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Which is Better SMS-OTP, Missed Call OTP, or WhatsApp OTP?

Explore the different options for one-time password (OTP) and learn which is better for your authentication needs. Discover the pros and cons of SMS-OTP, missed call OTP, and WhatsApp OTP here!
by fazpass
June 16, 2023
which otp is better?

A one-time password (OTP) is a common authentication method that can be used to secure access to various accounts and online services. There are several different ways to send one time passwords, including via SMS messages, missed calls, and WhatsApp messages.

Each method has its own pros and cons, and it is important to take this into account when deciding which method to use. A one-time password (OTP) is a common security feature used to protect against unauthorized access to an account or system. They are often used in combination with usernames and passwords to provide an extra layer of security

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What is SMS OTP?

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In the application of SMS OTP (one-time password), users are sent a one-time code via text message (SMS) to their mobile phone. The user then enters this code into the website or app to complete the login or verification process. OTP SMS is relatively secure, as it is sent over a secure network and cannot be accessed by anyone who does not have access to the user's mobile phone. This helps ensure that only the phone owner can access the account, as the OTP is sent to a device that only the user can access.

The usage of OTP SMS is common in banking, online shopping, and other sensitive transactions. They are generally considered a secure method of verifying a user's identity, but certain types of attacks can exploit their vulnerability. Like SIM swapping, where an attacker gains access to the victim's phone number and can intercept one time passwords sent to that number.

To defend against SIM swap attacks, it's crucial to employ robust passwords and activate supplementary security measures. One such measure is two-factor authentication (2FA), which necessitates the utilization of a secondary device or authentication method alongside one time password.


  1. OTP SMS is convenient for users because most people have a mobile phone and can receive SMS messages.
  2. Implementing one time password SMS is quick and easy since it can be sent and received using standard phone hardware and software.
  3. one time password SMS is considered relatively secure since it is transmitted over a secure network and remains inaccessible to anyone without access to the user's mobile phone.


  1. OTP SMS can be vulnerable to SIM swap attacks, where an attacker gains control of the user's mobile phone number and intercepts OTP intended for the user.
  2. OTP one time password provides reliability in areas with poor cellular coverage or when the user's phone is turned off or out of range.
  3. Some users may not want to receive SMS messages due to privacy or other reasons and may prefer alternative methods of sending one time password.

What is Missed Call OTP?

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By implementing a missed call OTP (one-time password), the system sends the OTP to the user's phone number through a missed call. Users can then retrieve the OTP by checking for missed calls on their phones and jotting down the displayed number.

This OTP can then be entered into the corresponding field on the website or application to complete the authentication process. It is important to note that one-time passwords are usually only valid for a short period of time. So, it is important to use the OTP as soon as possible after receiving it. If the one-time password expires before use, the user usually needs to request a new one-time password.

Pro Missed Call OTP

  1. OTP missed calls are convenient for users because they do not require users to have a smartphone or internet connection.
  2. Implementing Missed call one time password is quick and easy since it can deliver using standard phone hardware and software.
  3. It's easy for the user to understand Android even has an autofill feature

Cons Missed Call OTP

  1. One time password missed calls are vulnerable to phone number spoofing attacks, where an attacker can make a call apparently coming from a different number than the one actually made.
  2. Missed call OTPs may not be suitable for use in cases where the user cannot receive phone calls. For example, when users are in a meeting or on a plane.

What is WhatsApp OTP?

WhatsApp OTP (one time password) is a security feature of WhatsApp that verifies user identity during registration or login. It sends a unique one time password to your registered phone number when signing up or logging in to a new device. You need to enter this OTP within a limited time to verify your identity and gain access to the account.

Pro WhatsApp OTP

  1. Enhanced security with two-factor authentication.
  2. Simplified verification process.
  3. Real-time verification for added security.

Cons WhatsApp OTP

  1. Dependency on phone number, which can be problematic if you change or lose access to it.
  2. Vulnerability to SIM swap attacks.
  3. Reliance on an internet connection for one time password delivery.
  4. Potential issues with SMS delivery, causing delays or non-receipt of the code.

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