CAPTCHA
CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) is a security tool used to distinguish human users from automated bots on websites and applications. It typically presents challenges that are easy for humans to solve but difficult for computers, such as distorted text recognition, image selection, or puzzle-solving tasks. Its primary purpose is to prevent spam, abuse, and unauthorized access by automated scripts.
Developers should implement CAPTCHA when building systems that require user authentication, form submissions, or public-facing interfaces to mitigate automated attacks like brute-force login attempts, comment spam, or data scraping. It is particularly useful for protecting sensitive operations like account creation, password resets, and payment transactions, where bot interference could lead to security breaches or degraded user experience. However, it should be balanced with accessibility and user-friendliness, as overly complex CAPTCHAs can frustrate legitimate users.