Ordinance
4notify Hong Kong · Government Gazette
OFFICIAL · OFCA · Mobile carriers
Ordinance No
ORD-HK-002
Date
2026-05-27
Status
In force
Category
Telecommunications

OFCA numbering plan, Sender ID registration and A2P routing into Hong Kong

The Office of the Communications Authority (OFCA) administers the Hong Kong numbering plan and the rules for alphanumeric Sender ID under the Telecommunications Ordinance (Cap. 106). Five mobile networks cover the territory: CSL (HKT), 3HK (Hutchison), SmarTone, China Mobile Hong Kong and China Unicom Hong Kong. 4notify routes through tier-1 direct interconnections with all five, registers the alphanumeric Sender ID with each carrier and enforces the Do-Not-Originate list at the API edge.

SMSVoice
Preamble

Whereas, by virtue of section 8 of the Telecommunications Ordinance (Cap. 106) and the numbering-plan instruments issued by the Office of the Communications Authority, it is hereby ordained that A2P-SMS traffic terminating on Hong Kong mobile networks shall be routed with verified caller identification and a recognised alphanumeric Sender ID.

Statutory basis
Telecommunications Ordinance (Cap. 106)

Jurisdiction of the Communications Authority over the numbering plan and Sender ID arrangements; licensing of carriers.

OFCA Numbering Plan

Allocation of +852 ranges; mobile numbering, short codes and Sender ID conventions.

Unsolicited Electronic Messages Ordinance (Cap. 593)

Restrictions on commercial electronic messages, the unsubscribe facility and the Do-Not-Call registers operated by OFCA.

Implementation
01

OFCA filing + carrier contracts

4notify is filed with OFCA as a messaging provider and holds Sender ID agreements with all five Hong Kong mobile carriers.

02

Alphanumeric Sender ID registration

Brands register their Sender ID (for example "HSBC", "HKPost") with each carrier. Requirements: registered trade mark, sample message and use declaration. Activation: 5-10 business days.

03

Do-Not-Originate (DNO) list enforcement

Banks, government bureaux and emergency services may never be impersonated as Sender IDs. 4notify mirrors the DNO list at the API edge every five minutes.

04

Unsubscribe keyword handling

On every commercial message the keywords STOP and UNSUBSCRIBE are processed within three days under Cap. 593 and reflected in the suppression list.

Delivery envelope
json
{
  "event": "sms.delivery",
  "destination": "+85291234567",
  "sender_id": "HKPOST",
  "sender_token": "HK-MARK-2026-HKPOST-3001234",
  "text": "HKPost: parcel RR481923HK is out for delivery. Track: hkp.hk/abc. Reply STOP to opt out.",
  "dno_verified": true,
  "carrier_route": "csl_direct"
}
Sample message
SMS

HKPost: parcel RR481923HK is out for delivery and will arrive today between 14:00 and 16:00. Track at hkp.hk/abc. Reply STOP to opt out.

Compliance checklist
  • OFCA messaging-provider filing on record
  • Alphanumeric Sender ID registered with all five mobile carriers
  • DNO list verification at the API edge (cache ≤ 5 min)
  • STOP / UNSUBSCRIBE handling within three days documented
The 4notify difference

4notify is the only A2P provider with simultaneous Sender ID coverage across CSL, 3HK, SmarTone, China Mobile HK and China Unicom HK plus API-edge DNO list verification aligned with the OFCA numbering plan.

Frequently asked questions
Do I need a Hong Kong company to send SMS into Hong Kong?

No. 4notify operates tier-1 interconnections from European infrastructure. For Sender ID registration you need a trade mark with demonstrable ownership; we handle the filings with CSL, 3HK, SmarTone, China Mobile HK and China Unicom HK.

What is the DNO list and why does it matter?

It is the list of Sender IDs reserved for banks, government bureaux and emergency services that may never be impersonated. 4notify verifies it before every send to block sender-ID spoofing.

Published
4notify Department of Operations
2026-05-27 · ORD-HK-002

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