Setting the Sender ID on SMS Messages

New Zealand Sender ID Rules

In New Zealand, all A2P (Application-to-Person) messaging—which includes any SMS sent from a computer or application to a mobile phone must use a Short Code. This is a 3-digit to 6-digit number authorized by New Zealand mobile network operators.

• The Rule: You cannot send computer-based business SMS from a standard 021/022/027 mobile number. The Mobile Networks work with New Zealand's Department of Internal Affairs will block these messages to prevent spam.
• The Solution: TNZ assigns a Short Code to your account based on your message type (e.g. alerts, reminders, or marketing).

Shared vs. Dedicated Short Codes

New Zealand businesses have two primary options for their Sender ID. Most TNZ customers use a built-in Short Code due to its cost-effectiveness and ease of use.

→ See our Short Code guide.

When should you consider a Dedicated Short Code?

A dedicated number is recommended if you are:

• Running SMS Marketing campaigns where strict Spam Act compliance is vital.
• Sending sensitive links that require network-level whitelisting.
• Building long-term brand recognition around a specific number.
• Allowing mobiles to initiate the conversation (the mobile sends the first message).

Australia Sender ID Rules

The Australian market operates under ACMA (Australian Communications and Media Authority) regulations, allowing for more flexibility in the "From" field:

• Virtual Mobile Number (Long Code): A full-length mobile number. This is the default for TNZ customers in Australia as it allows for two-way communication (capturing replies).
• Alpha Sender ID: A brand name (up to 11 characters), such as "TNZ" or "YourBrand".

  Note: Alpha tags must be pre-registered and approved by the Australian networks to comply with anti-scam legislation.

→ See our Virtual Mobile Number and Alpha Sender ID guides.

Global Sender ID Rules

Each country sets its own rules for SMS Sender IDs.

TNZ will automatically handle setting the correct sender for you if the country's network operates allow it. If you message a specific country frequently, we can often provision a local number or register a localised Alpha tag to improve engagement and trust.

Some countries require additional compliance before you're allowed to send messages there. The SMS Geographies guide provides further detail.

How to Configure Your Sender ID

Your Sender ID is typically configured during account onboarding by your TNZ representative. Settings can be applied at two levels:

1. Per Account: One Sender ID applies to all users (e.g. all company messages come from the same code).
2. Per User/Group: Unique IDs for different departments (e.g. Support uses one code, while Sales uses another).

If you need to check your current Sender configuration or "Copy" settings from an existing user to a new one, please contact our support team.