HomeSMSOTP / One-Time Password

SMS OTP — One-Time Password Service

Secure your web applications, banking portals, and e-commerce platforms with SMS One-Time Password (OTP) verification. Fast, reliable, and easy to integrate via iSMS API.

Get OTP API Access →
SMS OTP Flow Diagram
What is SMS OTP?

One-Time Password (OTP) Explained

One-Time Password (OTP) is a single-use password sent to the user's registered mobile number for secure account access. It is also known as two-factor authentication (2FA). Internet banking portals use OTP to verify user transactions — protecting against password sniffing, replay attacks, and identity theft.

OTP uses two main techniques to generate passwords:

  • Time-Synchronisation: The password is only valid for a short period of time (e.g. 60 or 300 seconds).
  • Mathematical Algorithm: A new, random password is generated using secure algorithms each time it is requested.
How It Works

SMS OTP Process — Step by Step

OTP codes are sent to the registered mobile number only. iSMS service is protected by strong security protocols.

1

User Requests OTP

User clicks "Get OTP" on your website or app.

2

Backend Verification

Request sent to your backend server for validation.

3

iSMS API Call

Your server calls iSMS API with the OTP message and mobile number.

4

User Receives OTP

User receives the OTP code via SMS on their phone.

5

Access Granted

User enters the code — once verified, access is granted.

Integrate SMS OTP into Your Application

Register free and use iSMS API to send OTP codes in seconds. Supports PHP, Java, C#, Python, and more.

Register Free Account → View SMS API Docs

📞 1800 87 7061  ·  +603 2780 3880  ·  [email protected]

📱 SMS Coverage — All Countries Worldwide

A B C D E F G H I J K L M N O P Q R S T U V Y Z