How to Send OTP SMS Texts With Dexatel's Verify API

Traditionally, applications ask users for a login and password to authenticate accounts. However, this method is no longer considered secure.

One initial problem users face is creating and setting strong passwords. They might carelessly write credentials on sticky notes or save them on other devices. Additionally, hacker attacks can break password-based systems and access corporate data. To enhance security, an extra layer of protection is necessary.

Nowadays, applications send one-time passwords (OTP) via SMS for user authentication. 

SMS OTP verification is also used during the user registration process to verify phone numbers while creating accounts. This method proves account ownership via a phone number. A randomly generated unique code is sent to the user’s phone, which they must enter for authentication. One-factor authentication (1FA) requires only a password or a code received on the phone.

A more secure approach is multi-factor authentication (MFA), which requires multiple pieces of information, such as a password and a code. Two-factor authentication (2FA), a type of MFA, asks users to provide a code received via message along with their username or password. Requiring two pieces of information, 2FA prevents identity theft by using a code that can only be used once.

Dexatel's SMS API delivers phone-based SMS authentication codes within a limited duration.

Implementing user verification via phone number has several benefits for businesses. First, verifying mobile numbers adds an extra layer of security, reducing fraudulent activities. The Verification API sends an automated text message to the subscriber’s phone number for verification, ensuring that the account holder is a real person. Second, phone number verification protects against spam and multiple account creation, as each phone number is associated with one user. Third, you obtain a database of verified mobile numbers, allowing you to contact clients whenever needed.

All these tasks are easy to accomplish with Dexatel's Verify API.

Send OTP Messages Globally With Dexatel Verify

Secure user authentication through a verification platform built for speed, reliability, and global reach. Dexatel Verify enables businesses to deliver OTPs through SMS and other verification channels while managing authentication workflows from a single platform. Intelligent routing, real-time tracking, and flexible API integration help maximize verification success rates and improve the user experience. Whether you're onboarding new users, securing account logins, or approving transactions, Dexatel Verify helps automate authentication at any scale.

Key Features of Dexatel's Verify API

SMS OTP Delivery

Deliver one-time passwords through a reliable global SMS infrastructure built for authentication workflows. Dexatel Verify uses intelligent routing and carrier-connected delivery paths to help maximize OTP delivery rates and minimize verification delays. This makes it easier to support secure user authentication across different countries, carriers, and devices.

WhatsApp, Viber, and Voice OTP Support

Go beyond traditional SMS verification by delivering OTPs through multiple communication channels. Dexatel Verify supports WhatsApp OTP, Viber OTP, and Voice OTP, allowing businesses to reach users through their preferred channels. Multi-channel verification also helps improve authentication success rates when SMS delivery encounters challenges.

Automated Code Generation

Generate secure, unique verification codes automatically without building custom authentication infrastructure. Dexatel Verify handles OTP creation and delivery as part of a streamlined verification workflow, reducing development complexity and accelerating implementation. Businesses can focus on user experience while the platform manages the verification process.

Configurable Expiration Windows

Control how long verification codes remain valid based on your security requirements and use case. Flexible expiration settings help reduce the risk of code reuse while allowing businesses to balance security and usability. This makes it easier to tailor authentication workflows for different customer journeys and risk levels.

Real-Time Verification Status

Monitor every stage of the verification process through real-time status updates and reporting tools. Businesses can track OTP delivery, verification attempts, successful authentications, and failed requests from a centralized platform. This visibility helps teams identify issues quickly and optimize authentication performance.

Fraud Prevention Controls

Protect authentication workflows with built-in safeguards designed to reduce abuse and suspicious activity. Features such as rate limiting, retry restrictions, behavioral monitoring, and verification controls help prevent brute-force attacks and fraudulent verification attempts. Additional security layers can be applied to high-risk user actions and transactions.

API and Dashboard Management

Manage verification workflows through flexible APIs or a user-friendly dashboard. Developers can integrate authentication directly into applications, while operational teams can monitor performance, review verification activity, and configure settings from a centralized interface. This combination of technical flexibility and administrative control helps simplify authentication management at scale.

Why Companies Choose Dexatel's Verify API

Global Coverage

Reach users around the world through a verification platform designed for international authentication. Dexatel Verify supports OTP delivery across a broad network of countries, carriers, and mobile operators, helping businesses maintain consistent verification experiences regardless of user location. Global carrier connectivity and routing optimization help improve delivery performance across diverse markets and network environments.

Intelligent Routing

Successful authentication depends on more than simply sending a message. Dexatel Verify uses intelligent routing logic that evaluates carrier performance, network availability, destination requirements, and delivery conditions to select the most effective path for each verification request. This helps reduce delays and improve overall verification success rates.

High Deliverability

OTP messages must arrive quickly and reliably to support secure authentication workflows. Dexatel Verify leverages carrier-connected infrastructure, delivery optimization, and routing redundancy to maximize delivery performance across global networks. This helps businesses reduce failed verifications and improve user onboarding and login experiences.

Multi-Channel Authentication

Verification is not limited to SMS alone. Dexatel Verify supports multiple authentication channels, including SMS OTP, WhatsApp OTP, Viber OTP, and Voice OTP, allowing businesses to build flexible verification strategies. Multi-channel support also enables fallback workflows that help maintain authentication success when a preferred channel is unavailable.

Fast API Integration

Integrating authentication into existing applications should not require lengthy development cycles. Dexatel Verify provides developer-friendly APIs, SDKs, and implementation resources that simplify deployment across websites, mobile apps, and backend systems. Most businesses can begin testing and launching verification workflows in a relatively short timeframe.

Real-Time Analytics

Gain complete visibility into authentication performance through detailed reporting and monitoring tools. Businesses can track delivery rates, verification attempts, completion rates, and channel performance in real time. These insights help identify issues quickly and support ongoing optimization of verification workflows.

Dedicated Support

From onboarding and implementation to scaling and optimization, Dexatel provides access to experienced support specialists. Our team can assist with integration questions, authentication best practices, delivery troubleshooting, and workflow optimization. This helps businesses maintain reliable verification performance as their user base and authentication volume grow.

How to Integrate Dexatel’s Verify API to Send OTP SMS Messages

Create an Account

• Sign up for a free account on the Dexatel platform.
• Log in to your dashboard to manage your account settings, such as topping up your balance and updating information.

Generate a Unique API Key

• Navigate to the API Keys section.

The system will generate a unique API key, which you will use to send automatic requests on your behalf.

Create a Sender Name

• Add your brand name to the Sender IDs, use your shortcode, or choose a new one in the dashboard.

Alternatively, you can send a POST request to the Sender endpoint to send OTP messages with a customized ID.

Get a Template ID

• Go to the Templates page or send a POST request to the Template endpoint.

Once a template is created, the API will generate a template ID for you to use. You can also send a GET request to the Templates endpoint to retrieve your template ID. When creating a template text, make sure to include a {code} variable in it.

The Dexatel Verify API will generate a random OTP and replace the {code} variable in your message.

Example SMS Verification Templates

• Your dynamic code is {code}. Do not share it with anyone.
• Your verification code is {code}. Complete the verification as soon as possible.
• Your registration code is {code}. Thank you!

Verify Your Clients’ Phone Numbers

• Request your clients' phone numbers to verify their ownership by sending an SMS code.

If the code matches, the verification process will be completed. If the code does not match, it will expire, and the user will be temporarily blocked after three unsuccessful attempts.

How It Works

When your client provides a phone number for verification purposes, such as to make a payment, your application sends a POST request to the Verification API endpoint.

Here's an example of how to do this:

Endpoint: v1/verifications

Headers:

• X-Dexatel-Key: {Your Unique Key}
• Content-Type: application/json

Example POST Request

json
Copy code
{
  "data": {
    "sender": "Your Sender Name",
    "phone": "Your Client’s Phone Number",
    "template": "Your Template ID",
    "code_length": "Length of Code"
  }
}

Upon receiving the request, the Verification API creates a unique code with the specified length as the value for the code_length parameter.

It then sends a message to the phone number specified in the phone parameter. Make sure to specify the template ID for the template parameter in your request. The Verify API will use the template corresponding to that ID and replace the {code} placeholder in the message with the generated OTP.

Verification Process

Sending the OTP:

• The client receives an SMS message containing the OTP.
• The message is formatted according to the specified template, with the {code} placeholder replaced by the OTP.

Entering the OTP:

• The client types the OTP into your application.

Validating the OTP:

• Your application sends a POST request to the Verification API endpoint with the entered OTP.
• The API compares the entered OTP with the one sent to the client.

Possible Outcomes

Successful Verification:

• If the OTP matches, the client is successfully verified.

Failed Verification:

• If the OTP does not match, the client will not be verified.
• If the client fails to enter the correct OTP within the specified time frame, the OTP will expire.
• The system can regenerate a new OTP upon receiving a new POST request from your application.

Multiple Failed Attempts:

• After several unsuccessful attempts, the client may be temporarily blocked.
• The client can request new OTP SMS codes only after being unblocked.

This process ensures secure and efficient verification of your client's phone number, adding an extra layer of security to your application.

Common Use Cases of SMS OTP Verification

User Registration

Verify phone numbers during account creation to ensure that new users provide valid and accessible contact information. OTP verification helps reduce fake registrations, prevent automated account creation, and improve the overall quality of user data. By confirming identity at the onboarding stage, businesses can establish a stronger foundation for account security.

Login Authentication

Strengthen account security by requiring users to verify their identity during login. OTP-based authentication adds an additional layer of protection beyond usernames and passwords, helping reduce the risk of unauthorized access. This approach is commonly used as part of multi-factor authentication (MFA) strategies.

Password Recovery

Allow users to securely regain access to their accounts when they forget their credentials. OTP verification confirms ownership of the registered phone number before a password reset is completed, helping prevent unauthorized recovery attempts. This creates a more secure and user-friendly account recovery process.

Transaction Approval

Verify user identity before processing payments, transfers, withdrawals, or other high-risk transactions. OTP authentication helps ensure that sensitive actions are approved by the legitimate account owner, reducing the risk of fraud and unauthorized activity. Many financial institutions and eCommerce platforms use OTPs as part of their transaction security workflows.

Device Verification

Confirm user identity when a login attempt originates from a new or unrecognized device. OTP verification helps businesses validate device ownership before granting account access, reducing the likelihood of account compromise. This additional security layer can be implemented without creating significant friction for legitimate users.

Account Recovery

Support secure account restoration when users lose access to a device, change phone numbers, or encounter account-related issues. OTP verification provides a reliable method for confirming identity before restoring access to sensitive account information. This helps balance account security with a smooth recovery experience for legitimate users.

Start Sending OTP Messages With Dexatel Verify

Reliable OTP delivery plays a critical role in protecting user accounts, preventing fraud, and creating secure authentication experiences. Whether you're onboarding new users, verifying logins, approving transactions, recovering accounts, or implementing multi-factor authentication, Dexatel Verify provides the tools and infrastructure needed to automate verification workflows at any scale.

With global delivery capabilities, multi-channel verification options, real-time monitoring, and developer-friendly integration tools, businesses can build authentication systems that are both secure and user-friendly. Dexatel Verify helps organizations improve verification success rates while reducing operational complexity and maintaining a seamless customer experience.

Start building secure, scalable OTP verification with Dexatel Verify today.

Frequently Asked Questions

How quickly can I integrate Dexatel Verify?

Most businesses can integrate Dexatel Verify within a few hours using our APIs, SDKs, and implementation guides. The exact timeline depends on your application architecture and authentication requirements, but the platform is designed to simplify deployment and accelerate time to market.

Can I send OTPs through channels other than SMS?

Yes. In addition to SMS OTP, Dexatel Verify supports authentication through channels such as WhatsApp, Viber, and Voice OTP. This allows businesses to build multi-channel verification workflows and reach users through their preferred communication channels.

What happens if an OTP message is not delivered?

If an OTP cannot be delivered successfully, businesses can implement fallback strategies using alternative verification channels. Multi-channel authentication helps improve verification completion rates and reduces the risk of users abandoning the authentication process due to delivery issues.

Can I customize OTP templates?

Yes. Businesses can create and customize OTP message templates to align with their branding, communication requirements, and user experience goals. Templates can include dynamic placeholders for verification codes and other variables while maintaining a consistent messaging format.

Does Dexatel support international OTP delivery?

Yes. Dexatel Verify supports OTP delivery across a global network of countries, carriers, and mobile operators. International coverage, intelligent routing, and carrier-connected infrastructure help businesses provide reliable authentication experiences for users worldwide.