CodeIgniter 4 Integration of Google reCaptcha v2

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Inside this article we will see the concept of CodeIgniter 4 Integration of Google reCaptcha v2 Tutorial. Google reCAPTCHA is a CAPTCHA system that enables web hosts to distinguish between human and automated access to websites.

Tutorial will help you to understand the integration of google recaptcha v2 in CodeIgniter 4. This will be step by step guide article.

Google reCaptcha that provide security against hackers and sticks or curl requests. It assures that a computer user is a human. It is the best and most used captcha system available where users are only required to click on a checkbox and in some cases select some similar images related to conman question.

Learn More –

Note*: For this article, CodeIgniter v4.1 setup has been installed. May be when you are seeing, version will be updated. CodeIgniter 4.x still is in development mode.

Let’ get started.

Download & Install CodeIgniter 4 Setup

We need to download & install CodeIgniter 4 application setup to system.

To set application we have multiple options to proceed.

Here are the following ways to download and install CodeIgniter 4 –

  • Manual Download
  • Composer Installation
  • Clone Github repository of CodeIgniter 4

Complete introduction of CodeIgniter 4 basics – Click here to go. After going through this article you can easily download & install setup.

Here is the command to install via composer –

$ composer create-project codeigniter4/appstarter codeigniter-4

Assuming you have successfully installed application into your local system.

Turn Development Mode On

When we install CodeIgniter 4, we have env file at root. To use the environment variables means using variables at global scope we need to do env to .env

Open project in terminal

$ cp env .env

Above command will create a copy of env file to .env file. Now we are ready to use environment variables.

CodeIgniter starts up in production mode by default. Let’s do it in development mode. So that while working if we get any error then error will show up.

# CI_ENVIRONMENT = production

 // Do it to 
CI_ENVIRONMENT = development

Now application is in development mode.

Google reCaptcha Credentials

Open browser and hit this link, it will need to login via your google account. Please login to create google recaptcha credentials.

You need to do these,

  • Label name
  • Select reCaptcha version type
  • Domain to be linked

Click on Submit

Copy your Site Key and Secret Key from here.

Settings Environment Variables

Open .env file from application and add these keys into it.





Create Controller

Open project into terminal and run this spark command to create controller.

$ php spark make:controller Register --suffix

It will create RegisterController.php file inside /app/Controllers folder.

Open RegisterController.php write this complete code into it.


namespace App\Controllers;

use App\Controllers\BaseController;

class RegisterController extends BaseController
    public function index()
        return view('register');

    public function googleCaptachStore()
        $recaptchaResponse = trim($this->request->getVar('g-recaptcha-response'));

        // form data

        $secret = env('RECAPTCHAV3_SITEKEY');

        $credential = array(
            'secret' => $secret,
            'response' => $recaptchaResponse

        $verify = curl_init();
        curl_setopt($verify, CURLOPT_URL, "");
        curl_setopt($verify, CURLOPT_POST, true);
        curl_setopt($verify, CURLOPT_POSTFIELDS, http_build_query($credential));
        curl_setopt($verify, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($verify, CURLOPT_RETURNTRANSFER, true);
        $response = curl_exec($verify);

        $status = json_decode($response, true);

        $session = session();

        if ($status['success']) {

            $session->setFlashdata('msg', 'Form has been successfully submitted');
        } else {

            $session->setFlashdata('msg', 'Please check your inputs');

        return redirect()->to('form');

Layout Template


Create a file with name register.php inside /app/Views folder.

Open register.php and write this code into it.

<!doctype html>
<html lang="en">

    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
    <title>Codeigniter 4 Integration of Google Recaptcha v2</title>
    <link rel="stylesheet" href="">
    <script src=""></script>
    <script src=''></script>
        .error {
            color: red;

    <div class="container" style="margin-top:30px;">

        <div class="row">
            <div class="col-md-9">
                <h3>User Form</h3>
                <div class="error"><strong><?= session('msg') ?></strong></div>
                <br />
                <form method="post" action="<?= base_url('form-submit') ?>">
                    <div class="form-group">
                        <label for="formGroupExampleInput">Name</label>
                        <input type="text" name="name" class="form-control" id="formGroupExampleInput" placeholder="Please enter name">
                    <div class="form-group">
                        <label for="email">Email Id</label>
                        <input type="text" name="email" class="form-control" id="email" placeholder="Please enter email id">
                    <div class="form-group">
                        <label for="mobile_number">Mobile Number</label>
                        <input type="text" name="mobile_number" class="form-control" id="mobile_number" placeholder="Please enter mobile number" maxlength="10">
                    <div class="g-recaptcha" data-sitekey="<?= env('RECAPTCHAV3_SITEKEY') ?>"></div>
                    <br />
                    <div class="form-group">
                        <button type="submit" id="send_form" class="btn btn-success">Submit</button>


Add Route

Open Routes.php from /app/Config folder.


$routes->get('form', 'RegisterController::index');
$routes->post('form-submit', 'RegisterController::googleCaptachStore');


Application Testing

Start development server:

$ php spark serve

URL – http://localhost:8080/form

Form submit without inputs

Form submit with inputs

We hope this article helped you to learn CodeIgniter 4 Integration of Google reCaptcha v2 Tutorial in a very detailed way.

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