reCAPTCHA is a free service provided by Google that helps protect websites from spam and automated abuse. It is a form of CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart), which is a test designed to determine whether the user is a human being or a computer. reCAPTCHA does this by presenting tasks that are easy for humans but difficult for computers, such as recognizing distorted text, images of objects, or sounds.
The reCAPTCHA service is widely used on the Internet to:
- Protect registration and login forms from bot attacks.
- Safeguard comment and feedback systems from automated spam messages.
- Ensure that only human users can access certain online resources or services.
Over time, reCAPTCHA has evolved to become more user-friendly and less intrusive, with versions such as reCAPTCHA v2 introducing the famous "I am not a robot" checkbox, and reCAPTCHA v3 working in the background to assess user behavior without interrupting the user experience.