3 min read

User authentication: Getting the most out of SMS OTP

Fraud and security
SMS Verification
Share to:

Establishing digital trust with customers is a strategic requirement for most businesses. Success relies on exceptional user experiences, determining acceptable risks, and defining an operating model to suit. This isn’t easy, especially at scale. If you want to reach millions of people, solutions need to be accessible, usable, and appropriate for the needs of the business and its users. 

From a digital security perspective, it’s widely understood that two-factor authentication (2FA) can offer the biggest uplift in end-user security. OTPs delivered over SMS have been the most popular method for many years thanks to a long list of well-known benefits: 

- Standard, built-in channel on all mobile devices 

- Familiar and comfortable way of communicating 

- Unmatched reach, ease of use, and affordability 

- Secure-enough for most use-cases 

Image showing a verification phone screen

Of course, there are many more reasons why the world relies on text messages for verification - check out our white paper on SMS-based 2FA and find out why it’s here to stay.

If you plan on building your own verification solution, the good news is that Sinch has the best SMS network and enterprise-grade platform around. Robust enough to access all mobile operators globally, in fact. But your verification application needs more than just great SMS delivery. You also need to think about how to: 

- Manage connectivity providers and operators 

- Monitor route latency to make sure the fastest routes are always available 

- Maintain high-security levels 

- Keep up to date with global compliance and regulation issues 

- Plan for engineering resources, development costs, and maintenance 

In addition, you really need to think through how to measure service quality and performance. Companies that self-build SMS OTP verification solutions rely on delivery receipts (DLRs)

DLRs are great if you want to know a message has been delivered. But delivery doesn’t mean conversion. It just means a message was received. Sometimes DLRs experience delays and don’t always indicate delivery to the handset. They might show that the recipient network has received the message and it's ready to send to the end-user, but that’s no guarantee it arrived with the end-user. 

You need more information than that, right? 

In short, the best way to manage service quality for one-time passwords is to report successful conversions. Optimizing for conversion requires real-time analytics and multiple independent SMS routes. Bases need to be covered if one route is underperforming. 

With Sinch Verification, we constantly monitor routes and select those with the highest conversion rate. That means you get the best conversion rates and the best information on those conversions. 

Verification API: Next level SMS verification 

Built on the sturdy foundations of Sinch’s tried and tested SMS API, trusted carrier integration, and telco experience, Verification API takes SMS OTP to the next level. Removing the complexity of building your own solution yet offering the ability to customize, Verification API comes with benefits that truly set it apart from SMS API: 

- SDKs and REST API to support quick and easy verification services and solutions set up 

- Conversion rates as a quality metric instead of DLRs 

- Up to 11% higher app conversion rates compared to traditional SMS API 

- Access to real-time analytics on conversion rates, fault detection, and prevention 

- Cost, security, and UX optimization through blending verification methods and fallback management 

- Secure-by-design and future proof solution for mobile and web applications 

- Built-in compliance with local and global regulations 

- Reduced costs due to fewer OTP SMS resend requests 

- No hidden costs: pay per transaction

Sounds good, right? But don’t just take our word for it. Check out what EasyPark Group had to say:  

“Since we launched Sinch Verification in our app, our conversion rate went up by about 7% compared to our previous supplier. This is a huge increase for us; the numbers are much more stable now than previously, and the errors and support cases have essentially stopped altogether.” - Robert Petersen, Business Developer at EasyPark Group. 

Learn more on how EasyPark Group benefits from Sinch Verification API.


A future proof verification solution at scale 

On top of all the above, Verification API opens the doors to a world of verification services all available through a single integration point: 

Diagram showing verification

- World-leading SMS Verification with unmatched direct connect coverage 

- Market-leading Flash Call Verification for attractive cost savings 

- Data Verification (open beta) with market-leading security and UX for better user engagement 

- Phone Call Verification (or Voice Verification) to verify users over mobile or landline numbers to support accessibility and digital inclusion 

Plus, with Verification API, when new verification services are released, you’ll be one of the first to know. 

Want to learn more about how Verification API helps make a secure and seamless UX? Take a look at our white paper: Building a smooth, secure experience with SMS-based 2FA for tips and best practices, or check out the product page. 


Ready to get started with Sinch Verification API?  

Our SMS authentication integrates seamlessly into sign-up or login flows via our REST API: 

Sign up for a free account  

- Send an SMS Verification request to a number of your choice  

- Send a report verification request with the code received 

- Done!

Want to try our Verification SDK for iOS, Android, or Java? See documentation for more details.