Google Recaptcha v3 example demo

Question

Until now, I was working with Google Recaptcha v2, but now I want to update my WebApp using the lastest version (v3).

Is it possible to anyone add a fully working Google Recaptcha v3 example for a basic form as I can't find any working demos of it?

I'd really appreciate it.

Thank you very much.

PS: I'm using Java Servlets on the server side, but it doesn't matter if you explain using PHP or whatever.

Answer 1

Simple code to implement ReCaptcha v3

The basic JS code

<script src="https://www.google.com/recaptcha/api.js?render=your reCAPTCHA site key here"></script> <script>     grecaptcha.ready(function() {     // do request for recaptcha token     // response is promise with passed token         grecaptcha.execute('your reCAPTCHA site key here', {action:'validate_captcha'})                   .then(function(token) {             // add token value to form             document.getElementById('g-recaptcha-response').value = token;         });     }); </script> 

The basic HTML code

<form id="form_id" method="post" action="your_action.php">     <input type="hidden" id="g-recaptcha-response" name="g-recaptcha-response">     <input type="hidden" name="action" value="validate_captcha">     .... your fields </form> 

The basic PHP code

if (isset($_POST['g-recaptcha-response'])) {     $captcha = $_POST['g-recaptcha-response']; } else {     $captcha = false; }  if (!$captcha) {     //Do something with error } else {     $secret   = 'Your secret key here';     $response = file_get_contents(         "https://www.google.com/recaptcha/api/siteverify?secret=" . $secret . "&response=" . $captcha . "&remoteip=" . $_SERVER['REMOTE_ADDR']     );     // use json_decode to extract json response     $response = json_decode($response);      if ($response->success === false) {         //Do something with error     } }  //... The Captcha is valid you can continue with the rest of your code //... Add code to filter access using $response . score if ($response->success==true && $response->score <= 0.5) {     //Do something to denied access } 

You have to filter access using the value of $response.score. It can takes values from 0.0 to 1.0, where 1.0 means the best user interaction with your site and 0.0 the worst interaction (like a bot). You can see some examples of use in ReCaptcha documentation.