Glossary term
What is OTP / TOTP (One-Time Password / Time-based OTP)?
OTP / TOTP stands for One-Time Password / Time-based OTP.
A short-lived code. Example: 6-digit SMS code; authenticator app code that changes every 30 s.
Learn it properly · System DesignLesson 49: Authentication vs Authorization: Sessions, Cookies & JWTEvery endpoint checked “is the user logged in?” — and changing one number in the URL showed another customer's invoice. Authentication vs authorization, storing passwords, MFA and passkeys, sessions vs JWTs (with a live token to tamper with), and RBAC, ABAC and ReBAC.