{"id":31690,"date":"2021-06-01T06:08:44","date_gmt":"2021-06-01T06:08:44","guid":{"rendered":"\/tutorials\/?p=31690"},"modified":"2026-03-09T19:19:16","modified_gmt":"2026-03-09T19:19:16","slug":"what-is-recaptcha","status":"publish","type":"post","link":"\/ng\/tutorials\/what-is-recaptcha","title":{"rendered":"What is reCAPTCHA? everything you need to know"},"content":{"rendered":"

reCAPTCHA <\/strong>is a free Google service that protects websites from spam and abuse by distinguishing human users from automated bots. Using machine learning and advanced risk analysis, it is a more advanced version of the traditional CAPTCHA<\/strong> system.<\/p>

The Turing test is a method to determine whether or not computers can exhibit human-like behavior. This kind of behavior is examined by reCAPTCHA and is often employed to prevent abuse of sign-up, contact forms, or comment sections.<\/p>

There are multiple types of CAPTCHA tests available, from using a real-life image or a simple checkbox. This article will share how the different types of tests work and how to install this kind of test on your site.<\/p>

Download glossary for web beginners<\/a><\/p>

\n\n\n\n\n<\/p>

How Does reCAPTCHA Work<\/h2>

The reCAPTCHA verification process uses artificial intelligence (AI) to recognize human behavior that the bots can’t follow. The tests need to be passable by any human user, regardless of age, gender, education, or language.<\/p>

CAPTCHAs are all automated so that the computer program can grade the test without the interference of humans. Due to this reason, the tests are constantly evolving as both the CAPTCHA AI and malicious bots become more advanced.<\/p>

The verification process of traditional CAPTCHAs works by forcing users to solve tests before allowing access. The CAPTCHA tests use random letters and numbers, warping them in a way that is hard for automated programs to translate. Previously, this has been a sufficient deterrence method, as bots would have difficulty recognizing these distorted letters or numbers.<\/p>

However, more advanced bots have been developed, with the ability to quickly solve traditional CAPTCHAs<\/a> with algorithms trained in pattern recognition. The traditional CAPTCHAs then were replaced with more complex tests in the form of reCAPTCHA v1<\/strong>.<\/p>

These reCAPTCHA tests used a computer-generated word and distorted text via images from old books or news articles. However, this version is no longer available as it was found to be too easy for the bots and too hard for human users.<\/p>

reCAPTCHA v2<\/strong> followed afterward, hoping to provide more complex tests to deter bots while remaining solvable by humans. This updated reCAPTCHA test requires users to select images matching a theme or check a box next to the text, stating “I’m not a robot”<\/strong>.<\/p>

An even newer version – reCAPTCHA v3<\/strong> – aims to avoid disrupting the user experience. This version limits user interaction by calculating a score according to the present user behavior and history. Computers then determine the score for the user in a preliminary Turing test.<\/p>

The website owner has three possible responses based on the score – to grant access, block the user, or deploy reCAPTCHA v2 tests. The two available tests for this method are the image reCAPTCHA and checkbox reCAPTCHA.<\/p>

Image reCAPTCHA<\/h3>

The image recognition reCAPTCHA test uses either nine or 16 lower resolution real-life images in the form of a square. Above these images, users will find displayed instructions on which image sections should be selected. For example, the instruction might ask users to select all squares featuring crosswalks or fire hydrants.<\/p>

Once the user has selected the squares, the computer program will compare the response with other responses. If the user’s response matches that of most other users, they pass the test.<\/p>

The test presents images that humans see every day and can easily recognize. Whereas even advanced bots will have a hard time selecting objects from low-resolution images.<\/p>

This test is also available in an audio version, which makes it accessible to visually impaired users. The audio test will vocalize random letters and numbers using distorted audio, prompting users to answer using text input.<\/p>

\"Image<\/a><\/figure><\/div>

Checkbox reCAPTCHA<\/h3>

Users don’t need to solve or recognize anything to pass the checkbox reCAPTCHA test. Simply check a box next to the statement saying “I’m not a robot”<\/strong>.<\/p>

This test distinguishes humans from bots by following the cursor movement as it approaches the checkbox. Even a human user with the most stable hand will display some randomness in cursor movement, even on a microscopic level. A bot, typically, will not be able to mimic this kind of movement, preferring to act in a straight line.<\/p>

If the cursor movement indicates that the user is a human, a green check icon will be displayed upon clicking the box.<\/p>

Other than following the cursor movement, this test also assesses HTTP cookies and history present in the web browser.<\/p>

\"Checkbox<\/a><\/figure><\/div>

Pros and Cons of reCAPTCHA<\/h2>

reCAPTCHA helps to prevent bots from spamming website pages. It will always be beneficial to install this test to protect your site if you have open registration and comment sections.<\/p>

However, the system does feature certain disadvantages as well. Here are some of the pros and cons of using reCAPTCHA on your site.<\/p>

Pros<\/h3>

reCAPTCHA actively protects the integrity of your site by preventing spam, abuse, and data theft from bots.<\/p>

Here are some of the most significant pros of using reCAPTCHA:<\/p>