2 Factor Authentication

with SendOTP

Mobile number verification, 2-factor login, voice backup call,
OTP protected transactions with enhanced security and speed.
Group 17307@2x

SendOTP 2.0

with invisible verification

Enable authentication with invisible verification
The magic happens when OTP gets auto verified.
Just integrate and let the magic begin.
(Currently available in India)
  • Platform
  • Success Rate
  • Verification Time


  • SMS + Voice
  • 99%
  • 8 seconds

Regular OTP

  • Works with SMS
  • 95%
  • 10 seconds

How it works

A comprehensive solution for 2FA

Pin Generation

Our platform provides the back-end logic needed for PIN generation (OTP) so you don't have to.
Each code is tied to an individual user and can only be used once.

Number Lookup

Save money and increase conversation rates with our number validation. We're able to catch invalid numbers as they're entered, making sure your message is headed to a valid number.

Voice Failover

Voice-based 2FA adds text-to-speech capability to the standard 2FA process, enabling you to place calls and deliver user authentication PINs via voice audio. By adding voice failover message delivery rates can be pushed close to 100 percent.

Global Coverage

Deliver your authentication PINs to users regardless of their location. With MSG91 global coverage spanning 800 networks and 190 countries, you can deliver your one-time PINs with best delivery rates and speed available on the market.

5 minute setup

We made enabling 2-factor authentication a cake walk!

Secure your Website/App in 2 minutes by 2FA (mobile verification).


Ask us anything!

An OTP verification is a part of the two-factor authentication encryption system established for user safety. By asking a user to verify OTP online, this application reduces the risk of accounts and details being accessed by malicious parties, securing private data, and protecting bank account details during online payments. OTP verification helps businesses by reassuring their customers of their online security measures, thus increasing brand reliability.

To verify an OTP, you simply have to type the code received via SMS into the slot as required by the website or application. If the code is correct, you will gain instant access to continue your transactions. If in any case your OTP is not received or you fail to enter it within the stipulated time (usually 30-45 seconds within OTP generation), you can request a new one by clicking on the “generate new OTP” icon below the OTP field on your screen. Some websites and applications have an automated internal OTP verification system that reads your OTP from the SMS received (permission needs to be granted) and auto-verifies your authenticity.

For Business: To get OTP by SMS, you have to sign up to an OTP service provider such as MSG91’s SendOTP. Unlike regular OTPs, SendOTP has a success rate of 99% with a verification time of fewer than 8 seconds. The application will help you generate unique and time-bound OTPs for your clients on their mobile number to conduct two-factor authentication (2FA) protocol before gaining access to your website or application.


For User: To receive an OTP by SMS, you have to enable two-factor authentication and request a one-time password from the application or website you want access to by entering your registered mobile number and clicking on “Send OTP”. You will receive an OTP within seconds on your SMS inbox.

An OTP application is one that is used to generate and send OTP to the users of your online website, payment gateway or services. These applications use an online OTP generator to verify the authenticity of the users of such clients by using back-end logic to create a code, so you don’t have to. Big enterprises usually have an inbuilt SMS OTP verification service, but those who do not, employ the services of an OTP platform like MSG91. In a matter of minutes, one can set up their account to send Voice OTP and SMS OTP to users for secure verification!

Generating an OTP is a back-end cryptology process performed by an online OTP generator. The most common method for the OTP generation as defined by The Initiative For Open Authentication (OATH) is the Time Based One Time Passwords (TOTP). This is a Time Synchronized OTP, in which time is the cardinal criteria that is used to generate a unique password. The password generated is created using the current time and it also factors in a secret key. Instances of this type of OTP generation are Time Based OTP Algorithm (TOTP) and a few mathematical algorithms that use the previous OTPs to generate new ones.