchase it makes as a buyer from a foreign supplier has no local invoice to transmit (though the GST on imported goods or services may be accounted via customs documentation or reverse charge, outside of InvoiceNow). In other words, each link of a chain that is a taxable supply by a Singapore GST-registrant must be documented with an e-invoice to IRAS, but there is no special exemption or unique “triangulation” reporting mechanism in Singapore. Standard GST rules and the normal e-invoicing requirements apply. [ey.com]
• Chain or Multiple-Party Transactions: Similarly, for domestic chains involving multiple parties (e.g. a manufacturer selling to a distributor who then sells to a retailer), each B2B sale between GST-registered parties is treated independently for e-invoicing purposes. Each GST-registered seller in the chain must issue a compliant tax invoice to its customer and transmit that invoice via InvoiceNow to IRAS. There is no reduction of scope for multi-step transactions – the presence of an intermediate reseller doesn’t remove the need to e-report the initial sale or the subsequent sale. The final B2C sale in the chain (e.g. retailer to consumer) would also be subject to e-invoice reporting, though as noted in section 6, retailers can send aggregated daily/weekly sales data instead of individual consumer receipts. [ey.com]
• Cross-Border Reverse Charge Scenarios: When a Singapore business imports services that are subject to Reverse Charge (RC) – meaning the Singapore buyer must account for GST – no supplier e-invoice is required to be sent via InvoiceNow, since the overseas supplier isn’t in the system and typically won’t issue a local tax invoice. These transactions are explicitly excluded from the InvoiceNow transmission requirement. Instead, the Singapore business accounts for GST via its GST return (Box 3 + Box 6 in the F5 return) as per normal RC rules. However, if the Singapore business provides a *credit note or internal document to the overseas supplier (or within its group) to adjust the value of an imported service, that document is not a “tax invoice” and does not need to be transmitted (it’s not part of GST reporting to IRAS). In summary, RC-type scenarios involve no InvoiceNow component for the purchase itself – though if the Singapore business on-supplies those imported services locally, that onward supply (if standard-rated) would generate an e-invoice. [ey.com]
• Zero-Rated & Exempt Supplies: As noted earlier, outward zero-rated supplies (exports, international services) are within the e-invoicing scope – they require the same InvoiceNow data transmission, with the GST tax amount as 0 and appropriate GST codes (e.g. “ZR”) used. Exempt supplies have a nuanced treatment: Many exempt supplies do need to be reported via InvoiceNow, but a few are excluded. Specifically, exempt supplies that still require a tax invoice – such as the sale or lease of residential property (which is exempt but normally requires a “tax invoice” for commercial/residential mixed-use properties) or the sale of investment-grade precious metals (GST-exempt) – are included and must be e-reported. On the other hand, “pure” exempt supplies that do not involve a tax invoice (notably most financial services and the sale of digital payment tokens, which are exempt by law without invoice requirements) are excluded from e-invoicing. Those transactions are typically aggregated in GST returns only, with no invoice-level reporting. [vatupdate.com] [ey.com]
• Other Local Schemes (e.g. Tourist Refund Scheme, Bad Debt Relief, etc.): These are handled via the GST return rather than through InvoiceNow. For example, under the Tourist Refund Scheme, retailers already submit tourist refund details to IRAS through a separate system; those aren’t regular B2C tax invoices and are outside InvoiceNow. Bad debt relief or customer accounting adjustments are similarly claimed through GST returns (and supported by credit notes) rather than any special InvoiceNow process. In general, if a transaction or adjustment does not generate a standard invoice/credit note, it’s likely not sent via InvoiceNow (though it still must be documented for GST). For all transactions that do have tax invoices, the rule of thumb is: if it’s reported in the GST return, and you issue a tax invoice for it, that invoice’s data should go through InvoiceNow. [ey.com]

9. Archiving & Retention
   GST-registered businesses must continue to maintain proper records of all invoices and transmissions, even in the e-invoicing era, in accordance with existing record-keeping laws. The move to digital invoicing does not remove record retention obligations; in fact, IRAS explicitly states that businesses must still keep all required records (and file GST returns) as usual, even though invoice data is being submitted electronically. Key points on archiving and retention: [vatupdate.com]

• Retention Period: All GST invoices (whether paper or electronic), credit notes, and related records must be retained for at least 5 years (the standard statutory record retention period for GST in Singapore). This requirement remains unchanged with e-invoicing. Businesses should ensure that their e-invoicing solution either retains copies of sent invoices or that the data is archived in a readable format for at least five years. The 5-year period is counted from the end of the relevant accounting period in which the transaction was made (in line with general tax record rules). Longer retention may be required if an assessment is under dispute or if specifically requested by IRAS.
• Format of Archived Invoices: IRAS’s record-keeping guidelines allow records to be kept electronically, provided they are legible, secure, and capable of being produced on request in a readable format. Invoices transmitted via InvoiceNow will typically be stored as XML data in the business’s accounting system or Access Point archive. It is good practice to also retain human-readable versions (such as a PDF render or printout of the invoice) for ease of reference in audits. The official IRAS e-Tax Guide includes examples of XML invoice data and how it corresponds to human-readable information (see Annexes A, B, C for sample invoice and credit note submissions). Businesses must ensure that the integrity and authenticity of the invoices are preserved in storage – in practical terms, this means safeguarding the electronic records from alteration. Invoices sent through the network are uniquely identified (by invoice number and UUID) and any subsequent modification would require a formal adjustment (credit/debit note), so as long as businesses do not delete or overwrite the original files and only make changes through proper adjustments, integrity is maintained. [iras.gov.sg], [iras.gov.sg]
• Location of Storage: Singapore permits electronic records to be stored overseas (for example, on cloud servers or foreign data centers) as long as they remain accessible to IRAS on demand. Companies using cloud-based InvoiceNow solutions or APs should verify that data is backed up and can be retrieved in a timely manner if an audit arises. IRAS has not mandated local on-premise storage of e-invoices, but taxpayers bear responsibility for ensuring records are available locally when required. Many businesses will rely on their solution providers to store and manage invoice archives. It’s advisable to confirm with your software/solution provider how long they retain transmitted invoices and in what format, to ensure compliance with the 5-year rule.
• Audit Access: IRAS officers may request to see your invoice data and business records during audits or queries, and businesses must be able to provide the information in a usable form. The e-invoices transmitted to IRAS will already be in the tax authority’s systems, but a taxpayer may need to produce records to reconcile any differences or to explain business transactions (including, for example, demonstrating the non-GST nature of excluded transactions). Therefore, maintaining a clear internal archive (with links between your internal records and what was reported via InvoiceNow) is important. IRAS has reassured taxpayers that minor discrepancies between e-invoice data and return figures will not be penalized if records are kept and the differences can be explained (e.g. timing differences, or non-transmitted items like non-GST out-of-scope sales). Nonetheless, as a best practice, businesses should periodically reconcile the total of invoices transmitted to IRAS with the sales/purchase figures in their GST returns to identify any gaps or overlaps, and retain documentation for any unreported items (e.g. purely exempt supplies) in case of questions. [iras.gov.sg], [iras.gov.sg]

10. Penalties & Enforcement
    Non-compliance with the e-invoicing and e-reporting requirements may result in penalties under Singapore’s GST laws. Though IRAS has indicated an initial grace approach (focusing on education over punishment in the early stages), the expectation is that businesses will comply by their mandated start date. Key enforcement points include:

• Denial of GST Registration or Revocation: In the initial phases, a primary enforcement mechanism is tied to GST registration status. New applicants who are required to use InvoiceNow and fail to do so can have their GST registration denied or delayed by IRAS. Likewise, a newly registered business that does not implement e-invoicing as required could even have its GST registration revoked by IRAS. Essentially, adopting InvoiceNow is part of the conditions to be (and remain) GST-registered if you fall in the mandated group. This measure ensures strong compliance from businesses entering the GST system. [vatupdate.com]
• Fines for Failing to Issue/Transmit Invoices: Once the requirement is in full effect, not transmitting a required invoice is an offence equivalent to failing to issue a tax invoice when required by law. Under Section 41 of the GST Act, GST-registered persons must issue tax invoices for their B2B supplies, and a failure to do so can incur a fine of up to S$5,000 for each offence, and/or prosecution. By extension, if a business simply doesn’t use InvoiceNow at all when obligated, they would be failing to issue proper tax invoices (since after their phase-in date, a compliant invoice must be electronic). Thus, a company that does not comply with e-invoicing could face financial penalties. IRAS has not yet published e-invoice-specific penalty tables, but non-compliance will likely be enforced via existing provisions of the GST Act (which impose fines up to $5,000 for omissions or failures with respect to invoices or record-keeping). [straitstimes.com], [straitstimes.com]
• Incorrect or Late Reporting Penalties: If a business neglects to transmit invoices by the due date (e.g. chronically sending data long after the GST return is filed) or submits erroneous invoice data without subsequent correction, IRAS may treat this as a filing offence or failure to keep proper records. Under general GST provisions, failure to keep proper records or to furnish correct returns can attract penalties ranging from fines up to $5,000 (per offence) and a default penalty of $100 per day for continued non-compliance. In more serious cases involving fraudulent evasion of GST (e.g. deliberately not reporting sales by bypassing the system), heavy penalties apply under Singapore law – typically a penalty of 3 times the tax evaded, fines up to $10,000, and/or imprisonment up to 7 years for wilful tax evasion. These are existing GST penalties but would equally apply if e-invoicing data were intentionally manipulated or withheld to evade tax. [straitstimes.com] [straitstimes.com], [straitstimes.com]
• Penalties for Improper Record-Keeping: Even with e-invoicing, businesses must maintain and archive their invoices and related records (as discussed in section 9). Failure to retain proper records for the required 5-year period is an offence that can result in fines up to $5,000 and/or imprisonment (upon conviction) under the GST Act (this is also the general penalty for any GST offence without a specific penalty). For example, if a taxpayer were to delete or alter InvoiceNow records in an attempt to mislead IRAS, it could face charges under record-keeping violations or even more severe anti-fraud provisions.
• Enforcement Outlook: IRAS has communicated that it will exercise flexibility in the initial rollout: during the early phases, “genuine mistakes or errors” in e-invoicing will likely be met with advisory notices or guidance rather than immediate fines. However, as the system matures, enforcement will become stricter. By the final phases, non-compliance will be treated like any other GST violation. Businesses are therefore urged to treat the InvoiceNow mandate seriously and not view it as optional. IRAS has emphasized that the requirement is “not merely a technological initiative but a legal obligation” – once fully in force, failing to transmit required invoices is considered a failure to comply with GST regulations. Companies should also be aware that IRAS’s ability to compare transactional data with filed GST returns will be enhanced; significant discrepancies or missing invoices may trigger audits or queries. In short, the mandate will eventually be enforced with financial penalties and other sanctions, so it’s critical to achieve compliance by the applicable deadlines to avoid punitive actions. [vatupdate.com]

11. Pre-Filled VAT Returns
    Despite the comprehensive collection of invoice data, **Singapore’s e-invoicing initiative does not yet include pre-populated GST returns. Businesses are still responsible for preparing and filing their periodic GST returns (Forms F5/F7) as before, consolidating the figures for output tax, input tax, and other disclosures. The InvoiceNow transmissions serve to support tax administration and improve accuracy, but IRAS is not currently using the data to automatically populate taxpayers’ GST returns. In the official e-Tax Guide and public statements, IRAS has clarified that the e-invoicing requirement is “in addition to (not a replacement for) regular GST filings”. [vatupdate.com]

• No Immediate Plans for Pre-filling: IRAS has not announced any near-term implementation of pre-filled GST returns. The focus of InvoiceNow is on improving compliance (through better record integrity and easier audit verification) rather than shifting the filing responsibility. In the future, once the system is fully operational and all businesses are e-invoicing, IRAS will have a rich dataset of sales and purchase information. This could potentially enable new services – for example, providing transaction listings or data summaries to assist in return preparation or even cross-checking input tax claims automatically. However, as of 2026, taxpayers must continue to manually compile and submit their GST returns; IRAS does not issue pre-filled GST returns based on e-invoice data. [vatupdate.com]
• Taxpayer Review Still Required: Even if IRAS were to introduce pre-filled returns in the future, businesses would likely need to review and confirm the data (much as is seen in some other countries’ systems). For now, the e-invoicing data stream is mainly used by IRAS for behind-the-scenes risk analysis and possibly for offering services like faster GST refunds (since IRAS can verify claims more quickly). But the accuracy of the GST return remains the taxpayer’s responsibility, and the e-invoicing mandate does not change the filing process for GST returns in 2023–2026. Taxpayers should ensure that the totals on their GST F5 returns reconcile with the aggregate of e-invoices they’ve submitted for the period, making any needed adjustments or corrections before filing.

12. Impact on SMEs and Startups
    Singapore’s phased approach heavily considers the circumstances of SMEs (small and medium enterprises) and new startups, aiming to balance compliance goals with support measures. SMEs will face both new compliance obligations and opportunities for digital transformation under the e-invoicing mandate. Key points:

• Phased Onboarding and Thresholds: As detailed in section 3, smaller businesses (by annual turnover) are scheduled to join the mandate in the earlier phases (2028–2030). This somewhat counter-intuitive approach – onboarding the smallest companies before the largest – was chosen so that SMEs could receive focused government support and enjoy the benefits of e-invoicing sooner. It also reflects that many SMEs use off-the-shelf software (often cloud-based) that can be updated quickly via vendors, whereas large MNCs might need longer lead time for complex internal system upgrades. There are no permanent turnover-based exemptions: once fully phased in by 2031, even the smallest GST-registered micro-enterprise must use e-invoicing. However, unregistered micro businesses (below the S$1M threshold that remain unregistered for GST) are not directly affected, since the mandate ties to GST registration. [imda.gov.sg], [imda.gov.sg]
• Support Measures and Subsidies: The government has introduced numerous support initiatives to help SMEs and new businesses adopt InvoiceNow. At the 2026 Committee of Supply, it was announced that free InvoiceNow-ready solutions will be made available to all SMEs until March 2031, and cash grants will be provided to defray implementation costs. Specifically, small and mid-sized businesses can receive grants of up to S$1,000 each, while larger businesses can receive up to S$5,000 for early adoption of e-invoicing solutions. These grants (available likely as one-time support per entity) are meant to cover software subscription or integration costs. In addition, IMDA had earlier launched an “InvoiceNow Accelerate” program offering newly incorporated businesses one year of free access to an InvoiceNow solution in 2024–25. Furthermore, existing schemes like the Productivity Solutions Grant (PSG) can subsidize up to 50% of approved digital solution costs for SMEs adopting e-invoicing software. Training resources and webinars are being provided jointly by IRAS and IMDA to guide businesses, and a list of free or low-cost InvoiceNow service providers is published on the IMDA/IRAS websites. [imda.gov.sg], [imda.gov.sg] [fonoa.com], [fonoa.com] [dtl.sg], [dtl.sg]
• Compliance Costs and Operational Impact: For many SMEs and startups, complying with the mandate will require upgrading or replacing their billing systems, which introduces one-time and ongoing costs. These might include software subscription fees, IT consulting or setup charges, and staff training. The government support measures described above are aimed at minimizing these out-of-pocket costs. In fact, there are several free e-invoicing platforms and tools available, meaning a small business could potentially comply with InvoiceNow at little to no monetary cost. On the other hand, businesses that use more integrated ERP systems may incur some cost to ensure InvoiceNow compatibility (e.g. engaging their vendor or IT team to implement the required API connections), but the S$5k grant for larger firms is intended to offset this. [imda.gov.sg], [imda.gov.sg]

From an operations perspective, once set up, e-invoicing can actually streamline processes for SMEs. Automation of invoice delivery and reduced manual data entry can save significant time. A study by Deloitte found that small businesses could save up to ~S$20 per invoice by using digital e-invoices instead of manual processes. By eliminating the need to print, mail, or email PDFs – and by auto-populating accounting entries – companies can cut administrative overhead. Cash flow can also improve: E-invoicing ensures invoices reach customers faster and more reliably, potentially leading to quicker payments. In the public sector, the Singapore government has stated that once e-invoicing is widespread, it could enable faster GST refund processing and earlier detection of errors for businesses, which helps cash flow and compliance for SMEs. Early adopters have reported reduced payment times and fewer invoice disputes, since both buyer and seller have a synchronized view of the invoice data. [sg.news.yahoo.com] [imda.gov.sg], [imda.gov.sg]

• Administrative Burden vs. Simplification: There is an initial learning curve and administrative effort for SMEs to implement InvoiceNow – they must select a solution, register for a Peppol ID, possibly adapt their chart of accounts to map GST codes, and train staff. However, these are largely one-time setup tasks. The ongoing use of e-invoicing is expected to reduce administrative burdens. For instance, manual keying of supplier invoices can be eliminated when those suppliers send e-invoices that integrate with the SME’s accounting system, freeing staff from data-entry and minimizing human errors. The IMDA reports numerous positive feedback from SMEs using InvoiceNow, citing reduction in invoicing errors and time spent handling invoices. Over time, as paper-based invoicing is phased out, even processes like GST compliance checks and audits may become simpler (because businesses and IRAS will be looking at the same data). [sg.news.yahoo.com], [sg.news.yahoo.com]
• Market Impact and Digitalization: The e-invoicing mandate is part of Singapore’s Smart Nation push and is expected to accelerate digitalization among SMEs. Firms that embrace e-invoicing early could gain a competitive advantage – for example: better integration with large customers’ systems (some MNCs may prefer suppliers who can send Peppol invoices), improved financial management, and readiness for other digital economy initiatives. Conversely, SMEs that delay may face challenges if they are suddenly required to comply without preparation. This is why government agencies are proactively reaching out via trade associations (like SBF and chambers of commerce) to raise awareness. There is also the broader context of international alignment; Singapore’s use of Peppol means SMEs will be well-placed to handle cross-border e-invoicing in the future, as more countries (including those in the EU, Australia, New Zealand, and more) adopt similar standards. [Articles a…rs exter 1 | Word]
• SME Readiness: Government assessments indicate a growing uptake of the system. As of early 2026, about 63,000 businesses (many of them SMEs) have already joined InvoiceNow, and the government expects around 90,000 more businesses – largely SMEs – to come on board by the final phase in 2031. The staged rollout and support measures were designed to give smaller businesses adequate time and resources to adapt. Overall, SMEs are encouraged to view the mandate not merely as a compliance cost, but as an opportunity to modernize. The government has framed e-invoicing as a catalyst for efficiency: Senior Minister of State for Finance highlighted that SMEs can reduce compliance costs and errors through digital invoices, and cited examples of SMEs benefiting from moving away from paper processes. Early engagement with software providers or accounting firms is advised so that SMEs can smoothly transition and even use the mandate as a chance to upgrade their business processes. [sg.news.yahoo.com], [imda.gov.sg] [sg.news.yahoo.com], [sg.news.yahoo.com]

13. Official References (for further detail and verification):

• Inland Revenue Authority of Singapore (IRAS) – “GST InvoiceNow Requirement” (official guidance and FAQs on the e-invoicing mandate). [iras.gov.sg], [iras.gov.sg]
• IRAS e-Tax Guide (Mar 2025) – “Adopting GST InvoiceNow Requirement for GST-registered Businesses (First Edition)” – comprehensive official guide with technical details and examples. [iras.gov.sg], [iras.gov.sg]
• IMDA Factsheet (Feb 2026) – “Extension of GST InvoiceNow Requirement to All Businesses by 2031” – government announcement of the mandate’s full rollout timeline and support measures. [imda.gov.sg], [imda.gov.sg]
• IRAS & IMDA Webinar Materials and Technical References – InvoiceNow Technical Playbook (for IT integration) and lists of accredited Solution Providers and Access Point providers (available on IRAS/IMDA websites). [iras.gov.sg]
• News and Analysis by Tax Professionals: e.g. VATupdate briefing “Singapore’s E-Invoicing & E-Reporting Mandate (InvoiceNow)” (Apr 2025), EY Indirect Tax Alert (May 2025) summarizing the e-Tax Guide, PwC Tax Bulletin (Jun 2024) on key highlights, and Fonoa blog (Feb 2026) on the mandate’s expansion and grants for SMEs. [vatupdate.com], [vatupdate.com] [ey.com] [pwc.com] [fonoa.com]
• Legislative Text: Goods and Services Tax (Amendment) Act 2023/2024 – amended the GST Act to empower IRAS to mandate electronic invoicing (see Singapore Parliament MOF Committee of Supply 2024 announcements). Statutory penalties for non-compliance are in the GST Act (e.g. Section 46 on tax invoicing obligations; General Penalty under Section 58: fine up to $5,000 for offences with no specific penalty). [straitstimes.com]

(Additional useful resources: IMDA’s “InvoiceNow” portal for businesses, the Singapore Peppol Authority site for technical specifications, and various accounting software vendor guides on implementing InvoiceNow. Big 4 firms and local tax consultancies have published numerous guides on this topic (e.g. KPMG TaxNewsFlash, Deloitte Tax News, TJC Group whitepapers, etc.), which may provide further interpretation and practical tips.)

14. Summary
    Singapore’s InvoiceNow e-invoicing and e-reporting framework marks a major step in modernizing GST compliance. Below is a high-level overview of its key elements and implications:

• Scope: All GST-registered businesses in Singapore will be required to transmit their sales and purchase invoice data to IRAS using the InvoiceNow e-invoicing network. In-scope transactions include essentially all B2B, B2C, and B2G supplies that are reportable for GST (standard-rated and zero-rated supplies, as well as input-tax-bearing purchases). Only a few specific transactions (e.g. purely exempt supplies, reverse-charge transactions, and certain no-invoice scenarios) are excluded. Even special cases like self-billed invoices and domestic reverse-charge supplies are accommodated within the system (with appropriate annotations and codes). In short, if a GST-registered business issues a tax invoice or credit note, it will need to be sent to IRAS in digital form. [ey.com] [ey.com], [ey.com]
• Timeline: The mandate is being phased in from 2025 through 2031. It began with voluntary adoption (from mid-2025) and becomes mandatory in stages: new GST registrants (voluntary) must comply from Nov 2025/Apr 2026; then small and newly compulsory businesses by 2028; medium businesses by 2029–30; and all remaining (including large companies) by 1 April 2031. This phased approach gives businesses time to prepare and allows the government to provide support (particularly to SMEs) during the transition. By 2031, electronic invoicing and reporting will be the norm for every GST trader in Singapore. [iras.gov.sg]
• Key Obligations: Businesses must use an InvoiceNow-compliant solution (accounting software or service provider) to electronically transmit specified invoice data to IRAS. In practice, this means obtaining a Peppol ID and ensuring your finance system can generate and send invoices in the required XML format. For B2B transactions with partners also on InvoiceNow, the e-invoice will be delivered to your customer through the network and simultaneously reported to IRAS. For other transactions, the invoice data is sent to IRAS only. Data must be submitted by the due date of the GST return for the relevant period (no later). All required fields (business particulars, invoice details, line-item and tax information) must be included. If mistakes occur, businesses need to fix them via credit notes or adjustments and ensure the corrected data is transmitted (and reflect the correction in their GST return). [cleartax.com], [cleartax.com] [vatupdate.com]
• Enforcement & Risks: Initially, IRAS is focusing on educating taxpayers and refining the system. However, this is a legal mandate, not just a best practice. Non-compliance after your go-live date can result in penalties. In the short term, IRAS can refuse or cancel GST registrations for businesses that don’t comply. In the longer term, failing to issue/transmit e-invoices when required can lead to fines (up to $5,000 per offence) and other penalties under the GST Act. Intentional evasion (e.g. deliberate omission of invoice data to hide income) can trigger severe punishment – including tax penalties (up to 3x the underpaid GST) and even imprisonment under Singapore’s anti-fraud laws. Bottom line: Businesses should treat e-invoicing obligations with the same seriousness as filing GST returns or issuing proper tax invoices, since errors or lapses will be visible to the authorities and enforceable under law. [vatupdate.com] [straitstimes.com], [straitstimes.com]
• SME Considerations: Small businesses and startups, which form the majority of GST-registered companies, will need to adopt e-invoicing but stand to benefit in time. The government has provided grants (S$1k for SMEs) and free software solutions to reduce upfront costs. Many “light” cloud accounting systems popular with startups have already incorporated InvoiceNow features. While there is an adjustment period, digital invoicing can save SMEs time and money by reducing manual paperwork – studies indicate significant cost-per-invoice reductions for SMEs that automate invoicing. Over time, SMEs may see faster payments and fewer invoice disputes as more of their customers and suppliers use the same network. However, SMEs must invest the effort to learn and integrate the new process, and possibly to reorganize some internal workflows (or upgrade legacy systems) to comply. The government has emphasized that early adopters will have an easier transition and even potentially enjoy competitive advantages (e.g. priority processing of GST refunds, more efficient operations, integration with overseas partners). [imda.gov.sg], [imda.gov.sg] [sg.news.yahoo.com]
• Critical Dates & Next Steps: Businesses should identify which phase of the rollout applies to them (based on their GST registration status and 2025 sales volume) and mark the date when e-invoicing becomes compulsory. Well before that deadline, you should: select an InvoiceNow-ready software or provider; obtain a Peppol ID; configure and test your system; and train your staff. Key upcoming milestones include Apr 2026 (all new GST registrants must comply) and Apr 2028 (first wave of existing businesses mandated). Given the granular requirements and the potential need for IT changes, it’s advisable not to wait until the last minute. Leverage the available resources – IRAS’s e-Tax guide and webinars, technical playbooks, industry guides, and solution provider support – to get prepared. The move to e-invoicing is a significant change, but it aligns with global trends and promises long-term benefits in efficiency, accuracy, and integration. By acting early, businesses can turn compliance into an opportunity to modernize their invoicing and financial processes, while avoiding the pitfalls of non-compliance.