Skip to main content
A Singapore Government Agency Website How to identify
Official website links end with .gov.sg
Government agencies communicate via .gov.sg websites (e.g. go.gov.sg/open). Trusted websites
Secure websites use HTTPS
Look for a lock () or https:// as an added precaution. Share sensitive information only on official, secure websites.
WorkBuddy

DOs and DON'Ts of using Postman for SMS communications

Learn the dos and don'ts of using Postman for SMS communications, including allowed message types, link usage rules, and character limits.

Last updated 15 April 2026

Message Types and Requirements

Can I use my own SMS aggregators to send SMS messages to citizens and mixed groups?

All one-way SMS communications to citizens or mixed groups must be sent using Postman V2 by Open Government Products (OGP). Agencies are not allowed to engage external SMS aggregators.

What types of messages can I send?

You should only send essential/critical SMS messages to citizens or mixed groups. The sending of non-critical or generic messages3 to citizens or mixed groups using the "gov.sg" sender ID is not allowed. Refer to the table below for examples of non-critical and critical messages. More details can be found in SD Directive 03-2022 - Management of MINDEF/SAF’s Direct Channels of Communication.

Aside from the critical messages listed, you may also send SMS messages to citizens and mixed groups containing pre-event related details (e.g., RSVP confirmations, digital Admin Instructions).

Examples of non-critical and critical messages

Non-Critical

Critical

  • General feedback or post-event polls or surveys4

  • Holiday greetings

  • Promotions (e.g. promotions of courses, promotions of new app features)

  • Messages of appreciation

  • Requests for donation

  • One-Time Password (OTP)

  • Appointment bookings or reminders

  • Updates on transactions with MINDEF/SAF (e.g. applications on OneNS)

  • Follow-up on requests

3 “Generic messages” are messages with no call-to-action or are not related to the citizen’s transactions with MINDEF/SAF.

4 Polls or surveys commissioned at the national or organisation level in support of strategic defence objectives (e.g. defence opinion polls, policy research) may be assessed for deviation.

Does prior notification to the target recipient to expect an SMS message change the nature of the message from 'non-critical' to 'critical'?

No.

Can I send an SMS and get their response via SMS?

No.

Use of Links

Can I send links in the SMS?

By default, you should not send links in SMSes. However, there are exceptions where non-login links may be sent. Some scenarios include:

  1. The link was requested by the customer, who is expecting the link from MINDEF/SAF; OR

  2. The customer is less digitally-savvy and found it difficult to locate the webpage despite personalised instructions.

What are the requirements if a link is approved to be used in the SMS?

If approved, the link must meet these requirements:

  1. The link must use a GoGovSG URL shortener (https://go.gov.sg). This is because only public officers with a gov.sg email domain can generate GoGovSG links, ensuring that the public can trust that the links are official and not from scammers.

  2. Agencies must use a GoGovSG URL shortener to shorten links, subdomains and subdirectories where possible. This reduces the total character count of the message and the corresponding SMS cost.

Can I send non-login links in an SMS?

There are exceptions allowing non-login links to be sent in an SMS message. The SMS must be a solicited message and part of MINDEF/SAF’s day-to-day operations:

  1. Where there is an established relationship between MINDEF/SAF and Members of Public (MOP)

  2. Where the MOP is expecting to receive the link (e.g., links that are sent in response to a MOP’s action)

Length and Format

What is the maximum number of characters and segments permissible for each SMS?

Postman allows a maximum of 1000 characters for the message body, excluding the header (agency's name) and footer. However, users are strongly encouraged to limit their message body to 320 characters (excluding the header and footer) and keep messages under 7 segments to ensure reliable and timely message delivery.

What will happen if my SMS message contains unsupported characters?

On the Admin Portal: Campaign templates that contain unsupported characters cannot be created on the Postman admin portal. This blocking has been implemented since June 2024.

On the API layer: Message content containing unsupported characters will be blocked from sending. Postman Team has implemented the blocking on the Postman production environment from 5 May 2025.

How do I count total characters, number of segments and identify unsupported characters?

Visit https://message-segment-calculator.postman.gov.sg to use the Postman Message Segment Calculator tool to count your total characters, number of segments and identify any unsupported characters.

Can I paste message content into Postman from another editor/MS Word/Outlook etc?

It is recommended that you do not paste message content into Postman from another editor/MS Word/Outlook etc. as this may convert characters into unsupported (non-GSM-7) characters. Please type the message content directly into Postman.