Leading OTP SMS Platform for Businesses | Exotel

Use case

Reliable OTP SMS Service

Implement two-factor authentication with SMS.




Trusted By

cloud telephony - south east asia - exotel
cloud communications

What is an OTP SMS?


OTP SMS or one-time password SMS is used for authentication. The OTP is usually a randomly generated number or an alphanumeric code that is entered into your website or app to verify portal logins, payment confirmations, or service requests for your business. This is part of a mandatory two-factor authentication process to protect your customers’ interactions with businesses.

Why use Exotel’s OTP SMS

Find out why you should use OTP SMS for Business Communication in this video

Why Exotel?

Industry-standard delivery & engagement rates

Our intelligent SMS routes ensure that your business messages get delivered every time, on-time, for instant communication.


TRAI & DLT scrubbing compliance

We’ve made it extremely easy to comply with TRAI guidelines and DLT template scrubbing with resources to help you every step of the way.

Unbeatable prices

We offer the best prices in the market. Show us lower rates and we will match them.

Real-time reports

Know performance levels of your OTP SMS campaigns through metrics like delivery, open and click rates.

Highly flexible

Working on the REST format, our OTP SMS APIs are programmable to work with your enterprise tech stack. 

Simple to implement & use

Our platform’s user-friendly and straightforward interface allows you to set up an SMS campaign in 5 minutes.

Best-in-class security protocols

Our platform is secured end-to-end through robust practices. That means your customer data is completely safe with us.

Unbeatable platform uptimes 

We guarantee best-in-class platform uptimes of 99.94% – this includes operator uptimes

How can businesses use SMS OTP?


To allow your customers secure access to websites like net banking or to allow delivery agents into secured communities, OTP SMS play a crucial role

Transaction Verification

Protect your customers from financial fraud by authenticating transactions of any value.


Safely allow your customers to gain access to portals they were kept out of due to unsuccessful password attempts or any email address or phone number changes.

Account reactivations

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

Shifting away from password logins

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

How does OTP SMS service work?



Verification request by the customer

Customer clicks on the ‘Verify’ button on your app or website and a unique OTP is generated in your backend system.


Exotel verification

Exotel fetches the generated OTP and sends it to your customer’s registered mobile number through an SMS.


Customer’s number is verified

Your customer enters the unique OTP (sent to him/her via an SMS) in your app or website and gets verified instantly.

Benefits of using OTP SMS


Assured, rapid, 24×7 delivery

With dedicated SMS routes for OTP SMS, messages are not interrupted by any peak in SMS traffic. And an SMS is usually delivered in a few seconds.



An OTP SMS service offers one of the highest cost-benefit ratios when it comes to a reliable, fast, and accurate authentication channel.


Prevent spam

Create a security filter with OTP verification to prevent fake web form or product sign-ups so you only the right requests reach the right teams.


Easy software integrations

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


Personalise formats

Popular vendors offer easy-to-configure OTP SMS APIs to set up any of the use cases listed here.


Track performance

Gauge deliverability and open rates by pulling reports from the dashboard. Test different strategies to improve results.

Asia’s most innovative companies use Exotel

Chirag Patel

Exotel's API documentation and implementation process is extremely simple and easy to follow. There were no hassles in setting it up. We use other cloud telephony platforms as well but Exotel gets a big thumbs-up from us for their ease of use.

Engineering Manager, 1mg

Shashank ND

We have worked across cloud telephony players and with other vendors, but the fact is Exotel is dependable.

Co-Founder & CEO, Practo

Prateek Jain

The number masking feature has been a very worthy addition to making our customer experience even better.

Former Associate Director - Driver Experience, Olacabs


Exotel's automated calls have helped in increasing our service levels and reducing our costs since there is no need for any manual intervention.

Senior Manager - Operations and Strategy

Praveen Kumar

Exotel's APIs are very clearly defined. Our tech team could integrate them in no time. It’s easy to incorporate into any product.

Assistant Vice President, Quikr Services

Satish Chugh

Very supportive and understanding staff who have lived up to every expectation, and at times exceeded them too.

Senior Manager- Last Mile Design, Ekart

How our customers use our SMS Solutions

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

Read More

How Exotel helped Practo revolutionise the way people connect with doctors

Read More

99dotco improved lead attribution by 20% by sending SMS alerts for missed customer calls

Read More


What are the inbound and outbound call charges?

Call charges for inbound and outbound calls are as follows:

For Indian customers
Pricing starts from**
Single-Leg Call Charges (Same Circle) - INR 0.40/min
Single-Leg Call Charges (Other Circle) -INR 0.75/min
**The prices vary based on volumes of calls. Talk to sales for more or sign up and test our free trial for 15 days

For International customers
Pricing varies on the country you want to make or receive calls from. Contact our international sales for pricing details.

Note: To get a correct price estimation based on your volumes and use case, please contact our sales team.


Contact Us

How fast can I set up my account?

Usually, account activation takes 30 minutes. Here are the steps to follow -

1. Sign up for a trial
2. Verify your number and the virtual number assigned to your account
3. Complete your KYC

Once your KYC is verified (usually takes 30-45 minutes), you can start making/receiving calls and sending SMSes from your dashboard. 


Know More

How to choose the best OTP service provider in India?

Choosing a reliable OTP service provider in India is the key to implement a robust authentication system. Below are some of the important factors to consider:

1. Delivery and Latency Rates: Always choose a provider that can assure you of better OTP delivery rates and lower latency rates.​

2. Flexible APIs: If you are implementing an OTP authentication system using APIs, then make sure that your OTP service provider’s APIs are flexible and easy to implement in your backend systems.

3. Data Security: Your customers’ data should be your number one priority. Always choose a provider that is ISO certified and exercises enterprise-grade security practices.

4. Scalability: Always choose a provider that can quickly scale up or down according to your business needs.

5. Customer Service: Choose an OTP service provider that values your time and truly cares about your success. Always ask if you are getting timely support in case you run into problems.

How much does SMS gateway cost?

The charges for SMS gateway is based on your usage. Contact our sales team to know more.


Contact Sales

How to send bulk SMS?

First, integrate the Exotel SMS Gateway with your application stack, following a simple process. Then, SMSes sent right from your website, CRM, ERP, mobile application etc., will then automatically pushed to your customers through the gateway.

How to add SMS gateway to my app?

The SMS Gateway is an HTTP based REST API which allows you to trigger SMSes using actions/buttons at your internal application. By simply integrating a small piece of code within your internal application, you can establish the connection between Exotel’s SMS Gateway and your apps.

How does bulk SMS gateway work?

As the user, you will send/schedule messages from within the applications you already use, for instance, a CRM. Behind the scenes, the SMS Gateway will translate the message into a compatible format that can be delivered to the recipient, and send it accordingly.


Learn More

How to build an SMS gateway server?

To build an SMS gateway server, you need to do the following:

1. Choose an SMS gateway application that can encode the SMS data

2. Set up a database that can store the data

3. Subscribe to a web server that will function as the transmission line between your SMS content

4. Check the SMS gateway functionality by sending messages to trial phone numbers


Set up a call



How to add SMS gateway to my website?

The process is the same as integrating it to the app. For questions on integration, please contact our sales teams.


What is the UL VNO License and in which circle we have the license?

UL VNO is a Unified License Virtual Network Operator. UL VNO license enables us to offer full fledged telecom services by the network of NSO (Network Service Operator) like Airtel, Tata etc.

We now have an UL VNO license in the Karnataka circle under entity name Veeno Communications Private Limited.


Try Exotel’s OTP SMS Solution Free for 7 days



Exhaustive guide on 2 factor authentication

From SMS OTP, to OTP over call, to email OTP, to no OTP at all! We show how 2FA evolved over time.

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.