diff --git a/inc/abstract-location.php b/inc/abstract-location.php
new file mode 100644
index 0000000..b8d57cf
--- /dev/null
+++ b/inc/abstract-location.php
@@ -0,0 +1,85 @@
+<?php
+/**
+ * @package ogre-captcha
+ * @author cleverogre
+ * @copyright 2026 CleverOgre
+ * @license GLP-3.0-or-later
+ * @version 0.0.0
+ * @since 0.0.0
+ */
+
+namespace Ogre\Captcha;
+
+use Ogre\Singleton;
+use Ogre\Captcha as Plugin;
+use Ogre\Captcha\Settings;
+use WP_Error;
+
+defined('ABSPATH') || exit;
+
+abstract class Location {
+    use Singleton;
+
+    public const ERROR_EMPTY_TOKEN = 'empty_captcha_token';
+    public const ERROR_INVALID_CAPTCHA = 'invalid_captcha_result';
+
+    protected string $name;
+
+    protected function __construct(string $name) {
+        $this->name = $name;
+        add_action('init', [$this, 'init']);
+    }
+
+    public function enabled():bool {
+        return Settings::is_form_location_enabled($this->name);
+    }
+
+    public function init():void {
+		if (is_multisite()) {
+			$blog_id = get_current_blog_id();
+			switch_to_blog($blog_id);
+        }
+        $enabled = $this->enabled();
+        if (is_multisite()) {
+			restore_current_blog();
+        }
+        if (!$enabled) return;
+
+        $this->activate();
+    }
+
+    abstract public function activate():void;
+
+    public function render():void {
+        Widget::render();
+    }
+
+    public function process(WP_Error $errors):void {
+        if (!Settings::is_connected()) return;
+
+        $token = Widget::get_token();
+        if (empty($token)) {
+            $errors->add(self::ERROR_EMPTY_TOKEN, Plugin::__('<strong>Error:</strong> Please complete CAPTCHA verification.'));
+            return;
+        }
+
+        if (!API::verify($token)) {
+            $errors->add(self::ERROR_INVALID_CAPTCHA, Plugin::__('<strong>Error:</strong> Your answer was incorrect - please try again.'));
+            return;
+        }
+    }
+
+    protected function print_errors(WP_Error $errors):void {
+        if (!$errors->has_errors()) return;
+        ob_start();
+        echo '<ul>';
+        foreach ($errors->get_error_codes() as $code) {
+            foreach ($errors->get_error_messages($code) as $message) {
+                echo '<li>' . wp_kses($message, ['strong']) . '</li>';
+            }
+        }
+        echo '</ul>';
+        wp_die(ob_get_clean());
+    }
+
+}
diff --git a/inc/class-api.php b/inc/class-api.php
new file mode 100644
index 0000000..fd35f85
--- /dev/null
+++ b/inc/class-api.php
@@ -0,0 +1,55 @@
+<?php
+/**
+ * @package ogre-captcha
+ * @author cleverogre
+ * @copyright 2026 CleverOgre
+ * @license GLP-3.0-or-later
+ * @version 0.0.0
+ * @since 0.0.0
+ */
+
+namespace Ogre\Captcha;
+
+use Ogre\Captcha\Settings;
+
+defined('ABSPATH') || exit;
+
+final class API {
+
+    private static function transaction(string $url, array $data):array|string|bool {
+        $ch = curl_init($url);
+        curl_setopt($ch, CURLOPT_POSTFIELDS, wp_json_encode($data));
+        curl_setopt($ch, CURLOPT_HTTPHEADER, [
+            'content-type: application/json',
+            'accept: application/json',
+        ]);
+        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
+
+        $result = curl_exec($ch);
+        if ($result === false || !is_string($result) || empty($result)) return 'Invalid response';
+
+        $result = json_decode($result, true);
+        if (!is_array($result) || is_null($result)) return 'Invalid formatting';
+
+        if (isset($result['error']) && !empty($result['error'])) return $result['error'];
+        if (isset($result['success']) && is_bool($result['success'])) return $result['success'];
+        return $result;
+    }
+
+    private static function get_siteverify_url():string {
+        if (!Settings::is_connected()) return '';
+        return Settings::get_instance_url(Settings::get_site_key() . '/siteverify');
+    }
+
+    public static function verify(string $token):bool {
+        if (empty($token) || !Settings::is_connected()) return false;
+
+        $result = self::transaction(self::get_siteverify_url(), [
+            'secret' => Settings::get_secret_key(),
+            'response' => $token,
+        ]);
+
+        return is_bool($result) ? $result : false;
+    }
+
+}
diff --git a/inc/class-settings.php b/inc/class-settings.php
index 0c9a848..fd90748 100644
--- a/inc/class-settings.php
+++ b/inc/class-settings.php
@@ -23,7 +23,7 @@ final class Settings {
 
     public const LOCATION_LOGIN_PAGE = 'login_page';
     public const LOCATION_REGISTRATION_PAGE = 'registration_page';
-    public const LOCATION_LOST_PASSWORD_PAGE = 'lost_password_page';
+    public const LOCATION_LOST_PASSWORD_FORM = 'lost_password_page';
     public const LOCATION_LOGIN_FORM = 'login_form';
     public const LOCATION_COMMENT_FORM = 'comment_form';
     public const LOCATION_POST_PASSWORD_FORM = 'post_password_form';
@@ -43,8 +43,18 @@ final class Settings {
         return in_array($value, (array) self::get($name));
     }
 
-    public static function get_instance_url():string {
-        return !empty($value = (string) self::get('instance_url')) ? $value : self::DEFAULT_INSTANCE_URL;
+    public static function get_instance_url(string $path = ''):string {
+        $url = (string) self::get('instance_url');
+        if (empty($url)) $url = self::DEFAULT_INSTANCE_URL;
+        if (!wp_http_validate_url($url)) return '';
+        if (!empty($path)) {
+            $url = sprintf(
+                '%s/%s',
+                untrailingslashit(Settings::get_instance_url()),
+                $path
+            );
+        }
+        return $url;
     }
 
     public static function get_site_key():string {
@@ -55,32 +65,40 @@ final class Settings {
         return (string) self::get('secret_key');
     }
 
+    public static function is_connected():bool {
+        return !empty(self::get_site_key()) && !empty(self::get_secret_key());
+    }
+
     public static function get_form_locations():array {
         return (array) self::get('form_locations');
     }
 
+    public static function is_form_location_enabled(string $name):bool {
+        return in_array($name, self::get_form_locations());
+    }
+
     public static function is_login_page_enabled():bool {
-        return in_array(self::LOCATION_LOGIN_PAGE, self::get_form_locations());
+        return self::is_form_location_enabled(self::LOCATION_LOGIN_PAGE);
     }
 
     public static function is_registration_page_enabled():bool {
-        return in_array(self::LOCATION_REGISTRATION_PAGE, self::get_form_locations());
+        return self::is_form_location_enabled(self::LOCATION_REGISTRATION_PAGE);
     }
 
-    public static function is_lost_password_page_enabled():bool {
-        return in_array(self::LOCATION_LOST_PASSWORD_PAGE, self::get_form_locations());
+    public static function is_lost_password_form_enabled():bool {
+        return self::is_form_location_enabled(self::LOCATION_LOST_PASSWORD_FORM);
     }
 
     public static function is_login_form_enabled():bool {
-        return in_array(self::LOCATION_LOGIN_FORM, self::get_form_locations());
+        return self::is_form_location_enabled(self::LOCATION_LOGIN_FORM);
     }
 
     public static function is_comment_form_enabled():bool {
-        return in_array(self::LOCATION_COMMENT_FORM, self::get_form_locations());
+        return self::is_form_location_enabled(self::LOCATION_COMMENT_FORM);
     }
 
     public static function is_post_password_form_enabled():bool {
-        return in_array(self::LOCATION_POST_PASSWORD_FORM, self::get_form_locations());
+        return self::is_form_location_enabled(self::LOCATION_POST_PASSWORD_FORM);
     }
 
     public function menu() {
@@ -156,8 +174,8 @@ final class Settings {
                 'options' => [
                     self::LOCATION_LOGIN_PAGE => Plugin::__('Login page'),
                     self::LOCATION_REGISTRATION_PAGE => Plugin::__('Registration page'),
-                    self::LOCATION_LOST_PASSWORD_PAGE => Plugin::__('Lost password page'),
-                    self::LOCATION_LOGIN_FORM => Plugin::__('Custom login form'),
+                    self::LOCATION_LOST_PASSWORD_FORM => Plugin::__('Lost password page'),
+                    self::LOCATION_LOGIN_FORM => Plugin::__('Custom login form (requires Login Page)'),
                     self::LOCATION_COMMENT_FORM => Plugin::__('Comment form'),
                     self::LOCATION_POST_PASSWORD_FORM => Plugin::__('Password-protected posts and pages'),
                 ],
diff --git a/inc/class-widget.php b/inc/class-widget.php
new file mode 100644
index 0000000..7f46433
--- /dev/null
+++ b/inc/class-widget.php
@@ -0,0 +1,46 @@
+<?php
+/**
+ * @package ogre-captcha
+ * @author cleverogre
+ * @copyright 2026 CleverOgre
+ * @license GLP-3.0-or-later
+ * @version 0.0.0
+ * @since 0.0.0
+ */
+
+namespace Ogre\Captcha;
+
+use Ogre\Captcha\Settings;
+
+defined('ABSPATH') || exit;
+
+final class Widget {
+
+    private const SCRIPT_HANDLE = 'cap';
+    private const TOKEN_NAME = 'cap-token';
+    
+    private static function get_script_url():string {
+        if (!Settings::is_connected()) return '';
+        return Settings::get_instance_url('assets/widget.js');
+    }
+
+    public static function enqueue_script():void {
+        if (!Settings::is_connected() || wp_script_is(self::SCRIPT_HANDLE)) return;
+        wp_enqueue_script(self::SCRIPT_HANDLE, self::get_script_url());
+    }
+
+    public static function render(string $id = 'cap'):void {
+        if (!Settings::is_connected()) return;
+        self::enqueue_script();
+        printf(
+            '<cap-widget id="%s" required data-cap-api-endpoint="%s"></cap-widget>',
+            esc_attr($id),
+            esc_url(Settings::get_instance_url(Settings::get_site_key() . '/'))
+        );
+    }
+
+    public static function get_token():string {
+        return isset($_POST[self::TOKEN_NAME]) ? (string) $_POST[self::TOKEN_NAME] : '';
+    }
+
+}
diff --git a/inc/location/class-comment-form.php b/inc/location/class-comment-form.php
new file mode 100644
index 0000000..037b8f9
--- /dev/null
+++ b/inc/location/class-comment-form.php
@@ -0,0 +1,53 @@
+<?php
+/**
+ * @package ogre-captcha
+ * @author cleverogre
+ * @copyright 2026 CleverOgre
+ * @license GLP-3.0-or-later
+ * @version 0.0.0
+ * @since 0.0.0
+ */
+
+namespace Ogre\Captcha\Location;
+
+use Override;
+use Ogre\Captcha\Location;
+use Ogre\Captcha\Settings;
+use WP_Error;
+
+defined('ABSPATH') || exit;
+
+final class CommentForm extends Location {
+
+    protected function __construct() {
+        parent::__construct(Settings::LOCATION_COMMENT_FORM);
+    }
+
+    #[Override]
+    public function activate(): void
+    {
+        add_action('comment_form_after_fields', [$this, 'render'], 1);
+        add_filter('preprocess_comment', [$this, 'process_form']);
+    }
+    
+    public function process_form(array $commentdata):array {
+		// Don't process CAPTCHA for comment replies inside admin menu
+		if (isset($_REQUEST['action']) && 'replyto-comment' == $_REQUEST['action'] && (check_ajax_referer('replyto-comment', '_ajax_nonce', false) || check_ajax_referer('replyto-comment', '_ajax_nonce-replyto-comment', false))) {
+			return $comment;
+		}
+
+		// Don't do CAPTCHA for pingback/trackback
+		if ('' != $comment['comment_type'] && 'comment' != $comment['comment_type'] && 'review' != $comment['comment_type']) {
+			return $comment;
+		}
+
+        $errors = new WP_Error();
+        $this->process($errors);
+        $this->print_errors($errors);
+        
+        return $commentdata;
+    }
+
+}
+
+CommentForm::instance();
diff --git a/inc/location/class-login-form.php b/inc/location/class-login-form.php
new file mode 100644
index 0000000..ce1815e
--- /dev/null
+++ b/inc/location/class-login-form.php
@@ -0,0 +1,47 @@
+<?php
+/**
+ * @package ogre-captcha
+ * @author cleverogre
+ * @copyright 2026 CleverOgre
+ * @license GLP-3.0-or-later
+ * @version 0.0.0
+ * @since 0.0.0
+ */
+
+namespace Ogre\Captcha\Location;
+
+use Override;
+use Ogre\Captcha\Location;
+use Ogre\Captcha\Settings;
+
+defined('ABSPATH') || exit;
+
+final class LoginForm extends Location {
+
+    protected function __construct() {
+        parent::__construct(Settings::LOCATION_LOGIN_FORM);
+    }
+    
+    #[Override]
+    public function enabled(): bool
+    {
+        return is_user_logged_in() ? false : parent::enabled();
+    }
+
+    #[Override]
+    public function activate(): void
+    {
+        add_filter('login_form_middle', [$this, 'render_form'], 10, 2);
+        // NOTE: Requires login page processing
+    }
+
+    public function render_form(string $content, array $args):string {
+        ob_start();
+        $this->render();
+        $content .= ob_get_clean();
+        return $content;
+    }
+
+}
+
+LoginForm::instance();
diff --git a/inc/location/class-login-page.php b/inc/location/class-login-page.php
new file mode 100644
index 0000000..2e1e152
--- /dev/null
+++ b/inc/location/class-login-page.php
@@ -0,0 +1,61 @@
+<?php
+/**
+ * @package ogre-captcha
+ * @author cleverogre
+ * @copyright 2026 CleverOgre
+ * @license GLP-3.0-or-later
+ * @version 0.0.0
+ * @since 0.0.0
+ */
+
+namespace Ogre\Captcha\Location;
+
+use Override;
+use Ogre\Captcha\Location;
+use Ogre\Captcha\Settings;
+use WP_Error;
+use WP_User;
+
+defined('ABSPATH') || exit;
+
+final class LoginPage extends Location {
+
+    protected function __construct() {
+        parent::__construct(Settings::LOCATION_LOGIN_PAGE);
+    }
+    
+    #[Override]
+    public function enabled(): bool
+    {
+        return is_user_logged_in() ? false : parent::enabled();
+    }
+
+    #[Override]
+    public function activate(): void
+    {
+        add_action('login_form', [$this, 'render']);
+        add_filter('shake_error_codes', [$this, 'shake_error_codes']);
+        add_filter('authenticate', [$this, 'process_form'], 20, 1);
+    }
+
+    public function shake_error_codes(array $shake_error_codes):array {
+        return array_merge(
+            $shake_error_codes,
+            [
+                self::ERROR_EMPTY_TOKEN,
+                self::ERROR_INVALID_CAPTCHA,
+            ]
+        );
+    }
+    
+    public function process_form(WP_User|WP_Error $user):WP_User|WP_Error {
+        if (is_wp_error($user)) return $user;
+        if (!isset($_POST['log']) || !isset($_POST['pwd'])) return $user;
+        $errors = new WP_Error();
+        $this->process($errors);
+        return $errors->has_errors() ? $errors : $user;
+    }
+
+}
+
+LoginPage::instance();
diff --git a/inc/location/class-lost-password-form.php b/inc/location/class-lost-password-form.php
new file mode 100644
index 0000000..3c35da9
--- /dev/null
+++ b/inc/location/class-lost-password-form.php
@@ -0,0 +1,46 @@
+<?php
+/**
+ * @package ogre-captcha
+ * @author cleverogre
+ * @copyright 2026 CleverOgre
+ * @license GLP-3.0-or-later
+ * @version 0.0.0
+ * @since 0.0.0
+ */
+
+namespace Ogre\Captcha\Location;
+
+use Override;
+use Ogre\Captcha\Location;
+use Ogre\Captcha\Settings;
+use WP_Error;
+use WP_User;
+
+defined('ABSPATH') || exit;
+
+final class LostPasswordForm extends Location {
+
+    protected function __construct() {
+        parent::__construct(Settings::LOCATION_LOST_PASSWORD_FORM);
+    }
+    
+    #[Override]
+    public function enabled(): bool
+    {
+        return is_user_logged_in() ? false : parent::enabled();
+    }
+
+    #[Override]
+    public function activate(): void
+    {
+        add_action('lostpassword_form', [$this, 'render']);
+        add_action('lostpassword_post', [$this, 'process_form']);
+    }
+
+    public function process_form(WP_Error $errors, WP_User|bool $user_data):void {
+        $this->process($errors);
+    }
+
+}
+
+LostPasswordForm::instance();
diff --git a/inc/location/class-post-password-form.php b/inc/location/class-post-password-form.php
new file mode 100644
index 0000000..c834a4b
--- /dev/null
+++ b/inc/location/class-post-password-form.php
@@ -0,0 +1,49 @@
+<?php
+/**
+ * @package ogre-captcha
+ * @author cleverogre
+ * @copyright 2026 CleverOgre
+ * @license GLP-3.0-or-later
+ * @version 0.0.0
+ * @since 0.0.0
+ */
+
+namespace Ogre\Captcha\Location;
+
+use Override;
+use Ogre\Captcha\Location;
+use Ogre\Captcha\Settings;
+use WP_Error;
+use WP_Post;
+
+defined('ABSPATH') || exit;
+
+final class PostPasswordForm extends Location {
+
+    protected function __construct() {
+        parent::__construct(Settings::LOCATION_POST_PASSWORD_FORM);
+    }
+
+    #[Override]
+    public function activate(): void
+    {
+        add_filter('the_password_form', [$this, 'render_form']);
+        add_action('login_form_postpass', [$this, 'process_form']);
+    }
+
+    public function render_form(string $output, WP_Post $post, string $invalid_password):string {
+        ob_start();
+        $this->render();
+        $output .= ob_get_clean();
+        return $output;
+    }
+
+    public function process_form():void {
+        $errors = new WP_Error();
+        $this->process($errors);
+        $this->print_errors($errors);
+    }
+
+}
+
+PostPasswordForm::instance();
diff --git a/inc/location/class-registration-page.php b/inc/location/class-registration-page.php
new file mode 100644
index 0000000..63110f2
--- /dev/null
+++ b/inc/location/class-registration-page.php
@@ -0,0 +1,56 @@
+<?php
+/**
+ * @package ogre-captcha
+ * @author cleverogre
+ * @copyright 2026 CleverOgre
+ * @license GLP-3.0-or-later
+ * @version 0.0.0
+ * @since 0.0.0
+ */
+
+namespace Ogre\Captcha\Location;
+
+use Override;
+use Ogre\Captcha\Location;
+use Ogre\Captcha\Settings;
+use WP_Error;
+
+defined('ABSPATH') || exit;
+
+final class RegistrationPage extends Location {
+
+    protected function __construct() {
+        parent::__construct(Settings::LOCATION_REGISTRATION_PAGE);
+    }
+    
+    #[Override]
+    public function enabled(): bool
+    {
+        return is_user_logged_in() ? false : parent::enabled();
+    }
+
+    #[Override]
+    public function activate(): void
+    {
+        if (is_multisite()) {
+            add_action('signup_extra_fields', [$this, 'render']);
+            add_filter('wpmu_validate_user_signup', [$this, 'process_multisite_form']);
+        } else {
+		    add_action('register_form', [$this, 'render']);
+        }
+        add_filter('registration_errors', [$this, 'process_form'], 10, 3);
+    }
+
+    public function process_multisite_form(array $result):array {
+        $this->process($result['errors']);
+        return $result;
+    }
+
+    public function process_form(WP_Error $errors, string $sanitized_user_login, string $user_email):WP_Error {
+        $this->process($errors);
+        return $errors;
+    }
+
+}
+
+RegistrationPage::instance();
diff --git a/ogre-captcha.php b/ogre-captcha.php
index e1c73f3..b69cfe0 100644
--- a/ogre-captcha.php
+++ b/ogre-captcha.php
@@ -1,6 +1,6 @@
 <?php
 /**
- * Plugin
+ * Ogre CAPTCHA
  *
  * @package ogre-captcha
  * @author cleverogre
@@ -40,6 +40,15 @@ final class Captcha extends Plugin {
 
         $this->add_files([
             'inc/class-settings.php',
+            'inc/class-api.php',
+            'inc/class-widget.php',
+            'inc/abstract-location.php',
+            'inc/location/class-comment-form.php',
+            'inc/location/class-login-form.php',
+            'inc/location/class-login-page.php',
+            'inc/location/class-lost-password-form.php',
+            'inc/location/class-post-password-form.php',
+            'inc/location/class-registration-page.php',
         ]);
     }