OTP API (One-Time Password Application Programming Interface) is a service that allows developers to integrate OTP functionality into their applications, websites or systems. OTP is a password that is valid for only one login session or transaction, which enhances security by reducing the risk of password theft, hacking, or identity theft. OTP can be delivered to the user through various channels, such as SMS, email, or push notifications, and can be generated using this api, as time-based code.