Sept. 5, 2024
How can you verify that your users are really who they claim to be? In a world where user account security is of the utmost importance, verifying their phone number can help keep your users safe. Many organizations struggle with fraudulent behavior that can lead to accounts being hacked, and trust being lost between you and your users. That's where the Twilio Verify Phone Number API comes in. This amazing API not only streamlines and strengthens phone verification, but adds a layer of security to help protect your business and your users. In this post, I'll discuss how using Twilio for phone verification, and how easy it is to implement, you can strengthen your user verification strategy to onboard users quickly, more securely, in a way that's more compliant, and a better user experience.
Twilio Verify Phone Number is a great API for implementing phone verification in your user authentication process, a process that confirms phone numbers associated with your user accounts are real and belong to the user. Businesses like you are able to add an extra layer of security, making it more difficult for bad actors to pull off their scams. Instead of just securing your user accounts, you're also improving the registration and account management experience for your users.
Twilio Verify, among other things, lets you generate a one-time passcode (OTP) for phone verification. By sending a unique code via SMS or voice call (or even email), Twilio makes it easy for users to prove that yes, they do indeed own a particular phone number. With multi-channel, you can meet users where they are most comfortable, and you can make the process pretty smooth.
Twilio's Verify isn't a niche product: they support 4.8 billion per year, which demonstrates that Twilio API is effective for user verification in any industry, that it's dependable for user verification, and that it's secure for user verification. If Twilio didn't do it at that volume, we wouldn't trust that they were doing it right.
Companies use Twilio Verify to help secure user accounts and protect themselves from bad actors. By verifying phone ownership, they can reduce the risk of identity theft and account takeover. The OTP check not only checks that the person has the phone number you've registered—it's an additional wall to climb for anyone attempting to gain access. As user onboarding becomes more automated, having a reliable phone verification solution is key to gaining your users' confidence—and keeping them safe.
There's another really big reason to use Twilio Verify and it's compliance and regulations around user authentication and data protection. Privacy is a hot topic these days, and being compliant isn't just a box to check off, it's a powerful trust signal for your customers. With Twilio API you'll be in a good position to verify users safely and securely (without getting hacked!) and you'll be able to handle user data correctly, and follow best practices.
Twilio Verify Phone Number is also amazing for accelerating the rate at which you onboard users by validating their phone numbers quickly and accurately. The faster you onboard, the more users you'll onboard—nobody wants to fill out a long sign-up form.
Which means you can give your users a frictionless onboarding experience that gets them signing up quickly without unnecessary roadblocks. And, using Twilio's dashboard, you can monitor how well your verifications are working, and A/B test your signup flow to make sure no users fall through the cracks.
At the end of the day, Twilio Verify Phone Number is an incredibly easy way to increase user security, reduce fraud, and stay compliant while offering a better user experience, which is all anyone wants, right?
Twilio Verify is just one of the many ways you can add an extra layer of security and trust to end user verification when verifying end users. With this solution, businesses can enable 2-factor authentication in minutes and help make the web a safer place.
With Twilio's phone verification service, you can really bolster your user authentication by adding an extra layer of security with two-factor authentication (2FA). That's when users need to provide something they know (like a password) and something they have, like a one-time passcode (OTP) sent to their phone. Because of this extra layer of verification, it's nearly impossible for someone to steal your sensitive data or accounts—they need both pieces in order to log in, which makes it that much harder for hackers to get in.
The login flow might look something like this: when a user goes to log in, they'll first enter their username and password and then be prompted to enter a code we send them via SMS or voice call. So, even if someone had somehow compromised the user's password, they would still need the user's phone in order to log in for real.
The Twilio Verify API has a number of features to protect your app from fraudulent signups and to secure user accounts. Using all sorts of advanced fraud detection algorithms, Twilio can identify and prevent suspicious behavior, so problems never reach you and you don't have to waste time keeping unauthorized users at bay. That way you can focus on creating a great user experience without having to constantly monitor your accounts.
That's why when Verify is enabled, companies see big drops in account takeovers and fraud rates across the board. With features like Fraud Guard, you can analyze your traffic and block all traffic that appears fraudulent, or is different from what you normally see. The bottom line? We'll build a safer environment for your users to use, and you can sleep easy knowing that it's protecting their information.
Twilio's phone verification lets you send one time passcodes (OTPs) over any channel so you can reach your users how they want to be reached. Whether that's SMS, WhatsApp, or voice, your users can choose how they receive their OTP, so they can receive it how it's most convenient for them. This not only results in a better user experience, it also means higher OTP delivery rates.
And because people in other countries are different, Twilio lets you reach users how they want to be reached in more than 200 countries. So you can have just one app but in one country maybe you send OTPs over SMS, and in another country you might send OTPs over WhatsApp, so you can optimize OTP delivery for local norms, and have much happier customers and much less friction during the login process.
Compliance is hard, and only getting harder. But with Twilio's managed compliance, we've done the hard part for you. One reason to use Twilio Verify is to help you stay compliant with minimal effort. Which can be very useful if you're in a heavily regulated industry like finance or healthcare where there are a multitude of rules around keeping people's money and health safe.
The Verify API helps you stay compliant with A2P messaging rules, GDPR, and they'll even send you automatic updates and tips! Twilio does the work so you can rest easy knowing your product is legally squared away. So you don't have to worry about some random regulation coming out of left field to bite you later.
For developers, Twilio's Verify API is a one-time setup that you can drop in and test in minutes. It's so easy, developers can add phone verification to their app with minimal effort. With migration instructions, moving from Twilio's Programmable Messaging API to Verify API is seamless, and your app won't miss a beat.
Once you've set it up, you can enable features like Fraud Guard and multi-channel delivery with minimal additional effort. So you're not only saving time, you're not spending a lot of time building these sophisticated verification systems. Instead, you're building core features and perfecting the user experience. Which means businesses can move fast in the market, while still giving users a fast, secure, and easy authentication process.
You can use Twilio to verify phone numbers in minutes, and add an extra layer of security to your application. I'll show you how in this tutorial, and it'll be just one more way you can securely send verification codes and verify them.
Step 1 to set up Twilio phone verification: you need to create a Twilio account! This will give you access to Twilio's communication APIs. Once you've signed up, you can navigate to your Twilio console to find your Account SID and Auth Token. These credentials identify your application when you communicate with Twilio services. Keep them confidential. Anyone with these credentials can access your Twilio account and use your resources.
When you log into the console, you'll land on the dashboard. You can see your active projects, API usage, and manage your credentials. It's important to get this right because setting up your account is the first step to getting everything else right when you set up Twilio API services like sending a verification code to users.
Once you have your Twilio account credentials, the next step is to set up your development environment. This means setting up environment variables to securely store your Account SID, Auth Token, and Service SID so you don't hardcode sensitive information into your applications. You might use .env files with libraries like dotenv in Node.js, or something similar in other programming languages.
As well as setting up environment variables, you also need to install some libraries that will allow you to actually talk to the Twilio API. Depending on what your development stack is, you can use Twilio's official helper libraries which bundle up functions you can use for common things like sending verification codes. These libraries are what enable you to talk safely and easily to the Twilio platform from your app.
Once your environment is all set up, the next step is to create a verify service in the Twilio console. This service handles the lifecycle of verification codes. To create a service, go to the "Twilio Verify" section of your console. Here you can give your service a friendly name so you can recognize it easily.
While you're there, you'll also set the channels you want to use. Twilio can send verification codes over SMS, Voice, and even WhatsApp. By setting these configurations, you can give the end user a much better experience by letting them receive the verification code in whatever channel they prefer. Especially if you have an international or diverse user base, this will make sure that the most appropriate channel gets used for your specific users.
Now that you've set up your verification service, you can actually send a verification code. This involves making a POST request to Twilio's Verify API endpoint, and providing the phone number of the recipient, as well as the channel you want the verification code sent over.
You will need to format the phone number properly so that it is in E.164 and recognized across different countries. Depending on the channel you may also format your message with a custom template to make it even more clear and engaging. You may also prefix your message with a friendly and informative message so the recipient has an idea of what the code is for.
Once you've sent the verification code, you'll need to check the user input. To do this, you'll need to call the verify check API, passing the user input and the phone number of the user again. The API will check the input against the token it generated to make sure it's correct.
Getting success and errors right in this phase is important. When verification is successful, you can now grant the user more permissions based on that verified status. Conversely, if the input token is still incorrect after X attempts, or if the token has expired, your app needs to give the user the right feedback. Typically this will be an error message to inform the user of their next steps, e.g. that they need to request another verification code.
Finally, you'll need to handle successful verification responses, as well as common errors for incorrect or expired OTP submissions. Every verification response will be different, and thinking about them will help you help the user.
For example, if the user enters the code wrong, prompt them to try again, or to request a new one. If the code is expired, prompt them to explicitly request a new one. The right messaging will guide users and minimize confusion. Keeping them in the loop at each stage will reassure users and build trust in the security of your app.
When doing phone verification with Twilio, you want to do it in a way that you can secure your app without having to bother all your users with a bad experience. Here, we'll show you how to do phone verification the right way with Twilio so you can have a secure, user-friendly phone verification flow.
To ensure a successful verification process, one of the most fundamental asks is to validate phone numbers before you send them a One-Time Password (OTP). When you validate a phone number, you are confirming that it is in the right structure and format, and importantly, in the E.164 international numbering format. By incorporating validation checks, you can vastly reduce the error rate in your verification process and deliver OTPs more successfully.
For example, if a user enters a phone number that is incomplete or not in the expected format, the system should catch that and surface an error to the user before an OTP is sent. This pre-validation not only saves time and resources in fewer failed OTP attempts, but it also makes your user experience better. It's easier for the user, and you won't have as many users frustrated with guessing what format you want.
To protect your phone verification system from abuse, you'll want to employ rate limiting. Rate limiting is the regulations you put in place to dictate how frequently users can request OTPs. For example, allowing only 1 request per phone number every 30 seconds will deter bad actors attempting to flood your system with repeated requests.
This allows legitimate users to receive their verification tokens swiftly and easily, and protects you from potential Denial of Service (DoS) attacks. You can also get creative and implement more complicated regulations, like CAPTCHA challenges for users who exceed a certain number of requests in a time frame.
Ensuring users enter phone numbers correctly is key to a successful verification flow. A common sticking point for many is the E.164 format, which is a plus sign, then the country code, then the number. People won't need to Google it if you tell them the right number format, which is an easy lift to avoid errors.
In addition to format, you can use placeholder text to give an example phone number—this way people can see exactly what they should type into the field when they're filling out the form. A good balance of good UI and information will help avoid errors and lead to more successful verifications.
Monitoring success rates on an ongoing basis is key to creating a successful verification flow. Just by looking at verification attempt metrics, you can learn a lot about user behavior and common failure cases. When you combine that with feedback you're collecting—whether through surveys or through more direct user touchpoints in your app—you have a really complete view of what's happening.
If a lot of your users are failing verification, that might be an indication of bigger things at play, like SMS deliverability or the number-entry process. By iterating and perfecting your verification flow based on these learnings, you can realize a more secure, smooth, user-friendly experience.
While SMS is one of the most popular channels for phone verification, it's not always the most reliable. Users may not receive the SMS due to shoddy reception, or there may be a network issue with the provider and it won't deliver at all. That's why having other channels as a backup can be a huge asset to overall user experience, as well as overall verification success.
For example, if an SMS hasn't delivered after 5 attempts, you can give the user the option to "receive code via voice call" instead. They can click the button and receive their OTP through an alternate channel. Using multiple channels doesn't only accommodate user preference, but network issues for a more reliable, all-encompassing verification experience.
Developers tend to get hung up in a few places when it comes to setting up phone verification, and it's important to sort them out to deliver a seamless user experience and to communicate effectively with your end-users. Here's what some of those sticking points might be if you are using Twilio Verify.
One issue is that their texts are not getting through, usually due to carrier content filtering or phone delivery.
When you send an SMS, it is passed from carrier to carrier. Some carriers have strict content filters in place to protect their network. As a result, certain messages may be blocked if they contain certain keywords commonly used in spam or phishing. That means that even though you're a legit message, your message may not make it to the intended recipient because it is blocked!
The other reason you might not be receiving messages is your phone. If your phone is off, out of service, or your carrier doesn't support receiving from certain sources, messages won't be delivered. You can look at the message logs from the Twilio console to see the delivery status, and whether the messages are received, undelivered, or failed.
Twilio APIs can produce a client-side 4XX error. Client-side errors make up 99% of all 4XX errors you encounter and are almost always the result of an issue with your API request parameters or failing to meet the API spec. You'll need to be able to recognize Twilio error codes to know where to start looking; each code tells you a little about what's gone wrong.
For instance, '400 Bad Request' probably means you've sent some invalid data, while '401 Unauthorized' probably means there's something wrong with your authentication (like you have an invalid Auth Token). By looking at the error response and referring to the API documentation, you'll be able to narrow in on the problem area and correct your request to maximize your messages' deliverability.
Sending SMS messages across borders is a nightmare. Each country and carrier has their own peculiar rules and limitations and you'll run into all sorts of weird and surprising issues with getting your messages delivered. It could be because of how your number is configured and that's because of the carrier sending the message, or it could be because of how the network is set up in the recipient's local country, or it could be something else entirely.
You'll need to know your carriers' limitations. If your messages aren't getting through when they cross borders, you'll need to work with the carrier that is handling the outbound SMS to figure out what their limitations are. A lot of times, you'll need to enable some feature or tweak your Twilio account in a particular way to get international to work properly.
If a user tells you that they aren't getting their verification codes, it's possible that they've blocked SMS. There are many services that allow users to manage how they receive messages, including the option to block SMS. That means when we attempt to send a message, we'll receive an error response telling us the user has blocked messages.
To resolve this, we need to direct users to check their SMS opt-in status. If message blocking is enabled, they may need to send "START" or "YES" to begin receiving messages again.
Repeated messages might mean that your application is POSTing to Twilio multiple times and getting into trouble. If your application POSTs many times to Twilio in a short timeframe, the user may receive the same /twilio/verify phone number verification code more than once which may be confusing and erode user trust in your application.
When debugging, you'll need good logs for each request you make to Twilio. You'll want to check the Messaging logs to see if and when messages were sent. If they were sent close together, you'll need to debug the logic of how you send your SMSes, so that your user always receives a verification code in a timely manner. Add more protections, so that you don't send too many messages to a single verifier.
Twilio Verify Phone Number is an easy way to verify phone numbers for user verification and authentication. Make sure your users are real and reduce fraud with a one-time passcode (OTP) sent by SMS, voice call, or email that's easy for users to confirm. With more than 4.8B verifications performed each year, Twilio is the most trusted way to keep your users human. This can help you stay compliant, but it can also drive your conversion rate up and make your user sign-up flow easier. You can get started easily and monitor how effectively people are verifying their phone numbers. There are a few things you can do to ensure users aren't gaming your phone verification system, such as validating the phone number, rate limiting the number of OTP requests, using multiple channels to send the OTP, and more.
Twilio Verify Phone Number is an API that allows you to add phone verification to your user authentication flow so you can confirm that the phone numbers associated with an account are real and under user control, for enhanced security and improved user experience as sign up and account management become more dependable.
Twilio Verify helps stop fraud by authenticating phone ownership, making it harder for someone to pretend to be you and take over your account. The one-time passcode (OTP) acts as an added layer of security, now requiring not only the user's credentials but also the phone number provided by the user to log into the account.
Twilio Verify helps you meet government requirements and standards for user authentication and data protection. You'll have the tools to handle user data responsibly and maintain compliance with industry regulations—an important step in garnering customer trust, especially when people are more concerned than ever about their data.
Key features include a multi-channel OTP delivery system (SMS, voice, email), high reliability with billions of verifications processed annually, fraud detection capabilities, 2FA support, and an easy setup process for developers.
To use Twilio Verify, developers will need to sign up for a Twilio account and receive their credentials, set up their environment to store them securely, create a verification service in the Twilio console, and then make API calls to send and check OTPs, handling responses and errors.
Validating phone numbers helps to ensure they are in the right format and are real, which helps avoid failed OTP deliveries. This pre-validation makes the verification process more efficient, for a better user experience and cost savings.
Good ideas include validating phone numbers before sending OT#s, rate limiting to prevent abuse, strict instructions for proper number formatting, monitoring verification success rates, and having backup channels for OTP delivery.
Other common barriers are undelivered messages due to carrier filtering, debugging API response errors, understanding international SMS limitations, managing SMS preference per user, and combating duplicate message issues from multiple requests.
Twilio allows you to choose the way you deliver the message -- over SMS, voice call, or email. Which is great because people can have a really good user experience and get their OTP securely sent to them regardless of their user demographic or accessibility needs.
Two-factor authentication is an important tool for keeping your online accounts secure. It's a second layer of security that combines something you know (like your password) with something you have (like a one-time passcode sent to your phone) to help protect your account. That extra layer of security makes it much harder for hackers to get into your accounts.
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