Singapore — InvoiceNow · Peppol 5-corner with IRAS
Peppol InvoiceNow + GST 5-corner reporting · phased through 2031 — regulator: Inland Revenue Authority of Singapore (IRAS). Facts last refreshed: 2026-05-05.
POST /v1/documents/send.
TL;DR
- InvoiceNow is Singapore's nationwide Peppol network, run by IMDA since 2019; GST InvoiceNow adds IRAS as the 5th corner for tax reporting.
- Newly incorporated companies registering for GST voluntarily had to comply from 1 Nov 2025; all new voluntary registrants from 1 Apr 2026.
- All existing GST-registered businesses are absorbed in waves: 2028 (≤ S$200k), 2029 (≤ S$1m), 2030 (≤ S$4m), 2031 (> S$4m).
- Format: PINT-SG (Peppol International Invoice — Singapore CIUS) on UBL 2.1.
- IMDA = Peppol Authority; IRAS = tax authority receiving the 5-corner copy. Flowie is registered with IMDA.
Deadlines
| Date | Who | What |
|---|---|---|
| 2019-01-09 | All businesses (voluntary) | InvoiceNow Peppol network launched by IMDA. |
| 2025-05-01 | GST-registered (voluntary) | Soft launch of GST InvoiceNow. |
| 2025-11-01 | Newly incorporated companies registering for GST voluntarily | GST InvoiceNow mandatory. |
| 2026-04-01 | All new voluntary GST registrants | GST InvoiceNow mandatory. |
| 2028-04-01 | Existing GST-registered, supplies ≤ S$200k | Mandatory. |
| 2029-04-01 | Existing GST-registered, supplies ≤ S$1m | Mandatory. |
| 2030-04-01 | Existing GST-registered, supplies ≤ S$4m | Mandatory. |
| 2031-04-01 | All remaining GST-registered (> S$4m) | Universal scope reached. |
Background
Singapore was the first country outside Europe to join OpenPeppol as a Peppol Authority (IMDA, 2018) and built InvoiceNow as the national e-invoicing network on top. For the first six years it was purely voluntary — well-adopted in B2G via Vendors@Gov but light in B2B.
The 2024 IRAS announcement of GST InvoiceNow changes that. From 2025–2031, all GST-registered businesses must transmit invoice data via the InvoiceNow network so IRAS receives a real-time copy as the fifth corner of a Peppol 5-corner model. The phased rollout starts with new GST registrants and ends with all GST-registered businesses by April 2031.
Format is PINT-SG, a Singapore CIUS on Peppol International. Flowie's Singapore AP — registered with IMDA — handles routing to the buyer plus the IRAS reporting copy. Both are emitted from the same /v1/documents/send call.
Format profile
- PINT-SG (Peppol International Invoice — Singapore CIUS) on UBL 2.1.
- Seller and buyer UEN (Unique Entity Number) used as Peppol participant ID under scheme
0195:SG-UEN-.... - GST breakdown lines required even for zero-rated supplies.
- B2C invoices are out of scope of GST InvoiceNow but may still flow over InvoiceNow voluntarily.
Required fields
-
seller.uenstringrequired
Singapore Unique Entity Number; used as the Peppol participant ID.
-
seller.gstNumberstringrequired for GST-registered
Singapore GST registration number — required to claim GST on the invoice.
-
lines[].gstCategorystringrequired
Standard, Zero-rated, Exempt, or Out-of-scope per IRAS GST category codes.
Public sector (B2G)
| Hub | Peppol identifier scheme | Lookup |
|---|---|---|
| Vendors@Gov / InvoiceNow | 0195:SG-UEN- | https://www.vendors.gov.sg |
Government recipients are reachable on InvoiceNow via their UEN. Vendors@Gov is the legacy submission portal but Peppol delivery is now the recommended path.
B2B reporting / clearance
IRAS · GST InvoiceNow — 5-corner reporting copy of every GST-relevant invoice; auto-populates GST F5 returns.
| Lifecycle status | Reported as |
|---|---|
submitted | InvoiceNow message accepted; IRAS will receive a copy. |
rejected | Schema or business-rule violation; corrected document required. |
Error codes
Generic Peppol BIS schematron error codes apply (BR-*, EN16931-*); no country-specific overlays.
Testing in sandbox
| What you want to test | How |
|---|---|
| Singapore happy path | Sender UEN 200012345A, recipient any UEN in Flowie sandbox. |
FAQ
Is InvoiceNow mandatory for non-GST businesses?
No. Only GST-registered businesses are within scope of the GST InvoiceNow rollout. Non-GST businesses can use InvoiceNow voluntarily, which is increasingly common since government suppliers must.
References
Primary sources (government / regulator / standards body):
- IRAS · GST InvoiceNow Requirement — Authoritative GST InvoiceNow rules.
- IMDA · Peppol Service Provider Accreditation — Singapore Peppol Authority.
- OpenPeppol · Singapore profile — PINT-SG Peppol profile.
Industry analyses (vendor trackers — useful for cross-referencing):
- Avalara · Singapore InvoiceNow 2026-2031 — Industry analysis — phased timeline.