Bulletin
4notify Singapore · Government Gazette
OFFICIAL · IMDA · Singtel · M1 · StarHub · SIMBA
Bulletin No
BUL-SG-002
Date
2026-05-27
Status
In force
Category
Telecommunications

IMDA numbering plan, SMS Sender ID Registry (SSIR) and A2P routing to Singapore

Whereas, in exercise of the powers conferred by the Telecommunications Act, the Infocomm Media Development Authority (IMDA) administers the national numbering plan for +65 and the SMS Sender ID Registry (SSIR). Four mobile operators serve the island: Singtel, M1, StarHub and SIMBA (formerly TPG). 4notify routes via direct tier-1 carrier interconnect with all four, registers Alphanumeric Sender IDs through SSIR, and applies the Likely-Scam label policy at the API edge.

SMSVoice
Preamble

Whereas, in exercise of the powers conferred by the Telecommunications Act and the National Numbering Plan administered by the Infocomm Media Development Authority, the present Bulletin is hereby published concerning A2P SMS routing into Singapore and the registration of Sender IDs through the SSIR.

Statutory basis
Telecommunications Act (Cap. 323)

IMDA's competence over the national numbering plan and Sender ID identification rules.

National Numbering Plan (IMDA)

Allocation of +65 ranges, mobile numbering and short codes.

IMDA SMS Sender ID Registry (SSIR)

Mandatory registration of Alphanumeric Sender IDs since the full SSIR mandate; non-registered IDs default to 'Likely-Scam'.

Implementation
01

IMDA SSIR registration plus operator contracts

4notify is registered through the SSIR as a participating aggregator and holds Sender ID agreements with Singtel, M1, StarHub and SIMBA.

02

Alphanumeric Sender ID enrolment

Brands register their Sender ID (e.g. 'DBS-Bank', 'SingPost') through the SSIR. Requirements: ACRA-registered entity or recognised trademark, sample message, declaration of use. Activation in 5-10 working days.

03

Likely-Scam policy enforcement

Any unregistered alphanumeric ID is rewritten as 'Likely-Scam' by all four operators. 4notify rejects unregistered Sender IDs at the API edge — no message ever leaves with the Likely-Scam label.

04

STOP keyword and PDPA opt-out processing

For every commercial message, STOP and UNSUBSCRIBE are processed within 3 days and propagated to the suppression list, in line with PDPA and DNC obligations.

Delivery envelope
json
{
  "event": "sms.delivery",
  "destination": "+6588881234",
  "sender_id": "SingPost",
  "ssir_token": "SG-SSIR-2026-SINGPOST-30A4F9",
  "text": "SingPost: Your parcel 481923 is out for delivery. Track: spost.sg/abc. Reply STOP to opt out.",
  "ssir_verified": true,
  "carrier_route": "singtel_direct"
}
Sample message
SMS

SingPost: Your parcel 481923 is out for delivery today between 2pm and 4pm. Track: spost.sg/abc. Reply STOP to opt out.

Compliance checklist
  • IMDA SSIR aggregator participation current
  • Alphanumeric Sender ID registered across Singtel, M1, StarHub and SIMBA
  • API edge enforces SSIR token check (cache no older than 5 minutes)
  • STOP processing within 3 days documented for PDPC
The 4notify difference

4notify is the only A2P provider with simultaneous SSIR-registered tier-1 Sender ID coverage across Singtel, M1, StarHub and SIMBA, with API-edge enforcement of the Likely-Scam policy in line with IMDA's full SSIR mandate.

Frequently asked questions
Do I need a Singapore-incorporated entity to send SMS into Singapore?

For SSIR Sender ID registration, IMDA expects either an ACRA-registered entity or a recognised trademark holder. 4notify routes traffic from European infrastructure but accompanies the SSIR application through the four operators.

What does the 'Likely-Scam' label mean for my customers?

Since the full SSIR mandate, all unregistered alphanumeric Sender IDs are rewritten as 'Likely-Scam' on the recipient's handset. Only IDs registered through the SSIR display the brand name. 4notify blocks unregistered IDs at the API edge so the label never appears against your brand.

Published
4notify Operations Office
2026-05-27 · BUL-SG-002

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