Google reCaptcha V3 with PHP Prevent Spam Secure Web Forms

Using Google reCaptcha V3 with PHP is an effective way to block bots and secure your website’s forms. This guide shows you how to integrate it step-by-step for seamless protection.

Step 1: Obtain Your API Keys

Before implementing reCaptcha V3 with PHP, you need API keys. These keys allow your website to communicate with Google’s reCaptcha system securely. Follow these steps to get started.

Log in to your Google account and visit the Google reCaptcha website. Click “Admin Console” to register your site and get your API keys. Keep these keys secure.

The site key integrates reCaptcha into your forms, while the secret key ensures secure server-side validation. Keep the secret key private.

Step 2: Integrate reCaptcha with PHP

To integrate reCaptcha into your website, include the API script in your HTML file, create a protected form, and validate the responses on the server. Here’s how:

First, add the reCaptcha API script to the `` of your HTML. Replace “YOUR_RECAPTCHA_V3_SITE_KEY” with your site key:

Next, create a form with a hidden field for the reCaptcha token. Use the following example:

        

            
            Submit
        
    

Finally, validate the response token on your server using the following PHP code:

        if (isset($_POST['g-recaptcha-response'])) {
            $secret = 'YOUR_RECAPTCHA_V3_SECRET_KEY';
            $response = $_POST['g-recaptcha-response'];
            $verify = file_get_contents("https://www.google.com/recaptcha/api/siteverify?secret={$secret}&response={$response}");
            $responseData = json_decode($verify);
            if (!$responseData->success || $responseData->score < 0.5) {
                die('reCaptcha verification failed.');
            }
        }
    

Step 3: Test Your Integration

Testing ensures your reCaptcha V3 integration works as intended. First, submit the form to verify it processes valid tokens correctly. Then, simulate bot activity and confirm reCaptcha blocks those requests.

Check your Google reCaptcha logs regularly to identify any unusual activity and troubleshoot errors promptly.

Step 4: Optimize reCaptcha Settings

Adjust reCaptcha settings in the Google Admin Console to balance security and user convenience. Lowering the score threshold makes it stricter but may affect real users. Review analytics regularly to improve effectiveness.

Optimized settings ensure that your website remains secure without compromising the user experience.

Conclusion

By integrating reCaptcha V3 with PHP, you can prevent spam and protect your web forms from bots. Follow this guide to set up and test the integration for a secure, reliable solution. Regular updates and monitoring will ensure ongoing success.