What is OTP SMS? How One-Time Passwords Work in Nepal

OTP SMS stands for One-Time Password sent via text message. It is a widely used method to verify user identity during login, registration, password reset or financial transactions.

How OTP SMS works

1. User enters their phone number
2. Your server generates a random code
3. The code is sent via SMS to the user's phone
4. User enters the code into your app
5. Your server validates the code and grants access

Why OTP SMS is important

Passwords can be stolen or guessed. OTP adds a second factor: something the user has (their phone). Even if a password is compromised, an attacker cannot log in without the OTP.

OTP best practices

• Keep OTPs short, usually 4–6 digits
• Set a short expiry time, typically 5 minutes
• Limit retry attempts to prevent brute force
• Use a dedicated high-priority route for speed
• Provide voice OTP fallback for delivery failures