What is SMS notification?
SMS notification is the ability for your app to send text messages to users' mobile phones in response to events — a one-time passcode for login, an appointment reminder the day before, a delivery status update, or an urgent alert that can't wait for the user to check their inbox.
Unlike email, SMS is almost universally opened within minutes, making it the right channel for time-sensitive messages. The tradeoff is per-message cost (usually a few cents per SMS for Australian numbers) and stricter opt-in requirements under Australian law.
The integration itself is straightforward: your app calls an SMS provider's API with a phone number and message body, and the provider handles routing and delivery to the carrier network.
When does your app need it?
- You need to deliver one-time passwords (OTPs) for two-factor authentication or phone number verification
- Your app makes bookings or appointments and needs to remind users the day before or day of
- You have a delivery, dispatch, or logistics workflow where real-time status updates are expected
- Users have opted in to receive alerts and email is too slow or too easy to miss
- You need to confirm high-value actions (e.g. a large financial transaction) with an out-of-band SMS confirmation
- Your user base skews toward demographics or contexts where mobile notifications are more reliable than email
How much does it cost?
Adding SMS notifications typically adds 3–5 hours of development — roughly from $1,000 AUD.
This covers provider integration, one to three message types, opt-out handling, and basic error logging. Australian phone number formatting (stripping leading zeros, adding +61) is a small but important detail. International sending, two-way SMS, or high-volume queueing add scope.
How it's typically built
Popular providers for Australian apps include Twilio (global, widely used), ClickSend and Burst SMS (both Australian-owned, good for local compliance), and MessageBird. The app sends messages by calling the provider's REST API with the recipient's mobile number and the message text.
Phone numbers are stored in E.164 format (+61 prefix). Message templates are kept short — under 160 characters where possible — to stay within a single SMS segment and avoid higher per-message costs. Under the Australian SPAM Act 2003, SMS messages must include sender identification and a clear opt-out mechanism (typically "Reply STOP to unsubscribe"). Opt-out responses are handled via the provider's inbound webhook and stored against the user's record to suppress future messages. Note that ongoing per-message costs are a running operational expense separate from the build cost.
Questions to ask your developer
- Which provider will you use? Australian-owned providers like ClickSend and Burst SMS can simplify compliance and local support, while Twilio offers broader global coverage.
- Will you need two-way SMS (receiving replies)? Inbound SMS handling is a separate capability that adds to the build.
- Do users need to opt in explicitly? You'll need a UI flow to capture and record consent before sending marketing or reminder-style messages.
- Will you send to international numbers? Per-message rates vary significantly by country and some providers require different configuration per region.
- Is OTP delivery the primary use case? If so, consider whether an authenticator app or email-based OTP might reduce ongoing costs.
See also: Transactional email · Push notifications · App cost calculator