diff --git a/includes/engelsystem_provider.php b/includes/engelsystem_provider.php
index 65a319e9..aed331d4 100644
--- a/includes/engelsystem_provider.php
+++ b/includes/engelsystem_provider.php
@@ -6,6 +6,7 @@ use Engelsystem\Exceptions\Handler as ExceptionHandler;
 use Engelsystem\Http\Request;
 use Engelsystem\Renderer\HtmlEngine;
 use Engelsystem\Renderer\Renderer;
+use Symfony\Component\HttpFoundation\Session\Session;
 
 /**
  * This file includes all needed functions, connects to the db etc.
@@ -169,7 +170,9 @@ foreach ($includeFiles as $file) {
 /**
  * Init application
  */
-session_start();
+$session = new Session();
+$session->start();
+$request->setSession($session);
 
 gettext_init();
 
diff --git a/includes/helper/internationalization_helper.php b/includes/helper/internationalization_helper.php
index 83faabb0..131941e9 100644
--- a/includes/helper/internationalization_helper.php
+++ b/includes/helper/internationalization_helper.php
@@ -9,7 +9,7 @@ use Engelsystem\Http\Request;
  */
 function locale()
 {
-    return $_SESSION['locale'];
+    return session()->get('locale');
 }
 
 /**
@@ -29,11 +29,12 @@ function gettext_init()
 {
     $locales = config('locales');
     $request = request();
+    $session = session();
 
     if ($request->has('set_locale') && isset($locales[$request->input('set_locale')])) {
-        $_SESSION['locale'] = $request->input('set_locale');
-    } elseif (!isset($_SESSION['locale'])) {
-        $_SESSION['locale'] = config('default_locale');
+        $session->set('locale', $request->input('set_locale'));
+    } elseif (!$session->has('locale')) {
+        $session->set('locale', config('default_locale'));
     }
 
     gettext_locale();
@@ -50,7 +51,7 @@ function gettext_init()
 function gettext_locale($locale = null)
 {
     if ($locale == null) {
-        $locale = $_SESSION['locale'];
+        $locale = session()->get('locale');
     }
 
     putenv('LC_ALL=' . $locale);
diff --git a/includes/helper/message_helper.php b/includes/helper/message_helper.php
index 1f429c27..7a42a7b7 100644
--- a/includes/helper/message_helper.php
+++ b/includes/helper/message_helper.php
@@ -7,12 +7,12 @@
  */
 function msg()
 {
-    if (!isset($_SESSION['msg'])) {
-        return '';
-    }
-    $msg = $_SESSION['msg'];
-    $_SESSION['msg'] = '';
-    return $msg;
+    $session = session();
+
+    $message = $session->get('msg', '');
+    $session->set('msg', '');
+
+    return $message;
 }
 
 /**
@@ -61,6 +61,8 @@ function success($msg, $immediately = false)
  */
 function alert($class, $msg, $immediately = false)
 {
+    $session = session();
+
     if ($immediately) {
         if ($msg == '') {
             return '';
@@ -68,10 +70,9 @@ function alert($class, $msg, $immediately = false)
         return '<div class="alert alert-' . $class . '">' . $msg . '</div>';
     }
 
-    if (!isset($_SESSION['msg'])) {
-        $_SESSION['msg'] = '';
-    }
-    $_SESSION['msg'] .= alert($class, $msg, true);
+    $message = $session->get('msg', '');
+    $message .= alert($class, $msg, true);
+    $session->set('msg', $message);
 
     return null;
 }
diff --git a/includes/pages/admin_shifts.php b/includes/pages/admin_shifts.php
index 04d88a4f..c77bd46d 100644
--- a/includes/pages/admin_shifts.php
+++ b/includes/pages/admin_shifts.php
@@ -19,6 +19,7 @@ function admin_shifts()
 {
     $valid = true;
     $request = request();
+    $session = session();
     $start = parse_date('Y-m-d H:i', date('Y-m-d') . ' 00:00');
     $end = $start;
     $mode = 'single';
@@ -270,8 +271,8 @@ function admin_shifts()
             }
 
             // Fürs Anlegen zwischenspeichern:
-            $_SESSION['admin_shifts_shifts'] = $shifts;
-            $_SESSION['admin_shifts_types'] = $needed_angel_types;
+            $session->set('admin_shifts_shifts', $shifts);
+            $session->set('admin_shifts_types', $needed_angel_types);
 
             $hidden_types = '';
             foreach ($needed_angel_types as $type_id => $count) {
@@ -301,16 +302,14 @@ function admin_shifts()
         }
     } elseif ($request->has('submit')) {
         if (
-            !isset($_SESSION['admin_shifts_shifts'])
-            || !isset($_SESSION['admin_shifts_types'])
-            || !is_array($_SESSION['admin_shifts_shifts'])
-            || !is_array($_SESSION['admin_shifts_types'])
+            !is_array($session->get('admin_shifts_shifts'))
+            || !is_array($session->get('admin_shifts_types'))
         ) {
             redirect(page_link_to('admin_shifts'));
         }
 
         $needed_angel_types_info = [];
-        foreach ($_SESSION['admin_shifts_shifts'] as $shift) {
+        foreach ($session->get('admin_shifts_shifts', []) as $shift) {
             $shift['URL'] = null;
             $shift['PSID'] = null;
             $shift_id = Shift_create($shift);
@@ -322,7 +321,7 @@ function admin_shifts()
                 . ' to ' . date('Y-m-d H:i', $shift['end'])
             );
 
-            foreach ($_SESSION['admin_shifts_types'] as $type_id => $count) {
+            foreach ($session->get('admin_shifts_types', []) as $type_id => $count) {
                 $angel_type_source = DB::selectOne('
                       SELECT *
                       FROM `AngelTypes`
@@ -348,8 +347,8 @@ function admin_shifts()
         success('Schichten angelegt.');
         redirect(page_link_to('admin_shifts'));
     } else {
-        unset($_SESSION['admin_shifts_shifts']);
-        unset($_SESSION['admin_shifts_types']);
+        $session->remove('admin_shifts_shifts');
+        $session->remove('admin_shifts_types');
     }
 
     $rid = null;
diff --git a/includes/pages/guest_login.php b/includes/pages/guest_login.php
index 4a77b40c..9179c6c4 100644
--- a/includes/pages/guest_login.php
+++ b/includes/pages/guest_login.php
@@ -39,6 +39,7 @@ function guest_register()
     $min_password_length = config('min_password_length');
     $event_config = EventConfig();
     $request = request();
+    $session = session();
 
     $msg = '';
     $nick = '';
@@ -226,7 +227,7 @@ function guest_register()
                     $password_hash,
                     $comment,
                     $hometown,
-                    $_SESSION['locale'],
+                    $session->get('locale'),
                     $planned_arrival_date,
                 ]
             );
@@ -377,25 +378,36 @@ function guest_register()
     ]);
 }
 
+/**
+ * @return string
+ */
 function entry_required()
 {
     return '<span class="text-info glyphicon glyphicon-warning-sign"></span>';
 }
 
+/**
+ * @return bool
+ */
 function guest_logout()
 {
-    session_destroy();
+    session()->invalidate();
     redirect(page_link_to('start'));
     return true;
 }
 
+/**
+ * @return string
+ */
 function guest_login()
 {
     $nick = '';
     $request = request();
-    unset($_SESSION['uid']);
+    $session = session();
     $valid = true;
 
+    $session->remove('uid');
+
     if ($request->has('submit')) {
         if ($request->has('nick') && strlen(User_validate_Nick($request->input('nick'))) > 0) {
             $nick = User_validate_Nick($request->input('nick'));
@@ -420,8 +432,8 @@ function guest_login()
         }
 
         if ($valid && !empty($login_user)) {
-            $_SESSION['uid'] = $login_user['UID'];
-            $_SESSION['locale'] = $login_user['Sprache'];
+            $session->set('uid', $login_user['UID']);
+            $session->set('locale', $login_user['Sprache']);
 
             redirect(page_link_to('news'));
         }
@@ -477,6 +489,9 @@ function guest_login()
     ]);
 }
 
+/**
+ * @return string
+ */
 function get_register_hint()
 {
     global $privileges;
diff --git a/includes/pages/user_settings.php b/includes/pages/user_settings.php
index 03621a45..0ba8bbcb 100644
--- a/includes/pages/user_settings.php
+++ b/includes/pages/user_settings.php
@@ -164,6 +164,7 @@ function user_settings_locale($user_source, $locales)
 {
     $valid = true;
     $request = request();
+    $session = session();
 
     if ($request->has('language') && isset($locales[$request->input('language')])) {
         $user_source['Sprache'] = $request->input('language');
@@ -182,7 +183,7 @@ function user_settings_locale($user_source, $locales)
                 $user_source['UID'],
             ]
         );
-        $_SESSION['locale'] = $user_source['Sprache'];
+        $session->set('locale', $user_source['Sprache']);
 
         success('Language changed.');
         redirect(page_link_to('user_settings'));
diff --git a/includes/pages/user_shifts.php b/includes/pages/user_shifts.php
index db0bb193..30abbde6 100644
--- a/includes/pages/user_shifts.php
+++ b/includes/pages/user_shifts.php
@@ -167,20 +167,23 @@ function view_user_shifts()
 {
     global $user, $privileges, $ical_shifts;
 
+    $session = session();
     $ical_shifts = [];
     $days = load_days();
     $rooms = load_rooms();
     $types = load_types();
 
-    if (!isset($_SESSION['ShiftsFilter'])) {
+    if (!$session->has('ShiftsFilter')) {
         $room_ids = [
             $rooms[0]['id']
         ];
         $type_ids = array_map('get_ids_from_array', $types);
-        $_SESSION['ShiftsFilter'] = new ShiftsFilter(in_array('user_shifts_admin', $privileges), $room_ids, $type_ids);
+        $shiftsFilter = new ShiftsFilter(in_array('user_shifts_admin', $privileges), $room_ids, $type_ids);
+        $session->set('ShiftsFilter', $shiftsFilter);
     }
-    update_ShiftsFilter($_SESSION['ShiftsFilter'], in_array('user_shifts_admin', $privileges), $days);
-    $shiftsFilter = $_SESSION['ShiftsFilter'];
+
+    $shiftsFilter = $session->get('ShiftsFilter');
+    update_ShiftsFilter($shiftsFilter, in_array('user_shifts_admin', $privileges), $days);
 
     $shiftCalendarRenderer = shiftCalendarRendererByShiftFilter($shiftsFilter);
 
diff --git a/includes/sys_auth.php b/includes/sys_auth.php
index 36f0f935..4242261b 100644
--- a/includes/sys_auth.php
+++ b/includes/sys_auth.php
@@ -10,8 +10,10 @@ function load_auth()
     global $user, $privileges;
 
     $user = null;
-    if (isset($_SESSION['uid'])) {
-        $user = DB::selectOne('SELECT * FROM `User` WHERE `UID`=? LIMIT 1', [$_SESSION['uid']]);
+    $session = session();
+
+    if ($session->has('uid')) {
+        $user = DB::selectOne('SELECT * FROM `User` WHERE `UID`=? LIMIT 1', [$session->get('uid')]);
         if (!empty($user)) {
             // User ist eingeloggt, Datensatz zur Verfügung stellen und Timestamp updaten
             DB::update('
@@ -21,12 +23,13 @@ function load_auth()
                 LIMIT 1
             ', [
                 time(),
-                $_SESSION['uid'],
+                $session->get('uid'),
             ]);
             $privileges = privileges_for_user($user['UID']);
             return;
         }
-        unset($_SESSION['uid']);
+
+        $session->remove('uid');
     }
 
     // guest privileges
diff --git a/src/helpers.php b/src/helpers.php
index af0e802b..24f93f2c 100644
--- a/src/helpers.php
+++ b/src/helpers.php
@@ -5,6 +5,7 @@ use Engelsystem\Config\Config;
 use Engelsystem\Http\Request;
 use Engelsystem\Renderer\Renderer;
 use Engelsystem\Routing\UrlGenerator;
+use Symfony\Component\HttpFoundation\Session\SessionInterface;
 
 /**
  * Get or set config values
@@ -42,6 +43,22 @@ function request($key = null, $default = null)
     return $request->input($key, $default);
 }
 
+/**
+ * @param string $key
+ * @param mixed  $default
+ * @return SessionInterface|mixed
+ */
+function session($key = null, $default = null)
+{
+    $session = request()->getSession();
+
+    if (is_null($key)) {
+        return $session;
+    }
+
+    return $session->get($key, $default);
+}
+
 /**
  * @param string  $template
  * @param mixed[] $data