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). Advantages of 2 Factor

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.
Abhinay Saxena
Abhinay Saxena
13 March 2023
I recently used the Fortius toll free number service and was extremely satisfied with the results. The customer service team was highly responsive and answered my call within one ring. They were very courteous and provided me with the information I needed in a prompt manner. I found their staff to be knowledgeable and professional throughout the entire process. The service provided was invaluable and I would certainly consider using them again in the future. Highly recommended!
Pranjal Srivastava
Pranjal Srivastava
11 March 2023
I recently used Fortius Infocom's Bulk SMS service and it was amazing! The user interface was very intuitive and user friendly. I found it very easy to get started and the process was smooth. The delivery of messages was fast and accurate. Overall, I had a great experience with the service and would definitely recommend it to others.
Komal Ks
Komal Ks
10 March 2023
I recently used a bulk SMS service for my business and I have to say that I'm really happy with the results. The service was efficient and easy to use, allowing me to send out messages quickly and easily. It was also very reliable, as the messages were always sent out on time. Overall, it was a great experience and I would definitely recommend this service to anyone looking for a way to quickly send out messages in bulk.
Akash Singh
Akash Singh
9 March 2023
I recently tried out a bulk SMS service and I was pleasantly surprised with the ease of use and the quality of the service. The customer support staff was incredibly helpful and responded to my queries quickly. The delivery rate of the messages was very good and I was able to reach out to a large number of people almost instantly. The interface was also easy to use and navigate, making it a breeze to send out my messages.
Abdul Rehman
Abdul Rehman
8 March 2023
I recently discovered Fortius Voice call service and I am so glad I did! The clarity of the calls is outstanding and it's the perfect solution for any business. Whether you're on a call with a client or a team member, the sound quality is exceptional. What's more, their competitive pricing makes it so easy to fit into any budget. I highly recommend this service and can't wait to see how it helps my business grow!
7 March 2023
I'm so glad I found Fortius Infocom for my business! Their toll-free number service is reliable and user-friendly. Their customer service team is always available to answer any questions I have, and they are very knowledgeable. I highly recommend their services to anyone looking for a reliable and affordable toll-free number service provider.
Adnan Ali
Adnan Ali
6 March 2023
I recently used Fortius Infocom's bulk SMS service and I was so impressed. They provided excellent service and support throughout the whole process, which made it a breeze. The turnaround time was really fast, and the quality of their products was top notch. I highly recommend this company for anyone who needs to send bulk SMS messages!
Shobhnath Keshri
Shobhnath Keshri
5 March 2023
I recently purchased a product from Fortius Infocom, and I am impressed with their customer service and support. The staff was very helpful in answering my questions and providing information on the product itself. They clearly had a thorough understanding of their products, which made me feel confident in my purchase. They also provided clear instructions on how to use the product, which made it easy to get started. Overall, I am very pleased with Fortius Infocom's support and services both were outstanding.
Praveen Srivastava
Praveen Srivastava
4 March 2023
I recently used Fortius Infocom for bulk SMS services and I'm extremely pleased with the results. The support team was incredibly helpful and knowledgeable every step of the way. I felt confident that my project was in safe hands. The entire process was seamless and the delivery of messages was prompt and accurate. Highly recommended!
3 March 2023
I recently hired Fortius Infocom for a bulk SMS campaign and I am really impressed with their services. They provided me with a quick response, reliable support and valuable advice. Their team was very professional and knowledgeable about the industry. I'm really happy with the results we got from the campaign. The process was smooth and easy to use. I would definitely recommend them to anyone looking for quality bulk SMS services in Lucknow!
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