What Is OTP SMS Service? A Complete Guide to Secure & Instant Authentication (2025)

May 30, 2025 · 3 min read · What Does OTP SMS Service Mean? An OTP (One-Time Password) SMS service is a security feature that sends a unique, time-sensitive password to a user's mobile number. This password is valid for a short time—usually 30 seconds to 5 minutes—and is used f...