Australian SMS API providers compared Pricing Compared

The headline per-message rate is the smallest of the three costs in an Australian SMS budget. The first hidden cost is segmentation: as covered in the methodology, a single non-GSM character more than doubles the effective rate on anything longer than a tweet. The second is the dedicated virtual number. If two-way messaging is required, an alphanumeric sender will not do it, and that means a monthly number rental — typically five to fifteen dollars per number per month, sometimes with a setup fee, and almost never included in the per-message quote.

The third is the shape of the commitment. Prepaid credit models — ClickSend, SMS Broadcast, SMSGlobal, Cellcast, Kudosity — are pleasant right up until the expiry terms on unused credit surface, or until the good rate turns out to require buying a hundred thousand messages upfront. Postpaid and contract models push the other way: better unit economics, but a minimum spend committed before real send volume is known. For a product that has not launched, prepay at a worse rate and eat the difference; the option value of walking away is worth more than two cents a message.

One trap is specific to this market. Several providers quote "from" pricing achievable only on domestic traffic, sent from a domestic account, with a registered sender. Test with the actual message content, the actual sender ID and the actual recipient mix before committing, because international and roaming numbers sitting in a contact list bill at a completely different rate and nothing in the dashboard warns about it in advance.

SMS is the least locked-in category in this comparison set, and that should be exploited. The core operation is a POST with a destination, a body and a sender, plus a webhook that receives a status callback. Wrap that in a two-method interface on day one and switching providers becomes a config change rather than a project.

The genuine switching costs are elsewhere. A dedicated virtual number is portable in principle and painful in practice — porting between aggregators takes weeks and both parties have to cooperate. The opt-out list lives in the provider's suppression store unless it has been mirrored locally, and re-messaging someone who opted out at the previous provider is a compliance incident, not an inconvenience. Export it on a schedule. Delivery-receipt history is almost never exportable in bulk, so anyone reporting on deliverability should land those events in their own store as they arrive.

The one thing that cannot easily be replicated is reputation on a sender ID. A brand's alphanumeric sender that has been pushing clean traffic for two years is treated accordingly by carrier-side filtering, and a new provider starts that clock again. Plan an overlap period with both providers live and traffic shifted gradually, rather than a single cutover release that discovers the problem in production.

Prices are per outbound SMS segment to an Australian mobile number, in AUD, at three monthly volumes: 1,000, 10,000 and 100,000 messages. Where a provider publishes a public tier table, the figure is the list rate from that table. Where a provider quotes per account — MessageMedia, Telstra, Sinch and Esendex all do — the cell is null rather than a guess, because a made-up mid-market rate is worse than an honest gap. Twilio and AWS publish a flat per-destination rate with no public volume tiering, so their three tiers are near-identical; discounts exist but require sales. A segment is 160 GSM-7 characters or 70 UCS-2 characters. If your copy contains a curly apostrophe, an em dash or an emoji, you are paying UCS-2 rates for the whole message, which roughly doubles your bill on anything over 70 characters. Very few vendors say this on the pricing page.

The killer field, "self-serve API key", answers one question: from a cold start with a credit card and no prior relationship, can you obtain working credentials and deliver a message to a real Australian handset without speaking to a human? "Yes" means signup to sent message with no manual approval step. "Partial" means credentials are self-serve but something between you and production is not — a sender ID registration ticket, a manual account activation, a trial that cannot send to arbitrary numbers. "No" means a salesperson is in the critical path. A serious caveat on ACMA: Australia's SMS Sender ID Register regime has changed recently and the obligations on senders and on carriage service providers are in flux. Every cell in the ACMA Sender ID field is therefore deliberately left unknown rather than guessed. Vendor pages on this topic lag the regulator by months and several are simply out of date. This field is pending verification against ACMA directly and must not be relied on for any compliance decision — treat it as a prompt to go and check, not as an answer.