CAPTCHA

CAPTCHA or Completely Automated Public Turing Test to tell Computers and Humans Apart, tests are used by websites to distinguish between humans and robots when conducting specific actions on it.

Updated: November 3, 2023

CAPTCHA or Completely Automated Public Turing Test to tell Computers and Humans Apart, tests are used by websites to distinguish between humans and robots when conducting specific actions on it.

Bot detection and mitigation software is used by organizations to protect themselves from unauthorized users and defend against attacks. Bots are prevented from completing their intended activities by using these tools.

Users are asked to complete a challenge involving random characters or images when CAPTCHA is used. Characters are twisted and warped by a traditional text-based CAPTCHA to prevent bots from understanding and deciphering them. Users have to interpret the warped characters, input them in the order they are shown into a form, and then submit the form to pass the test, and proceed to the following action.

Text-based and image-based CAPTCHA tests are the most commonly used CAPTCHA validation. Text-based CAPTCHA, Image-based CAPTCHA, Audio CAPTCHA, No CAPTCHA, Math CAPTCHA and reCAPTCHA by Google are some other types of CAPTCHA validation used by websites.

CAPTCHAs are generally used for avoiding spam and preventing bots from proceeding with requests. Ensuring integrity in polls, reducing registrations of fake accounts and preventing false comments and misinformation are some additional benefits of CAPTCHA.

Negative user experience, inaccessibility to certain users and overall imperfection are some challenges of CAPTCHA.

Types of CAPTCHA


  • Text-Based CAPTCHA: Users must enter characters or numbers displayed in an image.
  • Image-Based CAPTCHA: Users identify objects, patterns, or elements within images.
  • Audio CAPTCHA: Users listen to and transcribe spoken words or numbers.
  • Math CAPTCHA: Users solve mathematical equations or puzzles.
  • Honeypot CAPTCHA: Involves hidden form fields that should remain empty.
  • Checkbox CAPTCHA: Requires users to check a box to confirm their humanity.
  • ReCAPTCHA: An advanced CAPTCHA by Google that combines text and image recognition.
  • 3D CAPTCHA: Involves identifying objects or text within three-dimensional images.
  • NoCAPTCHA reCAPTCHA: Requires users to click a checkbox to prove they are not bots.
  • Social Media CAPTCHA: Users authenticate through their social media accounts.
  • Game-Based CAPTCHA: Users play a short game or solve a puzzle.
  • Pattern Recognition CAPTCHA: Users recognize and replicate specific patterns.