Singapore · IMDA · InvoiceNow · PINT SG · BIS 3.0

IMDA-Certified Peppol
Access Point for
Singapore InvoiceNow.

Full PINT SG document mapping, BIS 3.0 validation, C5 IRAS GST automation — and a forward-looking view on the transition to BIS 4.0. Built, tested, and live in Singapore's InvoiceNow environment.

Live
InvoiceNow — Nov 2025
PINT SG
Singapore Profile
BIS 3→4
Migration Ready
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PINT SG

Singapore's Peppol Invoice Profile

PINT SG (Peppol International Network of Trade — Singapore) is Singapore's national extension of the Peppol invoice standard. It defines precisely what a Singaporean Peppol invoice must contain, on top of the global BIS 3.0 baseline.

What PINT SG Adds Over Base PINT

The global PINT (Peppol International Network of Trade) specification is the shared baseline for cross-border Peppol invoices. Singapore's PINT SG profile extends it with fields specific to Singapore's tax and payment infrastructure.

The most significant addition is the GST treatment code — a mandatory field that tells IRAS exactly how each line item and the invoice total should be treated for GST purposes. Without correct GST treatment codes, the C5 IRAS data forwarding pipeline cannot function correctly.

The second major addition is the PayNow reference — enabling automated payment reconciliation for businesses using Singapore's real-time payment infrastructure.

I have implemented the full PINT SG document mapping — all mandatory fields, all optional extensions, and the Singapore-specific Schematron validation rules — and tested against the IMDA validator in both sandbox and production environments.

GST Treatment Codes in PINT SG
Code Description Applies To
SR Standard-rated supply Local taxable supplies at 9% GST
ZR Zero-rated supply Exported goods and international services
ES33 Exempt supply (Reg 33) Financial services, residential property
OS Out-of-scope supply Third-country sales, non-SG transactions
OP Out-of-scope (public) Government and statutory body transactions
Mandatory Extension
GST Treatment Code

Every PINT SG invoice must carry a GST treatment code at both the invoice header and line-item level. Required for C5 IRAS data forwarding. Missing or incorrect codes will cause IRAS submission failure.

Optional Extension
PayNow Reference

Enables the buyer to pay directly via PayNow by including the supplier's PayNow UEN, mobile number, or VPA in the invoice payload. Supported by most Singapore banks' e-invoice processing systems.

Validation
IMDA Schematron Rules

PINT SG invoices must pass IMDA's Schematron validation rules before transmission. I have implemented and tested all validation rules — including the SG-specific business rules beyond the base PINT Schematron.

Peppol BIS 3.0

The Document Format Standard

Peppol BIS Billing 3.0 is the document format layer of Peppol — it defines the structure, required fields, and validation rules for all Peppol invoices. PINT SG is built on top of BIS 3.0.

BIS 3.0 (Business Interoperability Specifications, version 3) aligns with the European standard EN 16931. It is based on UBL 2.1 XML and defines a common invoice structure that every Peppol Access Point and connected ERP must support.

BIS 3.0 covers the core invoice structure: header fields, supplier and buyer party information, delivery details, payment terms, line items, and tax totals. Country-specific extensions (like PINT SG) add fields on top of this base without breaking the global standard.

Validating a BIS 3.0 document requires passing both the UBL 2.1 XML schema validation and the Peppol Schematron business rules. PINT SG adds a third layer: the Singapore-specific Schematron for IRAS/IMDA compliance.

I have implemented BIS 3.0 document generation, mapping, and validation — including all mandatory field populations, the Singapore PINT SG Schematron, and testing against IMDA's official validation service.

BIS 3.0 Core Document Types
Invoice
BIS Billing 3.0

The primary Peppol document type. Covers B2B and B2G invoice scenarios. PINT SG adds GST treatment codes and PayNow reference.

Credit Note
BIS Billing 3.0

Issued to reduce the value of a previously sent Peppol invoice. Must reference the original document identifier.

Order
BIS Order 3.0

Purchase Order in the Pre Award → Post Award flow. Enables structured procurement from order through to invoice.

Order Response
BIS Order 3.0

Seller's confirmation or rejection of a received Purchase Order — with line-level acceptance, rejection, or substitution.

"Validated BIS 3.0 documents through IMDA's test environment" — including all document types, Singapore-specific extensions, and Schematron validation. The most common implementation failure I have seen is incorrect GST treatment code population at the line-item level. I have built the validation logic that catches these errors before transmission.
Looking Ahead

Planning for BIS 4.0

Peppol BIS 4.0 is the next major revision of the invoice standard. It is currently in draft and pilot stages. Here is what is changing, what it means for Singapore, and how to build BIS 3.0 today while remaining ready for the transition.

What BIS 4.0 Changes from 3.0
  • Revised XML namespace and schema version identifiers
  • Updated PEPPOL CIUS code lists aligned with EN 16931:2017+A1:2019
  • Stricter Schematron validation — some previously optional fields become mandatory
  • Improved alignment with international PINT profiles for cross-border consistency
  • Revised handling of allowances and charges at line-item level
  • Updated tax category code list (aligns VAT exemption codes with EU updates)
What Stays the Same
  • Still based on UBL 2.1 XML (no format change)
  • The 4-corner (and 5-corner) routing model is unchanged
  • AS4 messaging protocol is unchanged
  • SMP/SML participant discovery is unchanged
  • PINT SG GST treatment codes remain — IMDA will issue SG-specific BIS 4.0 guidance
  • Core field semantics (supplier, buyer, amounts, tax) are mostly preserved

Timeline & IMDA Guidance

As of 2025–2026, BIS 4.0 is in draft and pilot phase — OpenPeppol and national authorities are testing it in sandbox environments. IMDA has not yet mandated BIS 4.0 adoption for Singapore's InvoiceNow. The current mandate is BIS 3.0 / PINT SG.

Expect a phased adoption window of 2025–2027 in which both BIS 3.0 and BIS 4.0 documents will be accepted by compliant Access Points, before a final BIS 3.0 sunset date. IMDA will publish specific Singapore guidance on the PINT SG 4.0 profile when the standard is finalised by OpenPeppol.

If you are building a Peppol integration today: implement BIS 3.0 — it is the current mandate. But architect your document generation layer so that namespace identifiers, code lists, and Schematron validation are configuration-driven rather than hardcoded. This makes the BIS 4.0 migration a configuration update, not a code rewrite. I monitor OpenPeppol's BIS 4.0 drafts and will migrate client implementations when IMDA mandates adoption.
C5 — The 5th Corner

IRAS as the 5th Corner

Singapore's InvoiceNow goes beyond B2B document exchange. IRAS receives invoice data directly from Access Points — enabling automated GST return pre-population for connected businesses.

In the standard Peppol 4-corner model, documents flow from C1 (Sender) → C2 (Sender's AP) → C3 (Receiver's AP) → C4 (Receiver). Singapore added a 5th corner: IRAS.

When an invoice travels from C2 to C3, the sender's Access Point simultaneously forwards GST-relevant data to IRAS — including the GST treatment code, invoice total, GST amount, and both parties' GST registration numbers.

IRAS uses this data to pre-populate GST F5/F7 returns, cross-check filed returns against actual invoice data, and enable near-real-time audit trails. Businesses using C5-capable APs experience dramatically reduced manual GST reconciliation effort.

Not every IMDA-certified Access Point supports C5 — you must verify that your AP is on the IMDA C5-capable AP list. I have personally configured the C5 IRAS forwarding pipeline, including the IRAS endpoint handshake and GST code validation layer.

C5 Quick Reference
  • IRAS receives data parallel to C3→C4 delivery
  • GST treatment code must be correctly set for C5 to function
  • Pre-populates IRAS GST F5 and F7 returns
  • Not all IMDA APs are C5-capable — verify before selecting
  • Reduces GST audit risk and manual reconciliation overhead
Full C5 Deep Dive →
Implementation Experience

Implemented, Not Theorised

Every item below is production Singapore Peppol work — from AP onboarding through to IRAS C5 forwarding.

🔗
IMDA-Certified AP Integration

End-to-end Access Point onboarding — verified against the IMDA AP register, connected and tested in the Singapore InvoiceNow environment.

🇸🇬
PINT SG Document Mapping

Full PINT SG implementation including all mandatory fields, GST treatment codes (SR, ZR, ES33, OS, OP), PayNow reference, and Singapore-specific Schematron validation.

📄
Peppol BIS 3.0 Validation

Document generation validated against IMDA's test environment — UBL 2.1 schema, Peppol Schematron, and Singapore PINT SG Schematron rules.

📡
AS4 Messaging Protocol

Protocol-level AS4 implementation — signed and encrypted transport, acknowledgement handling, error reporting, and message retry configuration.

⚡
C5 IRAS Forwarding Pipeline

GST code extraction, IRAS endpoint handshake, data forwarding configuration, and reconciliation logic. Tested in IMDA's production environment.

🔍
SMP/SML Registration

Peppol ID provisioning, SMP capability publication, and SML registration — enabling other APs globally to discover and route documents to connected businesses.

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Singapore Access Point?

Singapore InvoiceNow is now live for all GST-registered businesses. Whether you need AP onboarding, PINT SG mapping, or C5 IRAS configuration — first consultation is complimentary.

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