Google reCAPTCHA v1, v2 and v3 explained

Google reCAPTCHA has evolved over time to provide more effective and user-friendly solutions for preventing automated abuse and spam. Here’s a comparison of reCAPTCHA v1, v2, and v3:

reCAPTCHA v1

Status: Deprecated and no longer supported by Google.

Features:

• Text-based CAPTCHA: Users had to type the text they saw in an image.
• Accessibility: Audio CAPTCHAs were available for visually impaired users.
• User Experience: Often frustrating for users due to difficulty in reading the text, leading to high bounce rates.

Disadvantages:

• High Friction: Required active user interaction.
• User Frustration: Could be difficult to solve, leading to poor user experience.
• Security: Vulnerable to advancements in OCR technology.

reCAPTCHA v2

Status: Actively supported.

Features:

• “I’m not a robot” Checkbox: Users simply click a checkbox to confirm they are not a robot.
• Invisible reCAPTCHA: Automatically triggers verification based on user behavior without requiring user interaction unless suspicious activity is detected.
• Image Recognition: Users may be prompted to identify images (e.g., “Select all images with traffic lights”) if further verification is needed.
• Accessibility: Improved accessibility features compared to v1.

Advantages:

• Better User Experience: Less intrusive, with simple checkbox or image selection.
• Improved Security: More advanced algorithms to detect bots.
• Flexibility: Options for both visible and invisible challenges.

Disadvantages:

• Interaction Required: Some users may still need to interact with the CAPTCHA, which can be a minor inconvenience.

reCAPTCHA v3

Status: Actively supported.

Features:

• No User Interaction Required: Continuously monitors user behavior to assign a risk score, determining whether the user is a bot or human without interrupting the user.
• Score-Based: Provides a score (0.0 to 1.0) indicating the likelihood of a user being a bot (0.0 being very likely a bot and 1.0 being very likely a human).
• Action Tags: Allows site owners to implement different actions based on the score (e.g., blocking actions, requiring additional verification, etc.).
• Integration: Can be integrated with existing forms and actions seamlessly.

Advantages:

• Seamless User Experience: No interruptions for users, as there are no visible challenges.
• Continuous Monitoring: Uses advanced machine learning to monitor user behavior over time, making it more difficult for bots to mimic human behavior.
• Flexibility and Control: Site owners can decide how to handle users based on the risk score.

Disadvantages:

• Implementation Complexity: Requires more setup and understanding of how to handle different risk scores.
• Privacy Concerns: Continuous monitoring may raise privacy issues for some users and site owners.

Summary and Recommendations

• reCAPTCHA v1: Deprecated and should not be used.
• reCAPTCHA v2: A good balance between security and user experience, suitable for most applications needing user interaction to verify human presence.
• reCAPTCHA v3: Provides the best user experience with no interruptions, suitable for applications needing continuous risk assessment and wanting to avoid any user interaction for CAPTCHA challenges.

When to Use Each Version

• reCAPTCHA v2: Use this when you need a straightforward, moderately intrusive CAPTCHA solution that balances security and user experience.
• reCAPTCHA v3: Use this for a seamless user experience where you can handle risk scores effectively and want to avoid any CAPTCHA interaction.

Implementation Tips

• reCAPTCHA v2:

  <script src="https://www.google.com/recaptcha/api.js" async defer></script>
  <form action="?" method="POST">
    <div class="g-recaptcha" data-sitekey="your_site_key"></div>
    <br/>
    <input type="submit" value="Submit">
  </form>
  

• reCAPTCHA v3:

  <script src="https://www.google.com/recaptcha/api.js?render=your_site_key"></script>
  <script>
    grecaptcha.ready(function() {
      grecaptcha.execute('your_site_key', {action: 'homepage'}).then(function(token) {
        // Add your logic to submit to your backend server here.
      });
    });
  </script>