diff --git a/application/controllers/Settings.php b/application/controllers/Settings.php
new file mode 100644
index 00000000..0976ea64
--- /dev/null
+++ b/application/controllers/Settings.php
@@ -0,0 +1,186 @@
+<?php defined('BASEPATH') or exit('No direct script access allowed');
+
+/* ----------------------------------------------------------------------------
+ * Easy!Appointments - Open Source Web Scheduler
+ *
+ * @package     EasyAppointments
+ * @author      A.Tselegidis <alextselegidis@gmail.com>
+ * @copyright   Copyright (c) 2013 - 2020, Alex Tselegidis
+ * @license     https://opensource.org/licenses/GPL-3.0 - GPLv3
+ * @link        https://easyappointments.org
+ * @since       v1.5.0
+ * ---------------------------------------------------------------------------- */
+
+/**
+ * Settings controller. 
+ * 
+ * Handles settings related operations.
+ *
+ * @package Controllers 
+ */
+class Settings extends EA_Controller {
+    /**
+     * @var array
+     */
+    protected $permissions;
+    
+    /**
+     * Calendar constructor.
+     */
+    public function __construct()
+    {
+        parent::__construct(); 
+        
+        $this->load->model('appointments_model'); 
+        $this->load->model('customers_model'); 
+        $this->load->model('services_model'); 
+        $this->load->model('providers_model');
+
+        $this->load->library('google_sync');
+        $this->load->library('notifications');
+        $this->load->library('synchronization');
+        $this->load->library('timezones');
+
+        $role_slug = session('role_slug');
+
+        if ($role_slug)
+        {
+            $this->permissions = $this->roles_model->get_permissions_by_slug($role_slug);
+        }
+    }
+
+    /**
+     * Save a setting or multiple settings in the database.
+     */
+    public function ajax_save_settings()
+    {
+        try
+        {
+            $type = request('type');
+
+            if ($type == SETTINGS_SYSTEM)
+            {
+                if ($this->permissions[PRIV_SYSTEM_SETTINGS]['edit'] == FALSE)
+                {
+                    throw new Exception('You do not have the required permissions for this task.');
+                }
+
+                $settings = json_decode(request('settings', FALSE), TRUE);
+
+                // Check if phone number settings are valid.
+
+                $phone_number_required = FALSE;
+
+                $phone_number_shown = FALSE;
+
+                foreach ($settings as $setting)
+                {
+                    if ($setting['name'] === 'require_phone_number')
+                    {
+                        $phone_number_required = $setting['value'];
+                    }
+
+                    if ($setting['name'] === 'show_phone_number')
+                    {
+                        $phone_number_shown = $setting['value'];
+                    }
+                }
+
+                if ($phone_number_required && ! $phone_number_shown)
+                {
+                    throw new RuntimeException('You cannot hide the phone number in the booking form while it\'s also required!');
+                }
+
+                foreach ($settings as $setting)
+                {
+                    $existing_setting = $this->settings_model->query()->where('name', $setting['name'])->get()->row_array();
+
+                    if ( ! empty($existing_setting))
+                    {
+                        $setting['id'] = $existing_setting['id'];
+                    }
+
+                    $this->settings_model->save($setting);
+                }
+            }
+            else if ($type == SETTINGS_USER)
+            {
+                if ($this->permissions[PRIV_USER_SETTINGS]['edit'] == FALSE)
+                {
+                    throw new Exception('You do not have the required permissions for this task.');
+                }
+
+                $settings = json_decode(request('settings'), TRUE);
+
+                $this->users_model->save($settings);
+
+                session([
+                    'user_email' => $settings['email'],
+                    'username' => $settings['settings']['username'],
+                    'timezone' => $settings['timezone'],
+                ]);
+            }
+
+            response();
+        }
+        catch (Throwable $e)
+        {
+            json_exception($e);
+        }
+    }
+
+    /**
+     * This method checks whether the username already exists in the database.
+     */
+    public function ajax_validate_username()
+    {
+        try
+        {
+            // We will only use the function in the admins_model because it is sufficient for the rest user types for
+            // now (providers, secretaries).
+
+            $username = request('username');
+
+            $user_id = request('user_id');
+
+            $is_valid = $this->admins_model->validate_username($username, $user_id);
+
+            json_response([
+                'is_valid' => $is_valid,
+            ]);
+        }
+        catch (Throwable $e)
+        {
+            json_exception($e);
+        }
+    }
+
+    /**
+     * Apply global working plan to all providers.
+     */
+    public function ajax_apply_global_working_plan()
+    {
+        try
+        {
+            if ($this->permissions[PRIV_SYSTEM_SETTINGS]['edit'] == FALSE)
+            {
+                throw new Exception('You do not have the required permissions for this task.');
+            }
+
+            $working_plan = request('working_plan');
+
+            $providers = $this->providers_model->get();
+
+            foreach ($providers as $provider)
+            {
+                $this->providers_model->set_setting($provider['id'], 'working_plan', $working_plan);
+            }
+
+            response();
+        }
+        catch (Throwable $e)
+        {
+            json_exception($e);
+        }
+    }
+}