diff --git a/CHANGELOG.md b/CHANGELOG.md
index 06be6cc4..20c90b76 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -43,6 +43,7 @@ developers to maintain and readjust their custom modifications on the main proje
 - Create new layout structure for the markup, so that common HTML markup is being reused (#1152)
 - Have an option to hide customer data fields during booking (#1081)
 - Add a SECURITY.md file to the repository (#1122)
+- Add support for custom fields on customers (#1133)
 
 ### Changed
 
diff --git a/application/controllers/Customers.php b/application/controllers/Customers.php
index a57c123c..a8aabef0 100644
--- a/application/controllers/Customers.php
+++ b/application/controllers/Customers.php
@@ -18,7 +18,8 @@
  *
  * @package Controllers
  */
-class Customers extends EA_Controller {
+class Customers extends EA_Controller
+{
     /**
      * Customers constructor.
      */
@@ -49,10 +50,8 @@ class Customers extends EA_Controller {
 
         $user_id = session('user_id');
 
-        if (cannot('view', PRIV_CUSTOMERS))
-        {
-            if ($user_id)
-            {
+        if (cannot('view', PRIV_CUSTOMERS)) {
+            if ($user_id) {
                 abort(403, 'Forbidden');
             }
 
@@ -75,8 +74,7 @@ class Customers extends EA_Controller {
 
         $secretary_providers = [];
 
-        if ($role_slug === DB_SLUG_SECRETARY)
-        {
+        if ($role_slug === DB_SLUG_SECRETARY) {
             $secretary = $this->secretaries_model->find($user_id);
 
             $secretary_providers = $secretary['providers'];
@@ -88,7 +86,7 @@ class Customers extends EA_Controller {
             'date_format' => $date_format,
             'time_format' => $time_format,
             'timezones' => $this->timezones->to_array(),
-            'secretary_providers' => $secretary_providers,
+            'secretary_providers' => $secretary_providers
         ]);
 
         html_vars([
@@ -105,21 +103,45 @@ class Customers extends EA_Controller {
             'require_address' => $require_address,
             'require_city' => $require_city,
             'require_zip_code' => $require_zip_code,
-            'available_languages' => config('available_languages'),
+            'available_languages' => config('available_languages')
         ]);
 
         $this->load->view('pages/customers');
     }
 
+    /**
+     * Find a customer.
+     */
+    public function find()
+    {
+        try {
+            if (cannot('view', PRIV_CUSTOMERS)) {
+                abort(403, 'Forbidden');
+            }
+
+            $user_id = session('user_id');
+
+            $customer_id = request('customer_id');
+
+            if (!$this->permissions->has_customer_access($user_id, $customer_id)) {
+                abort(403, 'Forbidden');
+            }
+
+            $customer = $this->customers_model->find($customer_id);
+
+            json_response($customer);
+        } catch (Throwable $e) {
+            json_exception($e);
+        }
+    }
+
     /**
      * Filter customers by the provided keyword.
      */
     public function search()
     {
-        try
-        {
-            if (cannot('view', PRIV_CUSTOMERS))
-            {
+        try {
+            if (cannot('view', PRIV_CUSTOMERS)) {
                 abort(403, 'Forbidden');
             }
 
@@ -135,10 +157,8 @@ class Customers extends EA_Controller {
 
             $user_id = session('user_id');
 
-            foreach ($customers as $index => &$customer)
-            {
-                if ( ! $this->permissions->has_customer_access($user_id, $customer['id']))
-                {
+            foreach ($customers as $index => &$customer) {
+                if (!$this->permissions->has_customer_access($user_id, $customer['id'])) {
                     unset($customers[$index]);
 
                     continue;
@@ -146,21 +166,15 @@ class Customers extends EA_Controller {
 
                 $appointments = $this->appointments_model->get(['id_users_customer' => $customer['id']]);
 
-                foreach ($appointments as &$appointment)
-                {
-                    $this->appointments_model->load($appointment, [
-                        'service',
-                        'provider',
-                    ]);
+                foreach ($appointments as &$appointment) {
+                    $this->appointments_model->load($appointment, ['service', 'provider']);
                 }
 
                 $customer['appointments'] = $appointments;
             }
 
             json_response(array_values($customers));
-        }
-        catch (Throwable $e)
-        {
+        } catch (Throwable $e) {
             json_exception($e);
         }
     }
@@ -170,15 +184,12 @@ class Customers extends EA_Controller {
      */
     public function store()
     {
-        try
-        {
-            if (cannot('add', PRIV_CUSTOMERS))
-            {
+        try {
+            if (cannot('add', PRIV_CUSTOMERS)) {
                 abort(403, 'Forbidden');
             }
 
-            if (session('role_slug') !== DB_SLUG_ADMIN && setting('limit_customer_visibility'))
-            {
+            if (session('role_slug') !== DB_SLUG_ADMIN && setting('limit_customer_visibility')) {
                 abort(403);
             }
 
@@ -196,6 +207,11 @@ class Customers extends EA_Controller {
                 'notes',
                 'timezone',
                 'language',
+                'custom_field_1',
+                'custom_field_2',
+                'custom_field_3',
+                'custom_field_4',
+                'custom_field_5'
             ]);
 
             $customer_id = $this->customers_model->save($customer);
@@ -205,12 +221,10 @@ class Customers extends EA_Controller {
             $this->webhooks_client->trigger(WEBHOOK_CUSTOMER_SAVE, $customer);
 
             json_response([
-                'success' => TRUE,
+                'success' => true,
                 'id' => $customer_id
             ]);
-        }
-        catch (Throwable $e)
-        {
+        } catch (Throwable $e) {
             json_exception($e);
         }
     }
@@ -220,10 +234,8 @@ class Customers extends EA_Controller {
      */
     public function update()
     {
-        try
-        {
-            if (cannot('edit', PRIV_CUSTOMERS))
-            {
+        try {
+            if (cannot('edit', PRIV_CUSTOMERS)) {
                 abort(403, 'Forbidden');
             }
 
@@ -231,8 +243,7 @@ class Customers extends EA_Controller {
 
             $customer = request('customer');
 
-            if ( ! $this->permissions->has_customer_access($user_id, $customer['id']))
-            {
+            if (!$this->permissions->has_customer_access($user_id, $customer['id'])) {
                 abort(403, 'Forbidden');
             }
 
@@ -249,6 +260,11 @@ class Customers extends EA_Controller {
                 'notes',
                 'timezone',
                 'language',
+                'custom_field_1',
+                'custom_field_2',
+                'custom_field_3',
+                'custom_field_4',
+                'custom_field_5'
             ]);
 
             $customer_id = $this->customers_model->save($customer);
@@ -258,12 +274,10 @@ class Customers extends EA_Controller {
             $this->webhooks_client->trigger(WEBHOOK_CUSTOMER_SAVE, $customer);
 
             json_response([
-                'success' => TRUE,
+                'success' => true,
                 'id' => $customer_id
             ]);
-        }
-        catch (Throwable $e)
-        {
+        } catch (Throwable $e) {
             json_exception($e);
         }
     }
@@ -273,10 +287,8 @@ class Customers extends EA_Controller {
      */
     public function destroy()
     {
-        try
-        {
-            if (cannot('delete', PRIV_CUSTOMERS))
-            {
+        try {
+            if (cannot('delete', PRIV_CUSTOMERS)) {
                 abort(403, 'Forbidden');
             }
 
@@ -284,8 +296,7 @@ class Customers extends EA_Controller {
 
             $customer_id = request('customer_id');
 
-            if ( ! $this->permissions->has_customer_access($user_id, $customer_id))
-            {
+            if (!$this->permissions->has_customer_access($user_id, $customer_id)) {
                 abort(403, 'Forbidden');
             }
 
@@ -296,42 +307,9 @@ class Customers extends EA_Controller {
             $this->webhooks_client->trigger(WEBHOOK_CUSTOMER_DELETE, $customer);
 
             json_response([
-                'success' => TRUE,
+                'success' => true
             ]);
-        }
-        catch (Throwable $e)
-        {
-            json_exception($e);
-        }
-    }
-
-    /**
-     * Find a customer.
-     */
-    public function find()
-    {
-        try
-        {
-            if (cannot('view', PRIV_CUSTOMERS))
-            {
-                abort(403, 'Forbidden');
-            }
-
-            $user_id = session('user_id');
-
-            $customer_id = request('customer_id');
-
-            if ( ! $this->permissions->has_customer_access($user_id, $customer_id))
-            {
-                abort(403, 'Forbidden');
-            }
-
-            $customer = $this->customers_model->find($customer_id);
-
-            json_response($customer);
-        }
-        catch (Throwable $e)
-        {
+        } catch (Throwable $e) {
             json_exception($e);
         }
     }
diff --git a/application/language/arabic/translations_lang.php b/application/language/arabic/translations_lang.php
index 1aa6b9fd..2d473dc8 100755
--- a/application/language/arabic/translations_lang.php
+++ b/application/language/arabic/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/bulgarian/translations_lang.php b/application/language/bulgarian/translations_lang.php
index c919270b..c76cfeaf 100755
--- a/application/language/bulgarian/translations_lang.php
+++ b/application/language/bulgarian/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/catalan/translations_lang.php b/application/language/catalan/translations_lang.php
index fa3e2147..6b68fe9e 100644
--- a/application/language/catalan/translations_lang.php
+++ b/application/language/catalan/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/chinese/translations_lang.php b/application/language/chinese/translations_lang.php
index 5a972e7c..0c2d8efe 100755
--- a/application/language/chinese/translations_lang.php
+++ b/application/language/chinese/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/croatian/translations_lang.php b/application/language/croatian/translations_lang.php
index 62d4f583..21244e59 100644
--- a/application/language/croatian/translations_lang.php
+++ b/application/language/croatian/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/czech/translations_lang.php b/application/language/czech/translations_lang.php
index 2f68d2eb..30c868d4 100644
--- a/application/language/czech/translations_lang.php
+++ b/application/language/czech/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/danish/translations_lang.php b/application/language/danish/translations_lang.php
index 868521da..efc43a86 100755
--- a/application/language/danish/translations_lang.php
+++ b/application/language/danish/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/dutch/translations_lang.php b/application/language/dutch/translations_lang.php
index 63015f94..ad03ef53 100755
--- a/application/language/dutch/translations_lang.php
+++ b/application/language/dutch/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/english/translations_lang.php b/application/language/english/translations_lang.php
index 2d931dba..d721dffd 100755
--- a/application/language/english/translations_lang.php
+++ b/application/language/english/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/estonian/translations_lang.php b/application/language/estonian/translations_lang.php
index 09c14b66..63a8d36f 100644
--- a/application/language/estonian/translations_lang.php
+++ b/application/language/estonian/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/finnish/translations_lang.php b/application/language/finnish/translations_lang.php
index 669ac321..6ee251e8 100755
--- a/application/language/finnish/translations_lang.php
+++ b/application/language/finnish/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/french/translations_lang.php b/application/language/french/translations_lang.php
index b6c320a0..f7448097 100755
--- a/application/language/french/translations_lang.php
+++ b/application/language/french/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/german/translations_lang.php b/application/language/german/translations_lang.php
index 8450646c..745fa458 100755
--- a/application/language/german/translations_lang.php
+++ b/application/language/german/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/greek/translations_lang.php b/application/language/greek/translations_lang.php
index a9322c72..99588172 100755
--- a/application/language/greek/translations_lang.php
+++ b/application/language/greek/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/hebrew/translations_lang.php b/application/language/hebrew/translations_lang.php
index 78e8c287..fd575159 100644
--- a/application/language/hebrew/translations_lang.php
+++ b/application/language/hebrew/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/hindi/translations_lang.php b/application/language/hindi/translations_lang.php
index 21b9387b..97df25f2 100755
--- a/application/language/hindi/translations_lang.php
+++ b/application/language/hindi/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/hungarian/translations_lang.php b/application/language/hungarian/translations_lang.php
index c2c75f34..2e79f03d 100755
--- a/application/language/hungarian/translations_lang.php
+++ b/application/language/hungarian/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/italian/translations_lang.php b/application/language/italian/translations_lang.php
index 9a1f0172..93d6b75a 100755
--- a/application/language/italian/translations_lang.php
+++ b/application/language/italian/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/japanese/translations_lang.php b/application/language/japanese/translations_lang.php
index e3339b19..7467722d 100755
--- a/application/language/japanese/translations_lang.php
+++ b/application/language/japanese/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/luxembourgish/translations_lang.php b/application/language/luxembourgish/translations_lang.php
index c1b6f34a..3a2ef359 100755
--- a/application/language/luxembourgish/translations_lang.php
+++ b/application/language/luxembourgish/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/marathi/translations_lang.php b/application/language/marathi/translations_lang.php
index d836296c..3a733535 100644
--- a/application/language/marathi/translations_lang.php
+++ b/application/language/marathi/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/persian/translations_lang.php b/application/language/persian/translations_lang.php
index 7d6a6609..e3e8d9df 100644
--- a/application/language/persian/translations_lang.php
+++ b/application/language/persian/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/polish/translations_lang.php b/application/language/polish/translations_lang.php
index 152c54b2..6579b25d 100755
--- a/application/language/polish/translations_lang.php
+++ b/application/language/polish/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/portuguese-br/translations_lang.php b/application/language/portuguese-br/translations_lang.php
index e8afc35a..2a7c8c95 100755
--- a/application/language/portuguese-br/translations_lang.php
+++ b/application/language/portuguese-br/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/portuguese/translations_lang.php b/application/language/portuguese/translations_lang.php
index aa57636a..26af230b 100755
--- a/application/language/portuguese/translations_lang.php
+++ b/application/language/portuguese/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/romanian/translations_lang.php b/application/language/romanian/translations_lang.php
index 0ff129ee..76499148 100755
--- a/application/language/romanian/translations_lang.php
+++ b/application/language/romanian/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/russian/translations_lang.php b/application/language/russian/translations_lang.php
index fe627163..51e9c291 100644
--- a/application/language/russian/translations_lang.php
+++ b/application/language/russian/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/serbian/translations_lang.php b/application/language/serbian/translations_lang.php
index 193bdc74..e0569d02 100644
--- a/application/language/serbian/translations_lang.php
+++ b/application/language/serbian/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/slovak/translations_lang.php b/application/language/slovak/translations_lang.php
index 6694049b..7cd6b86b 100755
--- a/application/language/slovak/translations_lang.php
+++ b/application/language/slovak/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/spanish/translations_lang.php b/application/language/spanish/translations_lang.php
index d41409fc..30a70e75 100755
--- a/application/language/spanish/translations_lang.php
+++ b/application/language/spanish/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/swedish/translations_lang.php b/application/language/swedish/translations_lang.php
index d714a206..f99f6a6b 100644
--- a/application/language/swedish/translations_lang.php
+++ b/application/language/swedish/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/language/turkish/translations_lang.php b/application/language/turkish/translations_lang.php
index 6546d518..7bd07f72 100755
--- a/application/language/turkish/translations_lang.php
+++ b/application/language/turkish/translations_lang.php
@@ -446,5 +446,7 @@ $lang['blocked_periods'] = 'Blocked Periods';
 $lang['blocked_period_save'] = 'Blocked Period Save';
 $lang['blocked_period_delete'] = 'Blocked Period Delete';
 $lang['blocked_periods_hint'] = 'Define periods of time where public bookings will be disabled for all providers (e.g. closed dates, holidays etc.).';
-$lang['auxiliary_field'] = 'Auxiliary Field';
+$lang['custom_field'] = 'Custom Field';
+$lang['custom_fields'] = 'Custom Fields';
+$lang['label'] = 'Label';
 // End
diff --git a/application/migrations/050_add_custom_fields_columns_to_users_table.php b/application/migrations/050_add_custom_fields_columns_to_users_table.php
new file mode 100644
index 00000000..ee162015
--- /dev/null
+++ b/application/migrations/050_add_custom_fields_columns_to_users_table.php
@@ -0,0 +1,56 @@
+<?php defined('BASEPATH') or exit('No direct script access allowed');
+
+/* ----------------------------------------------------------------------------
+ * Easy!Appointments - Online Appointment Scheduler
+ *
+ * @package     EasyAppointments
+ * @author      A.Tselegidis <alextselegidis@gmail.com>
+ * @copyright   Copyright (c) Alex Tselegidis
+ * @license     https://opensource.org/licenses/GPL-3.0 - GPLv3
+ * @link        https://easyappointments.org
+ * @since       v1.4.0
+ * ---------------------------------------------------------------------------- */
+
+class Migration_Add_custom_fields_columns_to_users_table extends EA_Migration
+{
+    /**
+     * @var int
+     */
+    private const FIELD_NUMBER = 5;
+
+    /**
+     * Upgrade method.
+     */
+    public function up()
+    {
+        for ($i = self::FIELD_NUMBER; $i > 0; $i--) {
+            $field_name = 'custom_field_' . $i;
+
+            if (!$this->db->field_exists($field_name, 'users')) {
+                $fields = [
+                    $field_name => [
+                        'type' => 'TEXT',
+                        'null' => true,
+                        'after' => 'language'
+                    ]
+                ];
+
+                $this->dbforge->add_column('users', $fields);
+            }
+        }
+    }
+
+    /**
+     * Downgrade method.
+     */
+    public function down()
+    {
+        for ($i = self::FIELD_NUMBER; $i > 0; $i--) {
+            $field_name = 'custom_fields_' . $i;
+
+            if ($this->db->field_exists($field_name, 'users')) {
+                $this->dbforge->drop_column('users', $field_name);
+            }
+        }
+    }
+}
diff --git a/application/migrations/051_insert_custom_field_rows_to_settings_table.php b/application/migrations/051_insert_custom_field_rows_to_settings_table.php
new file mode 100644
index 00000000..0e4fe4d7
--- /dev/null
+++ b/application/migrations/051_insert_custom_field_rows_to_settings_table.php
@@ -0,0 +1,65 @@
+<?php defined('BASEPATH') or exit('No direct script access allowed');
+
+/* ----------------------------------------------------------------------------
+ * Easy!Appointments - Online Appointment Scheduler
+ *
+ * @package     EasyAppointments
+ * @author      A.Tselegidis <alextselegidis@gmail.com>
+ * @copyright   Copyright (c) Alex Tselegidis
+ * @license     https://opensource.org/licenses/GPL-3.0 - GPLv3
+ * @link        https://easyappointments.org
+ * @since       v1.4.0
+ * ---------------------------------------------------------------------------- */
+
+class Migration_Insert_custom_field_rows_to_settings_table extends EA_Migration
+{
+    /**
+     * @var int
+     */
+    private const FIELD_NUMBER = 5;
+
+    private const SETTINGS = [
+        'display' => '0',
+        'require' => '0',
+        'label' => ''
+    ];
+
+    /**
+     * Upgrade method.
+     */
+    public function up()
+    {
+        for ($i = 1; $i <= self::FIELD_NUMBER; $i++) {
+            $field_name = 'custom_field_' . $i;
+
+            foreach (self::SETTINGS as $name => $default_value) {
+                $setting_name = $name . '_' . $field_name;
+
+                if (!$this->db->get_where('settings', ['name' => $setting_name])->num_rows()) {
+                    $this->db->insert('settings', [
+                        'name' => $setting_name,
+                        'value' => $default_value
+                    ]);
+                }
+            }
+        }
+    }
+
+    /**
+     * Downgrade method.
+     */
+    public function down()
+    {
+        for ($i = 1; $i >= self::FIELD_NUMBER; $i++) {
+            $field_name = 'custom_field_' . $i;
+
+            foreach (self::SETTINGS as $name => $default_value) {
+                $setting_name = $name . '_' . $field_name;
+
+                if ($this->db->get_where('settings', ['name' => $setting_name])->num_rows()) {
+                    $this->db->delete('settings', ['name' => $setting_name]);
+                }
+            }
+        }
+    }
+}
diff --git a/application/models/Customers_model.php b/application/models/Customers_model.php
index 1eaa9ab0..869a234c 100644
--- a/application/models/Customers_model.php
+++ b/application/models/Customers_model.php
@@ -18,13 +18,14 @@
  *
  * @package Models
  */
-class Customers_model extends EA_Model {
+class Customers_model extends EA_Model
+{
     /**
      * @var array
      */
     protected array $casts = [
         'id' => 'integer',
-        'id_roles' => 'integer',
+        'id_roles' => 'integer'
     ];
 
     /**
@@ -42,7 +43,12 @@ class Customers_model extends EA_Model {
         'zip' => 'zip_code',
         'timezone' => 'timezone',
         'language' => 'language',
-        'notes' => 'notes',
+        'customField1' => 'custom_field_1',
+        'customField2' => 'custom_field_2',
+        'customField3' => 'custom_field_3',
+        'customField4' => 'custom_field_4',
+        'customField5' => 'custom_field_5',
+        'notes' => 'notes'
     ];
 
     /**
@@ -58,17 +64,13 @@ class Customers_model extends EA_Model {
     {
         $this->validate($customer);
 
-        if ($this->exists($customer) && empty($customer['id']))
-        {
+        if ($this->exists($customer) && empty($customer['id'])) {
             $customer['id'] = $this->find_record_id($customer);
         }
 
-        if (empty($customer['id']))
-        {
+        if (empty($customer['id'])) {
             return $this->insert($customer);
-        }
-        else
-        {
+        } else {
             return $this->update($customer);
         }
     }
@@ -83,13 +85,13 @@ class Customers_model extends EA_Model {
     public function validate(array $customer)
     {
         // If a customer ID is provided then check whether the record really exists in the database.
-        if ( ! empty($customer['id']))
-        {
+        if (!empty($customer['id'])) {
             $count = $this->db->get_where('users', ['id' => $customer['id']])->num_rows();
 
-            if ( ! $count)
-            {
-                throw new InvalidArgumentException('The provided customer ID does not exist in the database: ' . $customer['id']);
+            if (!$count) {
+                throw new InvalidArgumentException(
+                    'The provided customer ID does not exist in the database: ' . $customer['id']
+                );
             }
         }
 
@@ -103,31 +105,27 @@ class Customers_model extends EA_Model {
         $require_zip_code = filter_var(setting('require_zip_code'), FILTER_VALIDATE_BOOLEAN);
 
         if (
-            (empty($customer['first_name']) && $require_first_name)
-            || (empty($customer['last_name']) && $require_last_name)
-            || (empty($customer['email']) && $require_email)
-            || (empty($customer['phone_number']) && $require_phone_number)
-            || (empty($customer['address']) && $require_address)
-            || (empty($customer['city']) && $require_city)
-            || (empty($customer['zip_code']) && $require_zip_code)
-        )
-        {
-            throw new InvalidArgumentException('Not all required fields are provided: ' . print_r($customer, TRUE));
+            (empty($customer['first_name']) && $require_first_name) ||
+            (empty($customer['last_name']) && $require_last_name) ||
+            (empty($customer['email']) && $require_email) ||
+            (empty($customer['phone_number']) && $require_phone_number) ||
+            (empty($customer['address']) && $require_address) ||
+            (empty($customer['city']) && $require_city) ||
+            (empty($customer['zip_code']) && $require_zip_code)
+        ) {
+            throw new InvalidArgumentException('Not all required fields are provided: ' . print_r($customer, true));
         }
 
-        if ( ! empty($customer['email']))
-        {
+        if (!empty($customer['email'])) {
             // Validate the email address.
-            if ( ! filter_var($customer['email'], FILTER_VALIDATE_EMAIL))
-            {
+            if (!filter_var($customer['email'], FILTER_VALIDATE_EMAIL)) {
                 throw new InvalidArgumentException('Invalid email address provided: ' . $customer['email']);
             }
 
             // Make sure the email address is unique.
-            $customer_id = $customer['id'] ?? NULL;
+            $customer_id = $customer['id'] ?? null;
 
-            $count = $this
-                ->db
+            $count = $this->db
                 ->select()
                 ->from('users')
                 ->join('roles', 'roles.id = users.id_roles', 'inner')
@@ -137,13 +135,123 @@ class Customers_model extends EA_Model {
                 ->get()
                 ->num_rows();
 
-            if ($count > 0)
-            {
-                throw new InvalidArgumentException('The provided email address is already in use, please use a different one.');
+            if ($count > 0) {
+                throw new InvalidArgumentException(
+                    'The provided email address is already in use, please use a different one.'
+                );
             }
         }
     }
 
+    /**
+     * Get all customers that match the provided criteria.
+     *
+     * @param array|string|null $where Where conditions.
+     * @param int|null $limit Record limit.
+     * @param int|null $offset Record offset.
+     * @param string|null $order_by Order by.
+     *
+     * @return array Returns an array of customers.
+     */
+    public function get(
+        array|string $where = null,
+        int $limit = null,
+        int $offset = null,
+        string $order_by = null
+    ): array {
+        $role_id = $this->get_customer_role_id();
+
+        if ($where !== null) {
+            $this->db->where($where);
+        }
+
+        if ($order_by !== null) {
+            $this->db->order_by($order_by);
+        }
+
+        $customers = $this->db->get_where('users', ['id_roles' => $role_id], $limit, $offset)->result_array();
+
+        foreach ($customers as &$customer) {
+            $this->cast($customer);
+        }
+
+        return $customers;
+    }
+
+    /**
+     * Get the customer role ID.
+     *
+     * @return int Returns the role ID.
+     */
+    public function get_customer_role_id(): int
+    {
+        $role = $this->db->get_where('roles', ['slug' => DB_SLUG_CUSTOMER])->row_array();
+
+        if (empty($role)) {
+            throw new RuntimeException('The customer role was not found in the database.');
+        }
+
+        return $role['id'];
+    }
+
+    /**
+     * Check if a particular customer record already exists in the database.
+     *
+     * @param array $customer Associative array with the customer data.
+     *
+     * @return bool Returns whether there is a record matching the provided one or not.
+     *
+     * @throws InvalidArgumentException
+     */
+    public function exists(array $customer): bool
+    {
+        if (empty($customer['email'])) {
+            return false;
+        }
+
+        $count = $this->db
+            ->select()
+            ->from('users')
+            ->join('roles', 'roles.id = users.id_roles', 'inner')
+            ->where('users.email', $customer['email'])
+            ->where('roles.slug', DB_SLUG_CUSTOMER)
+            ->get()
+            ->num_rows();
+
+        return $count > 0;
+    }
+
+    /**
+     * Find the record ID of a customer.
+     *
+     * @param array $customer Associative array with the customer data.
+     *
+     * @return int Returns the ID of the record that matches the provided argument.
+     *
+     * @throws InvalidArgumentException
+     */
+    public function find_record_id(array $customer): int
+    {
+        if (empty($customer['email'])) {
+            throw new InvalidArgumentException('The customer email was not provided: ' . print_r($customer, true));
+        }
+
+        $customer = $this->db
+            ->select('users.id')
+            ->from('users')
+            ->join('roles', 'roles.id = users.id_roles', 'inner')
+            ->where('users.email', $customer['email'])
+            ->where('roles.slug', DB_SLUG_CUSTOMER)
+            ->get()
+            ->row_array();
+
+        if (empty($customer)) {
+            throw new InvalidArgumentException('Could not find customer record id.');
+        }
+
+        return (int) $customer['id'];
+    }
+
     /**
      * Insert a new customer into the database.
      *
@@ -159,8 +267,7 @@ class Customers_model extends EA_Model {
         $customer['update_datetime'] = date('Y-m-d H:i:s');
         $customer['id_roles'] = $this->get_customer_role_id();
 
-        if ( ! $this->db->insert('users', $customer))
-        {
+        if (!$this->db->insert('users', $customer)) {
             throw new RuntimeException('Could not insert customer.');
         }
 
@@ -180,8 +287,7 @@ class Customers_model extends EA_Model {
     {
         $customer['update_datetime'] = date('Y-m-d H:i:s');
 
-        if ( ! $this->db->update('users', $customer, ['id' => $customer['id']]))
-        {
+        if (!$this->db->update('users', $customer, ['id' => $customer['id']])) {
             throw new RuntimeException('Could not update customer.');
         }
 
@@ -211,9 +317,10 @@ class Customers_model extends EA_Model {
     {
         $customer = $this->db->get_where('users', ['id' => $customer_id])->row_array();
 
-        if ( ! $customer)
-        {
-            throw new InvalidArgumentException('The provided customer ID was not found in the database: ' . $customer_id);
+        if (!$customer) {
+            throw new InvalidArgumentException(
+                'The provided customer ID was not found in the database: ' . $customer_id
+            );
         }
 
         $this->cast($customer);
@@ -233,22 +340,21 @@ class Customers_model extends EA_Model {
      */
     public function value(int $customer_id, string $field): mixed
     {
-        if (empty($field))
-        {
+        if (empty($field)) {
             throw new InvalidArgumentException('The field argument is cannot be empty.');
         }
 
-        if (empty($customer_id))
-        {
+        if (empty($customer_id)) {
             throw new InvalidArgumentException('The customer ID argument cannot be empty.');
         }
 
         // Check whether the customer exists.
         $query = $this->db->get_where('users', ['id' => $customer_id]);
 
-        if ( ! $query->num_rows())
-        {
-            throw new InvalidArgumentException('The provided customer ID was not found in the database: ' . $customer_id);
+        if (!$query->num_rows()) {
+            throw new InvalidArgumentException(
+                'The provided customer ID was not found in the database: ' . $customer_id
+            );
         }
 
         // Check if the required field is part of the customer data.
@@ -256,128 +362,13 @@ class Customers_model extends EA_Model {
 
         $this->cast($customer);
 
-        if ( ! array_key_exists($field, $customer))
-        {
+        if (!array_key_exists($field, $customer)) {
             throw new InvalidArgumentException('The requested field was not found in the customer data: ' . $field);
         }
 
         return $customer[$field];
     }
 
-    /**
-     * Get all customers that match the provided criteria.
-     *
-     * @param array|string|null $where Where conditions.
-     * @param int|null $limit Record limit.
-     * @param int|null $offset Record offset.
-     * @param string|null $order_by Order by.
-     *
-     * @return array Returns an array of customers.
-     */
-    public function get(array|string $where = NULL, int $limit = NULL, int $offset = NULL, string $order_by = NULL): array
-    {
-        $role_id = $this->get_customer_role_id();
-
-        if ($where !== NULL)
-        {
-            $this->db->where($where);
-        }
-
-        if ($order_by !== NULL)
-        {
-            $this->db->order_by($order_by);
-        }
-
-        $customers = $this->db->get_where('users', ['id_roles' => $role_id], $limit, $offset)->result_array();
-
-        foreach ($customers as &$customer)
-        {
-            $this->cast($customer);
-        }
-
-        return $customers;
-    }
-
-    /**
-     * Get the customer role ID.
-     *
-     * @return int Returns the role ID.
-     */
-    public function get_customer_role_id(): int
-    {
-        $role = $this->db->get_where('roles', ['slug' => DB_SLUG_CUSTOMER])->row_array();
-
-        if (empty($role))
-        {
-            throw new RuntimeException('The customer role was not found in the database.');
-        }
-
-        return $role['id'];
-    }
-
-    /**
-     * Check if a particular customer record already exists in the database.
-     *
-     * @param array $customer Associative array with the customer data.
-     *
-     * @return bool Returns whether there is a record matching the provided one or not.
-     *
-     * @throws InvalidArgumentException
-     */
-    public function exists(array $customer): bool
-    {
-        if (empty($customer['email']))
-        {
-            return FALSE;
-        }
-
-        $count = $this
-            ->db
-            ->select()
-            ->from('users')
-            ->join('roles', 'roles.id = users.id_roles', 'inner')
-            ->where('users.email', $customer['email'])
-            ->where('roles.slug', DB_SLUG_CUSTOMER)
-            ->get()
-            ->num_rows();
-
-        return $count > 0;
-    }
-
-    /**
-     * Find the record ID of a customer.
-     *
-     * @param array $customer Associative array with the customer data.
-     *
-     * @return int Returns the ID of the record that matches the provided argument.
-     *
-     * @throws InvalidArgumentException
-     */
-    public function find_record_id(array $customer): int
-    {
-        if (empty($customer['email']))
-        {
-            throw new InvalidArgumentException('The customer email was not provided: ' . print_r($customer, TRUE));
-        }
-
-        $customer = $this
-            ->db
-            ->select('users.id')
-            ->from('users')
-            ->join('roles', 'roles.id = users.id_roles', 'inner')
-            ->where('users.email', $customer['email'])
-            ->where('roles.slug', DB_SLUG_CUSTOMER)
-            ->get()
-            ->row_array();
-
-        if (empty($customer))
-        {
-            throw new InvalidArgumentException('Could not find customer record id.');
-        }
-
-        return (int)$customer['id'];
-    }
-
     /**
      * Get the query builder interface, configured for use with the users (customer-filtered) table.
      *
@@ -400,12 +391,11 @@ class Customers_model extends EA_Model {
      *
      * @return array Returns an array of customers.
      */
-    public function search(string $keyword, int $limit = NULL, int $offset = NULL, string $order_by = NULL): array
+    public function search(string $keyword, int $limit = null, int $offset = null, string $order_by = null): array
     {
         $role_id = $this->get_customer_role_id();
 
-        $customers = $this
-            ->db
+        $customers = $this->db
             ->select()
             ->from('users')
             ->where('id_roles', $role_id)
@@ -428,8 +418,7 @@ class Customers_model extends EA_Model {
             ->get()
             ->result_array();
 
-        foreach ($customers as &$customer)
-        {
+        foreach ($customers as &$customer) {
             $this->cast($customer);
         }
 
@@ -457,7 +446,7 @@ class Customers_model extends EA_Model {
     public function api_encode(array &$customer)
     {
         $encoded_resource = [
-            'id' => array_key_exists('id', $customer) ? (int)$customer['id'] : NULL,
+            'id' => array_key_exists('id', $customer) ? (int) $customer['id'] : null,
             'firstName' => $customer['first_name'],
             'lastName' => $customer['last_name'],
             'email' => $customer['email'],
@@ -467,6 +456,11 @@ class Customers_model extends EA_Model {
             'zip' => $customer['zip_code'],
             'notes' => $customer['notes'],
             'timezone' => $customer['timezone'],
+            'customField1' => $customer['custom_field_1'],
+            'customField2' => $customer['custom_field_2'],
+            'customField3' => $customer['custom_field_3'],
+            'customField4' => $customer['custom_field_4'],
+            'customField5' => $customer['custom_field_5']
         ];
 
         $customer = $encoded_resource;
@@ -478,52 +472,67 @@ class Customers_model extends EA_Model {
      * @param array $customer API resource.
      * @param array|null $base Base customer data to be overwritten with the provided values (useful for updates).
      */
-    public function api_decode(array &$customer, array $base = NULL)
+    public function api_decode(array &$customer, array $base = null)
     {
         $decoded_resource = $base ?: [];
 
-        if (array_key_exists('id', $customer))
-        {
+        if (array_key_exists('id', $customer)) {
             $decoded_resource['id'] = $customer['id'];
         }
 
-        if (array_key_exists('firstName', $customer))
-        {
+        if (array_key_exists('firstName', $customer)) {
             $decoded_resource['first_name'] = $customer['firstName'];
         }
 
-        if (array_key_exists('lastName', $customer))
-        {
+        if (array_key_exists('lastName', $customer)) {
             $decoded_resource['last_name'] = $customer['lastName'];
         }
 
-        if (array_key_exists('email', $customer))
-        {
+        if (array_key_exists('email', $customer)) {
             $decoded_resource['email'] = $customer['email'];
         }
 
-        if (array_key_exists('phone', $customer))
-        {
+        if (array_key_exists('phone', $customer)) {
             $decoded_resource['phone_number'] = $customer['phone'];
         }
 
-        if (array_key_exists('address', $customer))
-        {
+        if (array_key_exists('address', $customer)) {
             $decoded_resource['address'] = $customer['address'];
         }
 
-        if (array_key_exists('city', $customer))
-        {
+        if (array_key_exists('city', $customer)) {
             $decoded_resource['city'] = $customer['city'];
         }
 
-        if (array_key_exists('zip', $customer))
-        {
+        if (array_key_exists('zip', $customer)) {
             $decoded_resource['zip_code'] = $customer['zip'];
         }
 
-        if (array_key_exists('notes', $customer))
-        {
+        if (array_key_exists('language', $customer)) {
+            $decoded_resource['language'] = $customer['language'];
+        }
+
+        if (array_key_exists('customField1', $customer)) {
+            $decoded_resource['custom_field_1'] = $customer['customField1'];
+        }
+
+        if (array_key_exists('customField2', $customer)) {
+            $decoded_resource['custom_field_2'] = $customer['customField2'];
+        }
+
+        if (array_key_exists('customField3', $customer)) {
+            $decoded_resource['custom_field_3'] = $customer['customField3'];
+        }
+
+        if (array_key_exists('customField4', $customer)) {
+            $decoded_resource['custom_field_4'] = $customer['customField4'];
+        }
+
+        if (array_key_exists('customField5', $customer)) {
+            $decoded_resource['custom_field_5'] = $customer['customField5'];
+        }
+
+        if (array_key_exists('notes', $customer)) {
             $decoded_resource['notes'] = $customer['notes'];
         }
 
diff --git a/application/views/components/appointments_modal.php b/application/views/components/appointments_modal.php
index c6df1f7e..3c333e2e 100644
--- a/application/views/components/appointments_modal.php
+++ b/application/views/components/appointments_modal.php
@@ -43,27 +43,21 @@
                                         <?php
                                         // Group services by category, only if there is at least one service
                                         // with a parent category.
-                                        $has_category = FALSE;
+                                        $has_category = false;
 
-                                        foreach ($available_services as $service)
-                                        {
-                                            if ( ! empty($service['category_id']))
-                                            {
-                                                $has_category = TRUE;
+                                        foreach ($available_services as $service) {
+                                            if (!empty($service['category_id'])) {
+                                                $has_category = true;
                                                 break;
                                             }
                                         }
 
-                                        if ($has_category)
-                                        {
+                                        if ($has_category) {
                                             $grouped_services = [];
 
-                                            foreach ($available_services as $service)
-                                            {
-                                                if ( ! empty($service['category_id']))
-                                                {
-                                                    if ( ! isset($grouped_services[$service['category_name']]))
-                                                    {
+                                            foreach ($available_services as $service) {
+                                                if (!empty($service['category_id'])) {
+                                                    if (!isset($grouped_services[$service['category_name']])) {
                                                         $grouped_services[$service['category_name']] = [];
                                                     }
 
@@ -75,40 +69,39 @@
                                             // another iteration only for the uncategorized services.
                                             $grouped_services['uncategorized'] = [];
 
-                                            foreach ($available_services as $service)
-                                            {
-                                                if ($service['category_id'] == NULL)
-                                                {
+                                            foreach ($available_services as $service) {
+                                                if ($service['category_id'] == null) {
                                                     $grouped_services['uncategorized'][] = $service;
                                                 }
                                             }
 
-                                            foreach ($grouped_services as $key => $group)
-                                            {
-                                                $group_label = $key !== 'uncategorized'
-                                                    ? e($group[0]['category_name'])
-                                                    : 'Uncategorized';
+                                            foreach ($grouped_services as $key => $group) {
+                                                $group_label =
+                                                    $key !== 'uncategorized'
+                                                        ? e($group[0]['category_name'])
+                                                        : 'Uncategorized';
 
-                                                if (count($group) > 0)
-                                                {
+                                                if (count($group) > 0) {
                                                     echo '<optgroup label="' . $group_label . '">';
 
-                                                    foreach ($group as $service)
-                                                    {
-                                                        echo '<option value="' . $service['id'] . '">'
-                                                            . e($service['name']) . '</option>';
+                                                    foreach ($group as $service) {
+                                                        echo '<option value="' .
+                                                            $service['id'] .
+                                                            '">' .
+                                                            e($service['name']) .
+                                                            '</option>';
                                                     }
 
                                                     echo '</optgroup>';
                                                 }
                                             }
-                                        }
-                                        else
-                                        {
-                                            foreach ($available_services as $service)
-                                            {
-                                                echo '<option value="' . $service['id'] . '">'
-                                                    . e($service['name']) . '</option>';
+                                        } else {
+                                            foreach ($available_services as $service) {
+                                                echo '<option value="' .
+                                                    $service['id'] .
+                                                    '">' .
+                                                    e($service['name']) .
+                                                    '</option>';
                                             }
                                         }
                                         ?>
@@ -124,7 +117,7 @@
                                 </div>
 
                                 <div class="mb-3">
-                                    <?php component('color_selection', ['attributes' => 'id="appointment-color"']) ?>
+                                    <?php component('color_selection', ['attributes' => 'id="appointment-color"']); ?>
                                 </div>
 
                                 <div class="mb-3">
@@ -143,7 +136,7 @@
                                             <option value="<?= e($appointment_status_option) ?>">
                                                 <?= e($appointment_status_option) ?>
                                             </option>
-                                        <?php endforeach ?>
+                                        <?php endforeach; ?>
                                     </select>
                                 </div>
                             </div>
@@ -228,7 +221,7 @@
                                         <?= lang('first_name') ?>
                                         <?php if ($require_first_name): ?>
                                             <span class="text-danger">*</span>
-                                        <?php endif ?>
+                                        <?php endif; ?>
                                     </label>
                                     <input type="text" id="first-name"
                                            class="<?= $require_first_name ? 'required' : '' ?> form-control"
@@ -240,7 +233,7 @@
                                         <?= lang('last_name') ?>
                                         <?php if ($require_last_name): ?>
                                             <span class="text-danger">*</span>
-                                        <?php endif ?>
+                                        <?php endif; ?>
                                     </label>
                                     <input type="text" id="last-name"
                                            class="<?= $require_last_name ? 'required' : '' ?> form-control"
@@ -252,7 +245,7 @@
                                         <?= lang('email') ?>
                                         <?php if ($require_email): ?>
                                             <span class="text-danger">*</span>
-                                        <?php endif ?>
+                                        <?php endif; ?>
                                     </label>
                                     <input type="text" id="email"
                                            class="<?= $require_email ? 'required' : '' ?> form-control"
@@ -264,7 +257,7 @@
                                         <?= lang('phone_number') ?>
                                         <?php if ($require_phone_number): ?>
                                             <span class="text-danger">*</span>
-                                        <?php endif ?>
+                                        <?php endif; ?>
                                     </label>
                                     <input type="text" id="phone-number" maxlength="60"
                                            class="<?= $require_phone_number ? 'required' : '' ?> form-control"/>
@@ -280,7 +273,7 @@
                                             <option value="<?= $available_language ?>">
                                                 <?= ucfirst($available_language) ?>
                                             </option>
-                                        <?php endforeach ?>
+                                        <?php endforeach; ?>
                                     </select>
                                 </div>
                             </div>
@@ -290,7 +283,7 @@
                                         <?= lang('address') ?>
                                         <?php if ($require_address): ?>
                                             <span class="text-danger">*</span>
-                                        <?php endif ?>
+                                        <?php endif; ?>
                                     </label>
                                     <input type="text" id="address"
                                            class="<?= $require_address ? 'required' : '' ?> form-control"
@@ -302,7 +295,7 @@
                                         <?= lang('city') ?>
                                         <?php if ($require_city): ?>
                                             <span class="text-danger">*</span>
-                                        <?php endif ?>
+                                        <?php endif; ?>
                                     </label>
                                     <input type="text" id="city"
                                            class="<?= $require_city ? 'required' : '' ?> form-control"
@@ -314,7 +307,7 @@
                                         <?= lang('zip_code') ?>
                                         <?php if ($require_zip_code): ?>
                                             <span class="text-danger">*</span>
-                                        <?php endif ?>
+                                        <?php endif; ?>
                                     </label>
                                     <input type="text" id="zip-code"
                                            class="<?= $require_zip_code ? 'required' : '' ?> form-control"
@@ -329,7 +322,7 @@
                                     <?php component('timezone_dropdown', [
                                         'attributes' => 'id="timezone" class="form-control required"',
                                         'grouped_timezones' => vars('grouped_timezones')
-                                    ]) ?>
+                                    ]); ?>
                                 </div>
 
                                 <div class="mb-3">
@@ -337,12 +330,16 @@
                                         <?= lang('notes') ?>
                                         <?php if ($require_notes): ?>
                                             <span class="text-danger">*</span>
-                                        <?php endif ?>
+                                        <?php endif; ?>
                                     </label>
                                     <textarea id="customer-notes" rows="2"
                                               class="<?= $require_notes ? 'required' : '' ?> form-control"></textarea>
                                 </div>
                             </div>
+
+                            <div class="mb-3">
+                                <?php component('custom_fields'); ?>
+                            </div>
                         </div>
                     </fieldset>
                 </form>
@@ -361,8 +358,8 @@
     </div>
 </div>
 
-<?php section('scripts') ?>
+<?php section('scripts'); ?>
 
 <script src="<?= asset_url('assets/js/components/appointments_modal.js') ?>"></script>
 
-<?php end_section('scripts') ?>
+<?php end_section('scripts'); ?>
diff --git a/application/views/components/booking_info_step.php b/application/views/components/booking_info_step.php
index 89c337c3..03a966d4 100644
--- a/application/views/components/booking_info_step.php
+++ b/application/views/components/booking_info_step.php
@@ -131,6 +131,10 @@
                     </div>
                 <?php endif; ?>
             </div>
+
+            <div class="mb-3">
+                <?php component('custom_fields'); ?>
+            </div>
         </div>
     </div>
 
diff --git a/application/views/components/custom_fields.php b/application/views/components/custom_fields.php
new file mode 100644
index 00000000..809f4e7e
--- /dev/null
+++ b/application/views/components/custom_fields.php
@@ -0,0 +1,24 @@
+<?php
+/**
+ * Local variables.
+ *
+ * @var bool $disabled (false)
+ */
+
+$disabled = $disabled ?? false; ?>
+
+<?php for ($i = 1; $i <= 5; $i++): ?>
+    <?php if (setting('display_custom_field_' . $i)): ?>
+        <div class="mb-3">
+            <label for="custom-field-<?= $i ?>" class="form-label">
+                <?= setting('label_custom_field_' . $i) ?: lang('custom_field') . ' #' . $i ?>
+                <?php if (vars('require_custom_field_' . $i)): ?>
+                    <span class="text-danger" hidden>*</span>
+                <?php endif; ?>
+            </label>
+            <input type="text" id="custom-field-<?= $i ?>"
+                   class="<?= vars('require_custom_field_' . $i) ? 'required' : '' ?> form-control"
+                   maxlength="120" <?= $disabled ? 'disabled' : '' ?>/>
+        </div>
+    <?php endif; ?>
+<?php endfor; ?>
diff --git a/application/views/pages/booking_settings.php b/application/views/pages/booking_settings.php
index c2315a24..06f0a30e 100755
--- a/application/views/pages/booking_settings.php
+++ b/application/views/pages/booking_settings.php
@@ -246,6 +246,50 @@
                             </div>
                         </div>
 
+                        <h5 class="text-black-50 mb-3 fw-light">
+                            <?= lang('custom_fields') ?>
+                        </h5>
+
+                        <div class="row mb-5 fields-row">
+                            <?php for ($i = 1; $i <= 5; $i++): ?>
+                                <div class="col-sm-6">
+                                    <div class="form-group mb-5">
+                                        <label for="first-name" class="form-label">
+                                            <?= lang('custom_field') ?> #<?= $i ?>
+                                            <span class="text-danger">*</span>
+                                        </label>
+
+                                        <input type="text" id="custom-field-<?= $i ?>" class="form-control mb-2"
+                                               placeholder="<?= lang('label') ?>"
+                                               data-field="label_custom_field_<?= $i ?>"
+                                               aria-label="label"
+                                        />
+
+                                        <div class="d-flex">
+                                            <div class="form-check form-switch me-4">
+                                                <input class="form-check-input display-switch" type="checkbox"
+                                                       id="display-custom-field-<?= $i ?>"
+                                                       data-field="display_custom_field_<?= $i ?>">
+                                                <label class="form-check-label" for="display-custom-field-<?= $i ?>">
+                                                    <?= lang('display') ?>
+                                                </label>
+                                            </div>
+
+                                            <div class="form-check form-switch">
+                                                <input class="form-check-input require-switch" type="checkbox"
+                                                       id="require-custom-field-<?= $i ?>"
+                                                       data-field="require_custom_field_<?= $i ?>">
+                                                <label class="form-check-label" for="require-custom-field-<?= $i ?>">
+                                                    <?= lang('require') ?>
+                                                </label>
+                                            </div>
+                                        </div>
+                                    </div>
+                                </div>
+                            <?php endfor; ?>
+                        </div>
+
+
                         <h5 class="text-black-50 mb-3 fw-light">
                             <?= lang('options') ?>
                         </h5>
diff --git a/application/views/pages/customers.php b/application/views/pages/customers.php
index dbe7366d..69c59f2d 100755
--- a/application/views/pages/customers.php
+++ b/application/views/pages/customers.php
@@ -181,7 +181,9 @@
                         ]); ?>
                     </div>
 
-                    <?php component('auxiliary_fields'); ?>
+                    <?php component('custom_fields', [
+                        'disabled' => true
+                    ]); ?>
 
                     <div class="mb-3">
                         <label class="form-label" for="notes">
diff --git a/assets/js/components/appointments_modal.js b/assets/js/components/appointments_modal.js
index 053661cf..cc91c8bf 100755
--- a/assets/js/components/appointments_modal.js
+++ b/assets/js/components/appointments_modal.js
@@ -46,6 +46,11 @@ App.Components.AppointmentsModal = (function () {
     const $insertAppointment = $('#insert-appointment');
     const $existingCustomersList = $('#existing-customers-list');
     const $newCustomer = $('#new-customer');
+    const $customField1 = $('#custom-field-1');
+    const $customField2 = $('#custom-field-2');
+    const $customField3 = $('#custom-field-3');
+    const $customField4 = $('#custom-field-4');
+    const $customField5 = $('#custom-field-5');
 
     /**
      * Update the displayed timezone.
@@ -110,7 +115,12 @@ App.Components.AppointmentsModal = (function () {
                 zip_code: $zipCode.val(),
                 language: $language.val(),
                 timezone: $timezone.val(),
-                notes: $customerNotes.val()
+                notes: $customerNotes.val(),
+                custom_field_1: $customField1.val(),
+                custom_field_2: $customField2.val(),
+                custom_field_3: $customField3.val(),
+                custom_field_4: $customField4.val(),
+                custom_field_5: $customField5.val()
             };
 
             if ($customerId.val() !== '') {
@@ -196,7 +206,7 @@ App.Components.AppointmentsModal = (function () {
 
             $startDatetime[0]._flatpickr.setDate(startMoment.toDate());
             $endDatetime[0]._flatpickr.setDate(startMoment.add(duration, 'minutes').toDate());
-            
+
             // Display modal form.
             $appointmentsModal.find('.modal-header h3').text(lang('new_appointment_title'));
 
@@ -217,7 +227,8 @@ App.Components.AppointmentsModal = (function () {
                 vars('customers').forEach((customer) => {
                     $('<div/>', {
                         'data-id': customer.id,
-                        'text': (customer.first_name || '[No First Name]') + ' ' + (customer.last_name || '[No Last Name]')
+                        'text':
+                            (customer.first_name || '[No First Name]') + ' ' + (customer.last_name || '[No Last Name]')
                     }).appendTo($existingCustomersList);
                 });
             } else {
@@ -249,6 +260,11 @@ App.Components.AppointmentsModal = (function () {
                 $language.val(customer.language);
                 $timezone.val(customer.timezone);
                 $customerNotes.val(customer.notes);
+                $customField1.val(customer.custom_field_1);
+                $customField2.val(customer.custom_field_2);
+                $customField3.val(customer.custom_field_3);
+                $customField4.val(customer.custom_field_4);
+                $customField5.val(customer.custom_field_5);
             }
 
             $selectCustomer.trigger('click'); // Hide the list.
@@ -278,7 +294,10 @@ App.Components.AppointmentsModal = (function () {
                         response.forEach((customer) => {
                             $('<div/>', {
                                 'data-id': customer.id,
-                                'text': (customer.first_name || '[No First Name]') + ' ' + (customer.last_name || '[No Last Name]')
+                                'text':
+                                    (customer.first_name || '[No First Name]') +
+                                    ' ' +
+                                    (customer.last_name || '[No Last Name]')
                             }).appendTo($existingCustomersList);
 
                             // Verify if this customer is on the old customer list.
@@ -309,7 +328,10 @@ App.Components.AppointmentsModal = (function () {
                             ) {
                                 $('<div/>', {
                                     'data-id': customer.id,
-                                    'text': (customer.first_name || '[No First Name]') + ' ' + (customer.last_name || '[No Last Name]')
+                                    'text':
+                                        (customer.first_name || '[No First Name]') +
+                                        ' ' +
+                                        (customer.last_name || '[No Last Name]')
                                 }).appendTo($existingCustomersList);
                             }
                         });
@@ -328,8 +350,8 @@ App.Components.AppointmentsModal = (function () {
          */
         $selectService.on('change', () => {
             const serviceId = $selectService.val();
-            
-            const providerId = $selectProvider.val(); 
+
+            const providerId = $selectProvider.val();
 
             $selectProvider.empty();
 
@@ -341,7 +363,7 @@ App.Components.AppointmentsModal = (function () {
             const duration = service ? service.duration : 60;
 
             const start = $startDatetime[0]._flatpickr.selectedDates[0];
-            $endDatetime[0]._flatpickr.setDate( new Date(start.getTime() + duration * 60000));
+            $endDatetime[0]._flatpickr.setDate(new Date(start.getTime() + duration * 60000));
 
             // Update the providers select box.
 
@@ -366,7 +388,7 @@ App.Components.AppointmentsModal = (function () {
                         $selectProvider.append(new Option(provider.first_name + ' ' + provider.last_name, provider.id));
                     }
                 });
-                
+
                 if ($selectProvider.find(`option[value="${providerId}"]`).length) {
                     $selectProvider.val(providerId);
                 }
@@ -395,6 +417,11 @@ App.Components.AppointmentsModal = (function () {
             $language.val('english');
             $timezone.val('UTC');
             $customerNotes.val('');
+            $customField1.val('');
+            $customField2.val('');
+            $customField3.val('');
+            $customField4.val('');
+            $customField5.val('');
         });
     }
 
@@ -464,14 +491,14 @@ App.Components.AppointmentsModal = (function () {
                 );
 
                 const start = $startDatetime[0]._flatpickr.selectedDates[0];
-                $endDatetime[0]._flatpickr.setDate( new Date(start.getTime() + service.duration * 60000));
+                $endDatetime[0]._flatpickr.setDate(new Date(start.getTime() + service.duration * 60000));
             }
         });
 
-        $startDatetime[0]._flatpickr.setDate( startDatetime);
+        $startDatetime[0]._flatpickr.setDate(startDatetime);
 
         App.Utils.UI.initializeDatetimepicker($endDatetime);
-        $endDatetime[0]._flatpickr.setDate( endDatetime);
+        $endDatetime[0]._flatpickr.setDate(endDatetime);
     }
 
     /**
@@ -502,7 +529,10 @@ App.Components.AppointmentsModal = (function () {
             }
 
             // Check email address.
-            if ($appointmentsModal.find('#email').val() && !App.Utils.Validation.email($appointmentsModal.find('#email').val())) {
+            if (
+                $appointmentsModal.find('#email').val() &&
+                !App.Utils.Validation.email($appointmentsModal.find('#email').val())
+            ) {
                 $appointmentsModal.find('#email').addClass('is-invalid');
                 throw new Error(lang('invalid_email'));
             }
diff --git a/assets/js/pages/customers.js b/assets/js/pages/customers.js
index 8fd409c6..e8935095 100644
--- a/assets/js/pages/customers.js
+++ b/assets/js/pages/customers.js
@@ -27,9 +27,15 @@ App.Pages.Customers = (function () {
     const $zipCode = $('#zip-code');
     const $timezone = $('#timezone');
     const $language = $('#language');
+    const $customField1 = $('#custom-field-1');
+    const $customField2 = $('#custom-field-2');
+    const $customField3 = $('#custom-field-3');
+    const $customField4 = $('#custom-field-4');
+    const $customField5 = $('#custom-field-5');
     const $notes = $('#notes');
     const $formMessage = $('#form-message');
     const $customerAppointments = $('#customer-appointments');
+
     let filterResults = {};
     let filterLimit = 20;
 
@@ -124,7 +130,12 @@ App.Pages.Customers = (function () {
                 zip_code: $zipCode.val(),
                 notes: $notes.val(),
                 timezone: $timezone.val(),
-                language: $language.val() || 'english'
+                language: $language.val() || 'english',
+                custom_field_1: $customField1.val(),
+                custom_field_2: $customField2.val(),
+                custom_field_3: $customField3.val(),
+                custom_field_4: $customField4.val(),
+                custom_field_5: $customField5.val()
             };
 
             if ($id.val()) {
@@ -276,6 +287,11 @@ App.Pages.Customers = (function () {
         $notes.val(customer.notes);
         $timezone.val(customer.timezone);
         $language.val(customer.language || 'english');
+        $customField1.val(customer.custom_field_1);
+        $customField2.val(customer.custom_field_2);
+        $customField3.val(customer.custom_field_3);
+        $customField4.val(customer.custom_field_4);
+        $customField5.val(customer.custom_field_5);
 
         $customerAppointments.empty();
 
diff --git a/assets/js/utils/calendar_default_view.js b/assets/js/utils/calendar_default_view.js
index f305a27f..c389a715 100755
--- a/assets/js/utils/calendar_default_view.js
+++ b/assets/js/utils/calendar_default_view.js
@@ -158,6 +158,11 @@ App.Utils.CalendarDefaultView = (function () {
                 $appointmentsModal.find('#appointment-status').val(appointment.status);
                 $appointmentsModal.find('#appointment-notes').val(appointment.notes);
                 $appointmentsModal.find('#customer-notes').val(customer.notes);
+                $appointmentsModal.find('#custom-field-1').val(customer.custom_field_1);
+                $appointmentsModal.find('#custom-field-2').val(customer.custom_field_2);
+                $appointmentsModal.find('#custom-field-3').val(customer.custom_field_3);
+                $appointmentsModal.find('#custom-field-4').val(customer.custom_field_4);
+                $appointmentsModal.find('#custom-field-5').val(customer.custom_field_5);
 
                 App.Components.ColorSelection.setColor(
                     $appointmentsModal.find('#appointment-color'),
@@ -287,7 +292,10 @@ App.Utils.CalendarDefaultView = (function () {
          */
         $selectFilterItem.on('change', () => {
             // If current value is service, then the sync buttons must be disabled.
-            if ($selectFilterItem.find('option:selected').attr('type') === FILTER_TYPE_SERVICE || $selectFilterItem.val() === 'all') {
+            if (
+                $selectFilterItem.find('option:selected').attr('type') === FILTER_TYPE_SERVICE ||
+                $selectFilterItem.val() === 'all'
+            ) {
                 $('#google-sync, #enable-sync, #insert-appointment, #insert-dropdown').prop('disabled', true);
                 fullCalendar.setOption('selectable', false);
                 fullCalendar.setOption('editable', false);
@@ -317,7 +325,9 @@ App.Utils.CalendarDefaultView = (function () {
                     $('#google-sync').prop('disabled', true);
                 }
 
-                $('#insert-working-plan-exception').toggle(providerId !== App.Utils.CalendarDefaultView.FILTER_TYPE_ALL);
+                $('#insert-working-plan-exception').toggle(
+                    providerId !== App.Utils.CalendarDefaultView.FILTER_TYPE_ALL
+                );
             }
 
             $reloadAppointments.trigger('click');
@@ -382,10 +392,10 @@ App.Utils.CalendarDefaultView = (function () {
                 $target.hasClass('fc-custom') && vars('privileges').appointments.edit === true ? '' : 'd-none';
             displayDelete =
                 $target.hasClass('fc-custom') && vars('privileges').appointments.delete === true ? 'me-2' : 'd-none'; // Same value at the time.
-            
+
             let startDateTimeObject = info.event.start;
             let endDateTimeObject = info.event.end || info.event.start;
-            
+
             if (info.event.extendedProps.data) {
                 startDateTimeObject = new Date(info.event.extendedProps.data.start_datetime);
                 endDateTimeObject = new Date(info.event.extendedProps.data.end_datetime);
@@ -496,11 +506,14 @@ App.Utils.CalendarDefaultView = (function () {
                         'text': lang('start')
                     }),
                     $('<span/>', {
-                        'text': startTime ? App.Utils.Date.format(`${date} ${startTime}`,
-                            vars('date_format'),
-                            vars('time_format'),
-                            true
-                        ) : '-'
+                        'text': startTime
+                            ? App.Utils.Date.format(
+                                  `${date} ${startTime}`,
+                                  vars('date_format'),
+                                  vars('time_format'),
+                                  true
+                              )
+                            : '-'
                     }),
                     $('<br/>'),
 
@@ -509,11 +522,14 @@ App.Utils.CalendarDefaultView = (function () {
                         'text': lang('end')
                     }),
                     $('<span/>', {
-                        'text': endTime ? App.Utils.Date.format(`${date} ${endTime}`,
-                            vars('date_format'),
-                            vars('time_format'),
-                            true
-                        ) : '-'
+                        'text': endTime
+                            ? App.Utils.Date.format(
+                                  `${date} ${endTime}`,
+                                  vars('date_format'),
+                                  vars('time_format'),
+                                  true
+                              )
+                            : '-'
                     }),
                     $('<br/>'),
 
@@ -626,7 +642,7 @@ App.Utils.CalendarDefaultView = (function () {
                         'text': lang('status')
                     }),
                     $('<span/>', {
-                        'text': info.event.extendedProps.data.status || '-',
+                        'text': info.event.extendedProps.data.status || '-'
                     }),
                     $('<br/>'),
 
@@ -1025,8 +1041,7 @@ App.Utils.CalendarDefaultView = (function () {
             return;
         }
 
-        const isProviderDisplayed =
-            $selectFilterItem.find('option:selected').attr('type') === FILTER_TYPE_PROVIDER;
+        const isProviderDisplayed = $selectFilterItem.find('option:selected').attr('type') === FILTER_TYPE_PROVIDER;
 
         const buttons = [
             {
@@ -1059,8 +1074,7 @@ App.Utils.CalendarDefaultView = (function () {
 
                     if (isProviderDisplayed) {
                         const provider = vars('available_providers').find(
-                            (availableProvider) =>
-                                Number(availableProvider.id) === Number($selectFilterItem.val())
+                            (availableProvider) => Number(availableProvider.id) === Number($selectFilterItem.val())
                         );
 
                         if (provider) {
@@ -1090,8 +1104,7 @@ App.Utils.CalendarDefaultView = (function () {
                         $appointmentsModal.find('#select-provider').trigger('change');
                     } else {
                         service = vars('available_services').find(
-                            (availableService) =>
-                                Number(availableService.id) === Number($selectFilterItem.val())
+                            (availableService) => Number(availableService.id) === Number($selectFilterItem.val())
                         );
 
                         if (service) {
@@ -1182,9 +1195,7 @@ App.Utils.CalendarDefaultView = (function () {
 
                 // Add appointments to calendar.
                 response.appointments.forEach((appointment) => {
-                    const title = [
-                        appointment.service.name
-                    ];
+                    const title = [appointment.service.name];
 
                     const customerInfo = [];
 
@@ -1236,7 +1247,7 @@ App.Utils.CalendarDefaultView = (function () {
                     calendarEventSource.push(unavailabilityEvent);
                 });
 
-                response.blocked_periods.forEach(blockedPeriod => {
+                response.blocked_periods.forEach((blockedPeriod) => {
                     const blockedPeriodEvent = {
                         title: blockedPeriod.name,
                         start: moment(blockedPeriod.start_datetime).toDate(),
@@ -1263,7 +1274,9 @@ App.Utils.CalendarDefaultView = (function () {
                     (availableProvider) => Number(availableProvider.id) === Number(recordId)
                 );
 
-                const workingPlan = JSON.parse(provider ? provider.settings.working_plan : vars('company_working_plan'));
+                const workingPlan = JSON.parse(
+                    provider ? provider.settings.working_plan : vars('company_working_plan')
+                );
                 const workingPlanExceptions = JSON.parse(provider ? provider.settings.working_plan_exceptions : '{}');
                 let unavailabilityEvent;
                 let breakStart;
@@ -1304,9 +1317,7 @@ App.Utils.CalendarDefaultView = (function () {
                         workingPlanExceptionEvent = {
                             title: lang('working_plan_exception'),
                             start: moment(workingPlanExceptionStart, 'YYYY-MM-DD HH:mm', true).toDate(),
-                            end: moment(workingPlanExceptionEnd, 'YYYY-MM-DD HH:mm', true)
-                                .add(1, 'day')
-                                .toDate(),
+                            end: moment(workingPlanExceptionEnd, 'YYYY-MM-DD HH:mm', true).add(1, 'day').toDate(),
                             allDay: true,
                             color: '#879DB4',
                             editable: false,
@@ -1352,10 +1363,7 @@ App.Utils.CalendarDefaultView = (function () {
                             title: lang('not_working'),
                             start: calendarDate.clone().toDate(),
                             end: moment(
-                                calendarDate.format('YYYY-MM-DD') +
-                                ' ' +
-                                sortedWorkingPlan[weekdayName].start +
-                                ':00'
+                                calendarDate.format('YYYY-MM-DD') + ' ' + sortedWorkingPlan[weekdayName].start + ':00'
                             ).toDate(),
                             allDay: false,
                             color: '#BEBEBE',
@@ -1376,10 +1384,7 @@ App.Utils.CalendarDefaultView = (function () {
                         unavailabilityEvent = {
                             title: lang('not_working'),
                             start: moment(
-                                calendarDate.format('YYYY-MM-DD') +
-                                ' ' +
-                                sortedWorkingPlan[weekdayName].end +
-                                ':00'
+                                calendarDate.format('YYYY-MM-DD') + ' ' + sortedWorkingPlan[weekdayName].end + ':00'
                             ).toDate(),
                             end: calendarDate.clone().add(1, 'day').toDate(),
                             allDay: false,
@@ -1405,9 +1410,7 @@ App.Utils.CalendarDefaultView = (function () {
 
                         const unavailabilityEvent = {
                             title: lang('break'),
-                            start: moment(
-                                calendarDate.format('YYYY-MM-DD') + ' ' + breakPeriod.start
-                            ).toDate(),
+                            start: moment(calendarDate.format('YYYY-MM-DD') + ' ' + breakPeriod.start).toDate(),
                             end: moment(calendarDate.format('YYYY-MM-DD') + ' ' + breakPeriod.end).toDate(),
                             allDay: false,
                             color: '#BEBEBE',
@@ -1420,7 +1423,6 @@ App.Utils.CalendarDefaultView = (function () {
 
                     calendarDate.add(1, 'day');
                 }
-
             })
             .always(() => {
                 $('#loading').css('visibility', '');
@@ -1562,7 +1564,10 @@ App.Utils.CalendarDefaultView = (function () {
 
         const localSelectFilterItemValue = window.localStorage.getItem('EasyAppointments.SelectFilterItem');
 
-        if (localSelectFilterItemValue && $selectFilterItem.find(`option[value="${localSelectFilterItemValue}"]`).length) {
+        if (
+            localSelectFilterItemValue &&
+            $selectFilterItem.find(`option[value="${localSelectFilterItemValue}"]`).length
+        ) {
             $selectFilterItem.val(localSelectFilterItemValue).trigger('change');
         } else {
             $reloadAppointments.trigger('click');
@@ -1601,6 +1606,11 @@ App.Utils.CalendarDefaultView = (function () {
             $appointmentsModal.find('#appointment-status').val(appointment.status);
             $appointmentsModal.find('#appointment-notes').val(appointment.notes);
             $appointmentsModal.find('#customer-notes').val(customer.notes);
+            $appointmentsModal.find('#custom-field-1').val(customer.custom_field_1);
+            $appointmentsModal.find('#custom-field-2').val(customer.custom_field_2);
+            $appointmentsModal.find('#custom-field-3').val(customer.custom_field_3);
+            $appointmentsModal.find('#custom-field-4').val(customer.custom_field_4);
+            $appointmentsModal.find('#custom-field-5').val(customer.custom_field_5);
 
             App.Components.ColorSelection.setColor($appointmentsModal.find('#appointment-color'), appointment.color);
 
diff --git a/assets/js/utils/calendar_table_view.js b/assets/js/utils/calendar_table_view.js
index 086abbc2..c1c50156 100755
--- a/assets/js/utils/calendar_table_view.js
+++ b/assets/js/utils/calendar_table_view.js
@@ -116,7 +116,7 @@ App.Utils.CalendarTableView = (function () {
                             createUnavailabilities($providerColumn, response.unavailabilities);
 
                             // Add the blocked periods to the column.
-                            createBlockedPeriods($providerColumn, response.blocked_periods); 
+                            createBlockedPeriods($providerColumn, response.blocked_periods);
 
                             // Add the provider breaks to the column.
                             const workingPlan = JSON.parse(provider.settings.working_plan);
@@ -232,6 +232,11 @@ App.Utils.CalendarTableView = (function () {
                 $appointmentsModal.find('#appointment-status').val(appointment.status);
                 $appointmentsModal.find('#appointment-notes').val(appointment.notes);
                 $appointmentsModal.find('#customer-notes').val(customer.notes);
+                $appointmentsModal.find('#custom-field-1').val(customer.custom_field_1);
+                $appointmentsModal.find('#custom-field-2').val(customer.custom_field_2);
+                $appointmentsModal.find('#custom-field-3').val(customer.custom_field_3);
+                $appointmentsModal.find('#custom-field-4').val(customer.custom_field_4);
+                $appointmentsModal.find('#custom-field-5').val(customer.custom_field_5);
 
                 App.Components.ColorSelection.setColor(
                     $appointmentsModal.find('#appointment-color'),
@@ -387,7 +392,9 @@ App.Utils.CalendarTableView = (function () {
         App.Utils.UI.initializeDatepicker($calendarHeader.find('.select-date'), {
             onChange(selectedDates) {
                 const startDate = selectedDates[0];
-                const endDate = moment(startDate).add(parseInt($selectFilterItem.val()) - 1, 'days').toDate();
+                const endDate = moment(startDate)
+                    .add(parseInt($selectFilterItem.val()) - 1, 'days')
+                    .toDate();
                 createView(startDate, endDate);
             }
         });
@@ -853,7 +860,7 @@ App.Utils.CalendarTableView = (function () {
             return;
         }
 
-        const filterServiceIds = $filterService.val().map(serviceId => Number(serviceId));
+        const filterServiceIds = $filterService.val().map((serviceId) => Number(serviceId));
 
         appointments = appointments.filter(
             (appointment) => !filterServiceIds.length || filterServiceIds.includes(appointment.id_services)
@@ -868,9 +875,7 @@ App.Utils.CalendarTableView = (function () {
                 continue;
             }
 
-            const title = [
-                appointment.service.name
-            ];
+            const title = [appointment.service.name];
 
             const customerInfo = [];
 
@@ -938,7 +943,7 @@ App.Utils.CalendarTableView = (function () {
 
         $providerColumn.find('.calendar-wrapper').data('fullCalendar').addEventSource(calendarEventSource);
     }
-    
+
     /**
      * Create Blocked Period Events
      *
@@ -1015,11 +1020,11 @@ App.Utils.CalendarTableView = (function () {
 
             $event.html(
                 lang('break') +
-                ' <span class="hour">' +
-                moment(eventDate).format('HH:mm') +
-                '</span> (' +
-                eventDuration +
-                "')"
+                    ' <span class="hour">' +
+                    moment(eventDate).format('HH:mm') +
+                    '</span> (' +
+                    eventDuration +
+                    "')"
             );
 
             $event.data(entry);
@@ -1199,8 +1204,8 @@ App.Utils.CalendarTableView = (function () {
                     $('<span/>', {
                         'text': info.event.extendedProps.data
                             ? info.event.extendedProps.data.provider.first_name +
-                            ' ' +
-                            info.event.extendedProps.data.provider.last_name
+                              ' ' +
+                              info.event.extendedProps.data.provider.last_name
                             : '-'
                     }),
                     $('<br/>'),
@@ -1212,8 +1217,8 @@ App.Utils.CalendarTableView = (function () {
                     $('<span/>', {
                         'text': App.Utils.Date.format(
                             info.event.extendedProps.data.date +
-                            ' ' +
-                            info.event.extendedProps.data.workingPlanException.start,
+                                ' ' +
+                                info.event.extendedProps.data.workingPlanException.start,
                             vars('date_format'),
                             vars('time_format'),
                             true
@@ -1228,8 +1233,8 @@ App.Utils.CalendarTableView = (function () {
                     $('<span/>', {
                         'text': App.Utils.Date.format(
                             info.event.extendedProps.data.date +
-                            ' ' +
-                            info.event.extendedProps.data.workingPlanException.end,
+                                ' ' +
+                                info.event.extendedProps.data.workingPlanException.end,
                             vars('date_format'),
                             vars('time_format'),
                             true
diff --git a/openapi.yml b/openapi.yml
index 284ed689..d0dd3b55 100644
--- a/openapi.yml
+++ b/openapi.yml
@@ -1902,6 +1902,16 @@ components:
           type: string
         language:
           type: string
+        customField1:
+          type: string
+        customField2:
+          type: string 
+        customField3:
+          type: string
+        customField4:
+          type: string
+        customField5:
+          type: string
         notes:
           type: string
       example:
@@ -1914,6 +1924,11 @@ components:
         zip: '12345'
         timezone: UTC
         language: english
+        customField1: Value1
+        customField2: Value2
+        customField3: Value3
+        customField4: Value4
+        customField5: Value5
         notes: This is a test customer.
     CustomerPayload:
       type: object
@@ -1936,6 +1951,16 @@ components:
           type: string
         language:
           type: string
+        customField1:
+          type: string
+        customField2:
+          type: string
+        customField3:
+          type: string
+        customField4:
+          type: string
+        customField5:
+          type: string
         notes:
           type: string
       example:
@@ -1947,6 +1972,11 @@ components:
         zip: '12345'
         timezone: UTC
         language: english
+        customField1: Value1
+        customField2: Value2
+        customField3: Value3
+        customField4: Value4
+        customField5: Value5
         notes: This is a test customer.
     CustomerCollection:
       type: array