bulk sms call

OTP Voice SMS or Bulk OTP Voice Calls is used to verify a mobile number. This verification is done by making a call to the mobile number & playing a sequence of digits.

Guaranteed delivery of sensitive and critical information like OTP via our Voice Call OTP Service. Voice call-based OTP is a two-factor verification tool that authenticates and allows businesses to facilitate API based OTP generation for its potential clients.

Our premium and trusted notification solution ensures 100% delivery of sensitive and critical information on any mobile number of India. You can send OTP (one-time passwords), login passwords, transaction alerts, and other alerts as well.

With the help of our voice call OTP API multiple industries are getting benefits like Banking institution, Accounts and Financial institution, Share and broker firms.


What exactly is Voice Call OTP and how does it work?


The Voice OTP method enables you to authenticate using the OTP that is sent through the phone call to your registered phone number. You can use this OTP for authentication within a short duration. When you try to authenticate on any device, the specified OTP is compared with the OTP generated on the server.

The concept is pretty simple – User login. Users enter account information on applications/websites of businesses. …

System sends password. The system handles requests and makes calls toward customers’ mobile phones. …

Users enter the verification code and log in the system. The user enters the OTP on the mobile app/website.



What is 2 Factor Authentication via Voice Call OTP?

Communications service providers can enable secure transactions for enterprise clients using two-factor authentication (2FA) with voice. The most widely implemented solution for strong authentication is undoubtedly 2FA also known as one-time password (OTP). 


Authentication via Voice Call OTP.


  • Password-less Authentication.
  • Low operational cost.
  • Cheaper than OTP SMS Authentication.
  • Not any text record anywhere.
  • Simple and secure HTTPS API based integration with your applications.


Here are Five user management best practices where mobile phone verification can increase security through Voice OTP and boost customer acquisition and retention:


  • Authentication

Add an additional layer of security to your e-Commerce website, software, without increasing the complexity for users. Authenticate registrations with Voice Call OTP Verification.


  • Authorization

Send text to speech be it account deletion, restoration or activation, use Voice Call OTP Verification to be sure that your customer data remains secure. Use a premium Voice Call OTP service now.


  • Transaction Validation

Make all transactions safe and sound. Add an extra fold of security with OTP verification to complete a transaction securely. Start validation of all transactions now!


  • Reactivation

Reactivate a client account with a confirmed acceptance from them. Use OTP verification code as a means of obtaining permission.


  • Reset

Instead of sending links or verification code via email, use the OTP service to verify users before password resets.




You need to avail Voice Call OTP Service.

Integrate our 2 Factor Authentication API.


Why Choose Fortius?

No setup cost | No license cost | No Monthly cost | Free API | Unlimited Validity


API Work Flow

Our API handles all the authentication infrastructure. We have written a detailed documentation on 2 Factor Authentication via Voice Call OTP which you can forward to your development team.

Step 1: Hit our API with details such as user mobile number, OTP code and other parameters.

Step 2: Upon Success response, flash the OTP Text Box to your user.

Step 3: User receives a call and listens to a Verification code.

Step 4: Users will enter the verification code in the OTP Text Box.

Step 5: Compare the API verification code with the otp text boss’s verification code. if you get the right code then your user is authenticated.

Step 6: Take your authenticated user for further transactions.

Note: All parameter is mandatory and please don’t repeat OTP Code.


API Document




<string xmlns=”http://schemas.microsoft.com/2003/10/Serialization/”>Success# 637587426642009123</string>


Parameter Information:
Parameter Name Description
apikey Given on users Voice Call OTP accounts.
callerId The number from which the user will get the call. This will be given to you by us.
mobileNumber User’s mobile number.
fileName Audio file that you want to play with OTP.
otp Your verification code.
Copyright © 2023 Fortius Infocom (P) Limited. All Right Reserved
Fortius Infocom Private Limited
H. No. : 1st Floor 4/167 Vibhav Khand, Gomti Nagar
Uttar Pradesh 226010
Phone: +91-8114168888
Go to top