Australia One-time Password (OTP) SMS Provider Comparison Report

How to choose SMS & Voice OTP Providers in Australia

Australia SMS Verification Providers Report

Australia SMS/Voice OTP Providers and Mobile Phone Carriers

In each country there are multiple phone carriers. Australia has 3 major ones:

  • Optus
  • Telstra
  • Vodafone

To send SMS and voice OTP (also known as one-time PIN), a web service needs to communicate with a SMS/voice gateway, which sits astride the Internet and phone infrastructure. There are many SMS/voice gateway providers. The major global ones are Twilio, Infobip, Nexmo, MessageBird, etc., and there are regional ones like Cequens, Plivo, Tropo, etc.

Goal of Australia SMS/Voice OTP Provider Comparison Report

Our previous research shows that using a single provider never gives you the optimum SMS/voice OTP deliverability globally since each provider, depending on their complex partnerships with phone carriers in each region, etc., will excel in in some regions/carriers, while falling short in others.

In this study, we:

  • Use more providers
  • Focus on reliability measurements at country-level

This enables us to offer more insights about OTP delivery:

  • How important is choosing a single OTP provider?
    • You send an OTP re-request or auto-send an unconverted OTP through the 2nd provider to improve delivery
  • Does using 2 or more providers improve OTP reliability?
    • Section2 3 Point2 Pointa

We use Conversion Rate (number of requested OTP used/total number of requested OTP) as a yardstick to measure the reliability of SMS/voice OTP deliverability of each provider for each carrier.

Caveat Emptor: Conversion Rate is a good indicator of reliable OTP deliverability, but it is not a definitive one. Conversion Rate is skewed negatively by users who wrongly request for OTP when they do not need it, or users who change their mind about proceeding with the service/transaction after requesting for OTP.

Conversion Rate Data Measurements for Providers/Carriers in Australia

The table below shows how each provider (anonymized as P1 - P5) fare in terms of conversion rate for each Australian carrier. This data is used to answer the questions asked.

Australia SMS Verification Providers Data
Table 1: Provider-Carrier Conversion Rate Measurements

How important is choosing a single OTP provider in Australia?

Australia 1-SMS Verification Provider Data
Table 2: Reliability and Sensitivity of Each Provider in Australia


From Table 1, we can look at the data for each provider to derive Table 2:

  • Min: The worst conversion rate of the provider across all carriers
  • Max: The best conversion rate of the provider across all carriers
  • Ave: The average of conversion rate across all carriers for the provider
  • Sensitivity: The difference between Min and Max
  • Reliability: Average conversion rate but color-coded to help readability


We look at Reliability and Sensitivity.

From Table 2:
  • The best provider is P1, which gives you Reliability > 90% and Sensitivity of around 4%
    • The low sensitivity means P1 can deliver reliability across all carriers
  • The worst provider is P3, which gives you Reliability < 70% and Sensitivity of around 2%
    • The low sensitivity means P3 is has consistently poor reliability across all carriers

Thus in Australia, if you do not have provider reliability data, you can pick an outright poor provider, which results in bad user experience, and major loss of potential & existing users; there is a 20% difference in OTP reliability (between the worst and best OTP provider)

Does using multiple providers improve reliability of OTP deliverability in Australia?

Theoretically, we can combine 2 providers to improve the conversion rate. We can do this heuristically by we choosing 2 providers that is best for 2 of the 3 carriers. This is a combinatorial problem, which there are 3 possible combinations:

  • Best provider for Optus and Telstra
  • Best provider for Telstra and Vodafone
  • Best provider for Vodafone and Optus

Australia 2-SMS Verification Provider Data
Table 3: Reliability and Sensitivity of Each 2-Provider Combination in Australia


From Table 1, we can combine the conversion rate for each 2-provider combination to derive Table 3:
  • Min: The worst conversion rate of the 2 providers across all carriers
  • Max: The best conversion rate of the 2 providers across all carriers
  • Ave: The average of conversion rate across all carriers for the 2 providers
  • Sensitivity: The difference between Min and Max
  • Reliability: Average conversion rate but color-coded to help readability


In our 2-provider combinations, P3, P4 & P5 were never used because they were not the best providers for any of the 3 carriers.

P1 & P2 is the best combination for all cases.

By selecting the best provider (Table 2), the best 2-provider combination (Table 3), and deriving the measurements for 3-provider combination from Table 1, we create a Strategy table (Table 4) as shown:

Australia SMS Verification Providers Strategy
Table 4: Comparing Strategy of Using 1, 2, and 3 Providers To Improve OTP Deliverability In Australia

The best one-provider, two-provider and three-provider combination have high Reliability (> 90%).

Two-provider and three-provider combination is superior to one-provider only in Ave, but only by 0.09%.

Comparison Summary For OTP Provider Reliability in Australia

Let us answer the questions posed about OTP provider in Australia:

  • How important is my choice when choosing to use a single OTP provider?
    • Extremely important because the OTP reliability varies drastically across OTP providers
  • What is the drop in OTP reliability if we choose a poor OTP provider?
    • The poorest provider has reliability < 70% compared to the best provider, which has reliability > 90%
  • Does using 2 or more providers help improve OTP reliability?
    • Yes but not much. Using 2 providers improves average reliability by 0.09%. Using 3 providers does not offer additional reliability gains

In Australia, even a single OTP provider can offer great reliability across carriers because the phone infrastructure is mature, and total number of carriers is low. However choosing this right OTP provider is really crucial. In other words, don’t risk choosing a wrong OTP provider, use RingCaptcha because we know the best providers/carrier combination for Australia.

Best Practices of Using Multiple OTP Providers

For best practice, always use at least 2 providers so that you can send a re-request for OTP, or auto-send an unconverted OTP through a fallback provider. This is seldom done in practice because:

  • You have to maintain relationship with at least 2 different providers
  • You have to write & maintain code for 2 different set of APIs
  • You have to continually test to ensure that fallback works

With RingCaptcha, you only maintain a single relationship with our SMS/voice OTP provider marketplace, develop for a single API, and you are never locked-in to any provider. What is more we build in all these OTP fallback features plus fraud mitigation features to you don’t have to - you just make a single API call to send OTP, and everything else magically happens in RingCaptcha.

Interested to boost your business with better transactional and notification SMS deliverability, we can make it happen. Talk to an expert now.