How to Set Up CAPTCHAs on Your Website

Setting up CAPTCHAs on your website is a straightforward process that can help protect your forms from spam and bots. Below is a step-by-step guide to implementing CAPTCHAs using Google reCAPTCHA, one of the most popular and effective CAPTCHA solutions.

Step 1: Sign Up for Google reCAPTCHA

1. Go to the Google reCAPTCHA website.
2. Sign in with your Google account.
3. Click Create to set up a new reCAPTCHA.

Step 2: Configure reCAPTCHA

1. Label: Give your reCAPTCHA a name (e.g., “Contact Form CAPTCHA”).
2. Choose reCAPTCHA Type:
   • reCAPTCHA v3: Works in the background and assigns a score to user interactions (recommended for most websites).
   • reCAPTCHA v2: Requires users to check a box or solve a challenge (e.g., “I’m not a robot”).
3. Domains: Add your website’s domain (e.g., yourwebsite.com).
4. Accept the Terms of Service and click Submit.

Step 3: Get Your reCAPTCHA Keys

After creating the reCAPTCHA, Google will provide two keys:

• Site Key: Used in your website’s frontend code.
• Secret Key: Used in your backend code for verification.

Step 4: Add reCAPTCHA to Your Website

For reCAPTCHA v2 (Checkbox or Challenge)

1. Add the reCAPTCHA script to your HTML:
   html

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   <script src="https://www.google.com/recaptcha/api.js" async defer></script>

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2. Insert the reCAPTCHA widget in your form:
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   <form action="submit-form.php" method="POST">
     <!-- Your form fields here -->
     <div class="g-recaptcha" data-sitekey="YOUR_SITE_KEY"></div>
     <br/>
     <input type="submit" value="Submit">
   </form>

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For reCAPTCHA v3 (Background Verification)

1. Add the reCAPTCHA script to your HTML:
   html

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   <script src="https://www.google.com/recaptcha/api.js?render=YOUR_SITE_KEY"></script>

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2. Add a hidden input field to your form:
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   <form action="submit-form.php" method="POST" id="myForm">
     <!-- Your form fields here -->
     <input type="hidden" name="recaptcha_response" id="recaptchaResponse">
     <input type="submit" value="Submit">
   </form>

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3. Add JavaScript to generate a token:
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   <script>
     document.getElementById('myForm').addEventListener('submit', function(event) {
       event.preventDefault();
       grecaptcha.ready(function() {
         grecaptcha.execute('YOUR_SITE_KEY', {action: 'submit'}).then(function(token) {
           document.getElementById('recaptchaResponse').value = token;
           document.getElementById('myForm').submit();
         });
       });
     });
   </script>

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Step 5: Verify reCAPTCHA on the Server Side

1. In your backend (e.g., PHP, Node.js, Python), verify the reCAPTCHA response:
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   <?php
   if ($_SERVER['REQUEST_METHOD'] === 'POST') {
       $recaptchaResponse = $_POST['recaptcha_response'];
       $secretKey = 'YOUR_SECRET_KEY';
       $url = "https://www.google.com/recaptcha/api/siteverify?secret=$secretKey&response=$recaptchaResponse";
       $response = file_get_contents($url);
       $responseKeys = json_decode($response, true);
   
       if ($responseKeys['success']) {
           // reCAPTCHA verification passed
           // Process the form submission
       } else {
           // reCAPTCHA verification failed
           echo "CAPTCHA verification failed. Please try again.";
       }
   }
   ?>

Step 6: Test Your CAPTCHA

• Submit your form to ensure the CAPTCHA works correctly.
• For reCAPTCHA v3, check the score in the Google reCAPTCHA admin console to fine-tune your thresholds.

Tips for Using CAPTCHAs Effectively

1. Use reCAPTCHA v3 for Less Intrusive Protection:
   • It works in the background and doesn’t interrupt users.
2. Limit CAPTCHA Frequency:
   • Only show CAPTCHAs for suspicious activity.
3. Combine with Other Anti-Spam Measures:
   • Use honeypot fields, email validation, and IP blocking for added security.
4. Monitor Performance:
   • Regularly check your reCAPTCHA dashboard for insights into bot activity.