Verify Users with SMS & Voice One-Time-Passwords

Our two-factor-authentication (2FA) API enhances data & application security & delivers OTPs via SMS, Voice, & Push message.

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One Time Password

What is a One Time Password (OTP)?

One Time Passwords (OTP)​ are a form of two-factor-authentication (2FA) that are generated as a string of characters or numbers. OTPs are sent to a user's mobile device via SMS or Voice which is then used to verify the user's identity in order to protect online applications & data.

Secure your business and accounts with One Time Passwords

Online security and data protection is critical in this modern world and has become a key priority for digital businesses. Two Factor Authentication is an additional layer of security to overcome the vulnerabilities of a standard password and is essential to keeping your company and its data protected. 

One Time Passwords are an easy and reliable form of 2FA, and are used to add a second layer of authentication. The risk of fraud is drastically reduced if the user doesn’t only have to fill in his user name and password. OTP messages are unique to every single user and every single login on any digital device. 

  1. Guaranteed delivery's One Time Passwords can be delivered via SMS or Voice. By choosing or combining both channels delivery is guaranteed at all time.

  2. API integration

    With the OTP API from you can generate One Time Passwords, deliver them via SMS or Voice and verify the response.

  3. All in one platform

    Through our platform, you'll be able to use SMS and Voice also for other purposes. Joining gives you access to all our mobile solutions.

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Comprehensive solutions for Two Factor Authentication

Quick delivery of OTPs via SMS or Voice

Authenticate new users

Let new users verify their phone to prevent spammers and bots from access to your platform and rule out bulk account creation.

Secure account logins

Protect your platform and accounts from data theft and let users sign in with an OTP via SMS or Voice messaging at each attempt.

Safeguard transactions

Add an extra layer of security by implementing an OTP to verify accounts before users proceed with a transaction.

One Time Passwords via SMS

With a 98% open rate within 30 seconds, SMS is known for its high reliability. By sending One Time Passwords via SMS, you are sure to reach your users wherever they are.

Even when users don't have access to the internet they can still use this multi-factor authentication solution.

  1. Number validation

  2. Fast and reliable delivery

  3. Send from a local phone number

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one time password sms

One Time Passwords via Voice

An alternative to SMS is Voice. With Voice, the spoken password is received as a phone call on the user's mobile. The password will not be stored on the user's phone and Voice allows you to reach users with limited sight. You can also implement Voice as a back-up in case your SMS is not delivered. 

  1. Global reach and reliability

  2. Different spoken languages

  3. Delivery rates pushed close to 100 percent

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one time password voice message

SMS & Voice One-Time-Password Pricing Plans

Flexible Pricing for SMS & Voice OTPs


*Per Authorization

SMS or Voice OTP


*Per Authorization

SMS or Voice OTP


*Per Authorization

SMS or Voice OTP


*By Volume & Overage

SMS or Voice OTP

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Benefits of Using a One Time Password

OTPs will minimize the risk of fraudulent login attempts and come in all shapes and sizes, but always add an extra layer of authentication. The risk of fraud is drastically reduced if the user doesn’t only have to fill in his user name and password (something he knows) but also needs something he “has” to complete the login.

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Customer Success Stories has continued to provide high-quality and reliable SMS technology and services for companies of all sizes. Learn how our OTP API enables easy, secure and safe access and logins for both consumer and seller.

OTP for developers -
Easily integrate our OTP API offers a reliable and secure One Time Password solution that can be delivered to any mobile phone via Voice or via our reliable high quality SMS routes. Our OTP solution build consumer trust and increases your conversion across multiple channels.

Use one ready-made API to implement into your software and offer intelligent and secure authentication to protect your users and your data. Use our developer documentation and send your OTPs worldwide.

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one time password api

Why choose

GDPR compliant Enterprise Messaging

Worldwide delivery under 10 seconds

Our pro-active monitoring guarantees fast delivery of time critical messages in high volumes. Delivery rate and speed is constantly measured by live test results.

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Direct mobile operator connections

Our platform is connected to 2000 operator networks in 200 countries. This means that you can benefit from high quality routes at the best price.

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Secure and reliable, 24/7/365 Support

With high uptime and a redundant setup, you can rely on our highly secure and ISO 27001 certified platform with 24/7/365 support from our Network Operations Center.

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Realtime analytics, detailed insights

Our powerful Analytics tool gives you a real-time and detailed overview of your worldwide traffic so you can track, trace and optimize flows.

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