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What is CAPTCHA? How Does CAPTCHA Work on a Website?

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When opening a website, we are often asked to verify ourselves through a CAPTCHA with several options, starting from using a series of numbers, alphabets, or even pictures that we need to fill in based on the instructions provided. Apart from that, what is CAPTCHA?

CAPTCHA is an abbreviation for Completely Automated Public Turing test to tell Computers and Humans Apart. CAPTCHA is the of a website security system that utilizes a bot. For more detail, read the explanation below!

What is CAPTCHA? and How Does It Work on a Website? 

CAPTCHA is an assessment aimed to distinguish between humans and robots. By using CAPTCHA, any website will be able to monitor whether the visitors are real humans or not.  

CAPTCHA is mostly available in various kinds such as identifying pictures or rewriting the numbers or alphabets based on the instructions provided. This is an easy task to do and can be done by humans but not by robots or computer systems. Therefore, this is the main reason why CAPTCHA should be implemented on a website.


How does CAPTCHA work? When you caught sight of a pop-up window while surfing on the Internet, you need to fill in or pick things based on the instructions. After that, you can continue to enjoy the website you intend to visit. By doing this test, the site you visit will understand that you are a real human, not a robot.

The Function of CAPTCHA for a Website

Not only to verify, but CAPTCHA also has a few other functions as follows:

  1. CAPTCHA will automatically block bots on a website. 
  2. Automatically prevent spam in a form of a message or commentary.
  3. An efficient course of action to protect websites from viruses in the online world. 
  4. Beneficial to avoid spamming caused by a bot on a registration system, usually a bot will develop a fake account.
  5. Reduce and prevent fake comments that are automatically made by a bot.

The Types of CAPTCHAs

There are several kinds of CAPTCHA available, and you have probably encountered at least one of them. The following are the 3 kinds of CAPTCHA tests that mostly will be found on websites:

  1. Pictures: There are checkered pictures, and you need to pick one based on the instructions. For example, if you are asked to click a picture of a ship, you need to pick from the available pictures on your screen that contain a ship in it. 
  2. Numerical: You need to retype the series of the number shown on your screen,  
  3. Alphabetical: Similar to the numerical test, you have to retype the alphabet in the available box. 

There you have it! Now you understand what CAPTCHA and its functions for a website are

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