What is an alphanumeric sender ID?

An alphanumeric sender ID is a short piece of text, 2 to 11 characters, that appears as the sender of your SMS instead of a phone number. Your shoppers see NAKIE at the top of the message rather than +61 4XX XXX XXX.

Why brands ask for one

  • A phone number gives your shopper nothing to recognise before they open the message.
  • If you sent branded SMS on your previous platform, moving to a number is a visible change your shoppers will notice.
  • Your business name has to appear in every commercial SMS. On a sender ID it sits in the sender line rather than taking up characters in your message.

The standard setup in Australia

Every Australian brand on Instant sends from a numeric Australian number with a brand prefix at the start of the message. That is the standard path, it is included, and it needs nothing beyond your SMS verification.

A branded sender ID is an optional addition you can ask for. Your numeric number stays on your account either way. It is what you send from while a sender ID is being registered, and what you fall back to if a registration is ever rejected or revoked.

To start, tell your Customer Success Manager that you want to send under your brand name. They will confirm what applies to your business and open the request.

Before you start

Registration is mandatory in Australia

Since 1 July 2026, every alphanumeric sender ID used in Australia has to be registered on the ACMA SMS Sender ID Register. This is a regulator requirement, not an Instant one.

  • A sender ID that is not registered is stamped Unverified on delivery, and traffic from a provider that is not registered against it can be blocked.
  • The registration belongs to your business, not to Instant and not to your previous platform.
  • Each provider has to be authorised separately against your registration. There is no porting. If Klaviyo was authorised on your sender ID, Instant still has to be authorised on it before we can send.

Your starting point

Which path you are on depends on whether your business already holds a registration.

You already send branded SMS on another platform. Your entity and your sender ID are already on the register and you already have an ACMA Assist account. The remaining work is authorising Instant against the registration you hold. This is the shorter path and you have done the steps before.

You have never sent branded SMS. Your business needs to register with ACMA first, then the sender ID is registered against it. This takes longer and includes identity verification through ACMA Assist.

Shoppers cannot reply to a branded sender ID

An alphanumeric sender ID is one way. A shopper cannot text back, so Reply STOP to unsubscribe does not work and cannot be used as your unsubscribe instruction. Every SMS you send from a sender ID carries an unsubscribe link instead, which Instant adds for you.

What to prepare

Have these ready before you start. Anything that does not match your Australian Business Register record is the most common reason a registration is held up.

Your business details

  • Your legal entity name exactly as it is registered on the ABR, not your trading name. For example JDT GOODS PTY LTD, not Nakie.
  • Your ABN.
  • The name and email address of your authorised representative, matching the contact on your ABR record.

Your documents

  • Proof of business registration, such as your ABN extract or business summary from the ABR.
  • Proof of business address, issued in the last 6 months, showing your business name and full address.
  • Photo identification for your authorised representative.
  • If you already send branded SMS elsewhere, the ACMA approval email for your registration. This is the email from [email protected] that names your entity. There is a second email that says “submitted by” and names a provider, which is that provider’s authorisation rather than your registration, so send the one that names only your entity.

Your decisions

  • The sender ID you want, 2 to 11 characters. It has to match your registered business name, a registered business name you hold, a trademark you own, or your domain, and it has to pass ACMA’s restricted terms rules.
  • Who your authorised representative is. This person has to be reachable and able to sign in to ACMA Assist.
  • Whether you are keeping your previous platform sending SMS. Running two platforms on the same audience means duplicate texts, and shoppers are far less forgiving of duplicate texts than duplicate emails.

How it works

  1. You give your CSM the details and documents above.
  2. Instant sets up your business profile with our messaging provider and submits your sender ID registration under your entity.
  3. ACMA emails your authorised representative. That person signs in to ACMA Assist and confirms Instant’s authorisation. Nothing sends from your brand name until they do, so this is the step worth watching.
  4. Once the registration is approved, Instant attaches the sender ID to your account and your Australian SMS starts sending from your brand name.
  5. Your numeric number stays on your account as a fallback.

While all of this is in progress your SMS keeps sending from your numeric number. You do not lose SMS at any point in the process.

Your CSM will tell you when the registration is submitted, when ACMA needs your representative, and when your sender ID is live. If a registration is rejected, they will tell you the reason and what to change before resubmitting.

FAQ

Can my shoppers reply to a branded SMS? No. An alphanumeric sender ID is one way, so replies do not reach you and STOP replies do not work. Your unsubscribe link handles opt outs instead.

Can I move the sender ID approval I have with Klaviyo across to Instant? Not directly. Your registration stays with your business, but provider authorisations are separate and cannot be transferred, so Instant has to be authorised against it. That is a short step because your registration already exists.

Can I pick any brand name I want? No. The sender ID has to match your registered business name, a business name you hold, a trademark you own, or your domain, and it has to pass ACMA’s restricted terms rules. Your CSM will check your preferred sender ID before it is submitted.

Do I have to give up my Australian number? No. The number stays on your account, sends while your registration is pending, and is the fallback if a registration is rejected or revoked.

Does this apply to flows and campaigns? Yes. Once your sender ID is live it is used for every SMS Instant sends to Australian numbers, in both flows and campaigns.

What happens if my registration is rejected? Your SMS keeps sending from your numeric number. Your CSM will pass on the reason and what needs to change, then resubmit.

Is a sender ID available for SMS to other countries? No. This is an Australian sender option. United States numbers do not support alphanumeric sender IDs at all, so SMS to United States shoppers always sends from a number.

For the documents and steps to enable SMS in the first place, see Enabling Instant AI SMS in Australia.