Voice OTP for 2FA | Bulk Voice OTP Gateway | Exotel

Guaranteed customer verification with a secure Voice OTP Service

Create a failsafe two-factor authentication (2FA) process with voice.




Trusted By

cloud telephony - south east asia - exotel
cloud communications

Asha Satapathy

Exotel’s SMS delivery rate is quick. We have observed an improvement in our customer experience after using Exotel.

Founder & CEO, DocEngage

Raju Pardeshi

We’ve been using Exotel since BookRyde’s first baby step. It has really helped us implement and run SMS solutions seamlessly.

Founder & CEO, BookRyde

Apurv Jain

Exotel helps us in the entire packaging of the SMS reminders channel, thereby leaving the user delighted, satisfied, and retained with Haptik.

Product Manager, Haptik

Praveen Chandran

Our level of efficiency has drastically increased ever since we’ve started using Exotel. It’s increased by at least 3X.

Product Head, Quikr Services, Quikr


What is a Voice OTP?

A voice OTP (one-time password) is delivered over an automated voice call to enable two-factor authentication. It is usually used in case the delivery of an OTP SMS repeatedly fails. A customer can also trigger generating an OTP Voice during the OTP verification process.

Why Exotel?

Unbeatable Platform Uptimes 

Our platform delivers upto 99.94% uptime – this includes operator uptimes


Superior Quality

We offer best-in-class call success, voice quality and limited latency rates in the market.

Highly Flexible

Our REST APIs make custom integrations a breeze with your enterprise systems. 

Scale at Ease

You do not have to worry about seasonal spikes in OTP requests. We scale our service without you having to worry about infrastructure limits.

Simple to Implement

Our platform’s user-friendly and straightforward interface allows you to get started in less than 30 minutes.

Leading Security Standards

Our platform is end-to-end secured through the ISO 27001:2013 certified information security management system.

Best Support

24×7 customer support via phone, email and Twitter. In fact, when you call, we use our platform to give you the best service experience.

Real-time Reports

Know performance levels of your Voice OTP campaigns through metrics like pick up or unanswered call rates.

How can businesses use Voice OTP?


To allow third-party access like permitting delivery agents into secured communities, Voice OTP plays a crucial role.


For highly secure transactions like access to net banking or signing up for your product or service, use voice OTP verification.

Transaction Verification

Protect your customers from financial fraud by authenticating transactions of any value with a Voice OTP service.


Safely allow your customers to regain access to your service after an email address or password change using Voice OTP.

Account Reactivations

Win new business back from the right customers through a secure IVR OTP sequence to restart their services with you.

Beyond Passwords

Offer a faster, yet safe login experience by considering OTPs over passwords as a real-time authentication process.

Benefits of using Voice OTP


Voice Failover

Add a failsafe layer over the default OTP SMS step. When delivery fails, ensure 100% delivery with the OTP converted to speech and sent over a call.


Instant Call Connect

With a platform offering high service uptime, trigger a voice OTP verification call within a few seconds and improve customer engagement scores.


Easy & Flexible Integrations

Set up campaigns with easy-to-use Voice OTP & SMS APIs that connect with your enterprise software like an ERP.


Personalise Call Formats

Offer easy-to-configure IVR OTP calls through the platform’s dashboard. Include brand mentions or a sales offer to boost sales.


Track Campaigns

Gauge campaign performance by pulling reports from the platform’s dashboard or API. Test different strategies to improve results.

How customers use our SMS Solutions

Swiggy used Exotel’s automated calls to reduce manual work and delivery delays

Read More

Ola uses Voice APIs to connect drivers to customers

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Automated SMS reminders contributed to 40% of Haptik’s customer retention results

Read More


What is a Voice OTP?

It is a 2-factor authentication feature that generates an OTP and converts it to a voice message through text-to-speech technology. Delivered through an automated call, It is used to securely validate customer's interactions with a businesses' digital portals.


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What is an IVR OTP?

An IVR OTP is a one-time password issued by a business to make transactions through the Interactive Voice Response (IVR) mode.


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How can I get an OTP on a call?

OTPs are usually delivered through a call in cases where SMS delivery fails. Or when a customer simply prefers to receive the OTP over a call, voice OTP verification can be used. Exotel can fetch the OTP generated by your backend system and deliver it over a call.


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Which are the best two-factor authentication methods?

SMS and voice are the most commonly used methods, along with hardware keys or authenticator apps like Microsoft or Google Authenticator.


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What are the advantages of a Voice OTP service?

A Voice OTP service uses a channel that is more secure than SMS as the sequence of digits is heard only by the customer over a call versus an SMS visible in Messages. In some cases, the call reaches the customer faster than an email or a text OTP would.


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Automated Calls vs SMS Reminders why calls win

Automated Calls vs SMS Reminders: Why calls win

Millennials might prefer SMS over calls, but statistics prove that when it comes to reminders, calls reign supreme.This white paper helps understand the unique ways in which automated calls can be used for reminders.

Find out how Exotel can work for you. Set up a call.

We take away some of the biggest pain points of traditional systems like EPABX.


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