Top 10 OTP Service Providers in 2024

In today’s internet enabled world, security is a paramount concern for the apps and web applications that use the personal data, medical data, and other data, the leaks of which can seriously harm an individual who is using your app. There have been many episodes of data theft worldwide in the past which evidently makes security the top priority while developing the mobile and web applications.

Various methods are in place to ensure that the data is viewed, edited, and submitted by the rightful owner. One such method is OTP i.e. One Time Password.

What are OTPs?

One Time Passwords or OTPs are a mechanism implemented to add an extra layer of security to ensure the security of the sensitive data and as an access control mechanism. It ensures that the person in rightful possession or only the owner can access the required app or the data.

How does the OTP mechanism work?

1.?User Request Initiation:

When the user attempts to authenticate or perform an action requiring additional security, the server generates an OTP request.

2.?OTP Generation:

The OTP can be generated using a few standard algorithms like:

a.?HOTP (HMAC-based One-Time Password): Based on a counter. The OTP changes after every request, regardless of time.

b.?TOTP (Time-based One-Time Password): Based on the current time, often synchronized with the server, and changes periodically (usually every 30 seconds).

●?Generation Process:

○?The server generates the OTP by running an algorithm that takes a shared secret key and a counter (for HOTP) or timestamp (for TOTP).

○?The generated OTP is a short numeric or alphanumeric string (usually 6-8 characters).

○?Example: Using TOTP, if the current timestamp is hashed with a secret key, the OTP for 14:30 might be 839271.

3.??OTP Delivery:

The generated OTP is delivered to the user via one of these methods:

a.?SMS: Sent to the user's registered mobile number.

b.?Email: Sent to the user's registered email.

c.??Authenticator App: The user can generate the OTP on apps like Google Authenticator, using a shared secret set up during the initial configuration.

4.??User Input:

The user receives the OTP and inputs it into the application or website.

5.??Server Verification:

a.?The server receives the OTP input from the user.

b. It checks the OTP against the expected value (calculated using the same algorithm).

c.?The OTP is validated based on factors like:

■?Time window: For TOTP, the server checks if the OTP is still valid within the current time frame (usually 30 seconds).

■?Replay attack protection: Ensures the same OTP isn’t used again, even if still valid.

6.?Response:

If the OTP matches the expected value and is within the validity period, the server authenticates the user. If not, the process fails, and the user is prompted to retry or request a new OTP.

Who are OTP service providers?

OTP service providers are the third-party companies who provide the OTP authentication process explained above without you having to implement it in a bespoke manner everytime you develop an application.

Top 10 OTP service providers

1.?Twilio Verify: Twilio's Verify service allows businesses to send one-time passcodes (OTPs) to users, enhancing security during logins, sign-ups, and other actions. OTPs can be delivered via SMS, voice calls, email, or WhatsApp. Users enter these codes to verify their identity, preventing unauthorized access and protecting sensitive customer data from third parties.

2.?Firebase Authentication: Firebase Authentication by Google provides a seamless solution for phone number-based OTP logins. Users input their phone number, and Firebase sends a unique SMS code. Upon entering this code in the app, users verify their identity, enhancing security beyond passwords. Firebase manages code generation, sending, and verification, simplifying integration for developers.

3.?MSG91: MSG91 is an Indian cloud communication platform that specializes in mobile solutions for businesses. It offers features such as SMS marketing, OTP verification for two-factor authentication, and voice calls. With an emphasis on reliability and scalability, MSG91 enhances customer engagement and streamlines communication through effective mobile channels for the Indian market.

4.?SMSCountry: SMSCountry is a global bulk SMS messaging platform designed for businesses. It offers an easy-to-use interface for sending promotional SMS blasts, transactional alerts like order confirmations, and one-time passcodes (OTPs) for secure logins. With reliable delivery, competitive pricing, and extensive reach, SMSCountry is ideal for businesses aiming to connect with customers worldwide.

5. 2Factor.in: 2Factor.in is an Indian company that offers SMS APIs to facilitate two-factor authentication (2FA) via phone verification. Businesses can integrate their platform to send one-time passcodes (OTPs) during logins or other security-sensitive actions. With fast OTP delivery, 24/7 support, a pay-per-delivery model, and data privacy protection, they provide a cost-effective 2FA solution for Indian businesses.

6.?Exotel: Exotel is a leading cloud-based communication platform in India, catering to businesses of all sizes worldwide. It provides SMS APIs for sending transactional alerts, marketing messages, and one-time passcodes (OTPs) for secure logins. With a focus on scalability and security, Exotel simplifies communication management, enhancing customer engagement and streamlining operations.

7.?SendInBlue (Brevo): SendInBlue, now known as Brevo, offers a transactional SMS API that developers can use to integrate OTP functionality into their applications. This API enables the programmatic sending of SMS messages, including OTP codes, for user verification during logins or secure actions. While not solely for OTPs, Brevo's API allows developers to create tailored OTP experiences in their applications.

8.?Fast2SMS: Fast2SMS is an Indian company providing bulk SMS services with a particular emphasis on one-time passwords (OTPs) for two-factor authentication (2FA). They offer OTP SMS APIs for businesses to send secure OTP codes directly to users’ phones during logins and transactions. Fast2SMS ensures reliable and fast OTP delivery through dedicated routes, essential for secure user verification.

9.?TeleSign: TeleSign offers a specialized SMS Verify API for secure one-time password (OTP) delivery in two-factor authentication (2FA). Emphasizing robust security, it allows sending OTPs via SMS, voice calls, or WhatsApp, providing flexibility for users. This focus on security makes TeleSign an excellent choice for businesses seeking a reliable OTP solution for 2FA.

10.?Okta Verify: Okta Verify is a mobile app for two-factor authentication (2FA) provided by Okta. It enhances security by allowing users to approve logins with a tap on their phone instead of waiting for SMS codes. Even offline, it can generate one-time codes, and it supports fingerprint or face ID for added security, eliminating the need to remember codes.

Each of the above mentioned OTP service providers has its own pros and cons. However, at the moment, these are the top 10 OTP service providers in the software industry. Secure your app today with multi-factor authentication using OTP service providers and contacting a top mobile app development company .