diff --git a/exam/api/Login/Login.php b/exam/api/Login/Login.php
index 0fbcca6..70e979b 100644
--- a/exam/api/Login/Login.php
+++ b/exam/api/Login/Login.php
@@ -10,7 +10,7 @@ use Khofmann\Models\User\User;
 
 class Login extends Api
 {
-  public function post()
+  public function post(): void
   {
     $email = Input::post("email");
     if (empty($email)) throw new Exception("Missing email", 400);
@@ -18,7 +18,7 @@ class Login extends Api
     if (empty($password)) throw new Exception("Missing password", 400);
 
     try {
-      return Response::json(User::logIn($email, $password));
+      Response::json(User::logIn($email, $password));
     } catch (Exception $err) {
       switch ($err->getMessage()) {
         case "Failed":
diff --git a/exam/api/Logout/Logout.php b/exam/api/Logout/Logout.php
index 1cbdcb5..04f2806 100644
--- a/exam/api/Logout/Logout.php
+++ b/exam/api/Logout/Logout.php
@@ -9,9 +9,10 @@ use Khofmann\Response\Response;
 
 class Logout extends Api
 {
-  public function post()
+  public function post(): void
   {
     $token = Request::header("token");
-    return Response::json(User::getByToken($token)->logOut());
+
+    Response::json(User::getByToken($token)->logOut());
   }
 }
diff --git a/exam/api/Register/Register.php b/exam/api/Register/Register.php
index bc38868..a45ccc5 100644
--- a/exam/api/Register/Register.php
+++ b/exam/api/Register/Register.php
@@ -10,7 +10,7 @@ use Khofmann\Models\User\User;
 
 class Register extends Api
 {
-  public function post()
+  public function post(): void
   {
     $username = Input::post("username");
     if (empty($username)) throw new Exception("Missing username", 400);
@@ -20,7 +20,7 @@ class Register extends Api
     if (empty($password)) throw new Exception("Missing password", 400);
 
     try {
-      return Response::json(User::create($username, $email, $password));
+      Response::json(User::create($username, $email, $password));
     } catch (Exception $err) {
       switch ($err->getMessage()) {
         case "Duplicate":
diff --git a/exam/api/User/User.php b/exam/api/User/User.php
index 4683d8e..88c5b61 100644
--- a/exam/api/User/User.php
+++ b/exam/api/User/User.php
@@ -11,10 +11,10 @@ use Khofmann\Request\Request;
 
 class User extends Api
 {
-  public function get($id)
+  public function get($id): void
   {
     try {
-      return Response::json(MUser::getByID($id));
+      Response::json(MUser::getByID($id));
     } catch (Exception $err) {
       switch ($err->getMessage()) {
         case "NotFound":
@@ -25,14 +25,14 @@ class User extends Api
     }
   }
 
-  public function patch($id)
+  public function patch($id): void
   {
     $username = Input::patch("username");
     $password = Input::patch("password");
     $image = Input::file("image");
 
     try {
-      return Response::json(MUser::getByID($id)->update($username, $password, $image));
+      Response::json(MUser::getByID($id)->update($username, $password, $image));
     } catch (Exception $err) {
       switch ($err->getMessage()) {
         case "NotFound":
@@ -49,7 +49,7 @@ class User extends Api
     }
   }
 
-  public function patchSelf()
+  public function patchSelf(): void
   {
     $token = Request::header("token");
     $username = Input::patch("username");
@@ -57,7 +57,7 @@ class User extends Api
     $image = Input::file("image");
 
     try {
-      return Response::json(MUser::getByToken($token)->update($username, $password, $image));
+      Response::json(MUser::getByToken($token)->update($username, $password, $image));
     } catch (Exception $err) {
       switch ($err->getMessage()) {
         case "NotFound":
@@ -74,10 +74,10 @@ class User extends Api
     }
   }
 
-  public function delete($id)
+  public function delete($id): void
   {
     try {
-      return Response::json(MUser::getByID($id)->delete());
+      Response::json(MUser::getByID($id)->delete());
     } catch (Exception $err) {
       switch ($err->getMessage()) {
         case "NotFound":
diff --git a/exam/classes/Database/Database.php b/exam/classes/Database/Database.php
index c898014..c531687 100644
--- a/exam/classes/Database/Database.php
+++ b/exam/classes/Database/Database.php
@@ -8,7 +8,7 @@ class Database extends PDO
 {
   private static array $instances = [];
 
-  protected function __construct($dsn, $username = null, $password = null, array $options = null)
+  protected function __construct(string $dsn, string $username = null, string $password = null, array $options = null)
   {
     parent::__construct($dsn, $username, $password, $options);
   }
diff --git a/exam/classes/GUID/GUID.php b/exam/classes/GUID/GUID.php
index e14f503..c1df4af 100644
--- a/exam/classes/GUID/GUID.php
+++ b/exam/classes/GUID/GUID.php
@@ -4,7 +4,7 @@ namespace Khofmann\GUID;
 
 class GUID
 {
-  public static function v4($data = null)
+  public static function v4($data = null): string
   {
     // Generate 16 bytes (128 bits) of random data or use the data passed into the function.
     $data = $data ?? random_bytes(16);
diff --git a/exam/classes/Input/Input.php b/exam/classes/Input/Input.php
index 8ccec03..80aaebf 100644
--- a/exam/classes/Input/Input.php
+++ b/exam/classes/Input/Input.php
@@ -6,24 +6,22 @@ use Khofmann\Request\Request;
 
 class Input
 {
-
-
-  public static function post($index, $defaultValue = null)
+  public static function post(string $index, $defaultValue = null)
   {
     return Request::request()->getInputHandler()->post($index, $defaultValue);
   }
 
-  public static function patch($index, $defaultValue = null)
+  public static function patch(string $index, $defaultValue = null)
   {
     return Request::request()->getInputHandler()->post($index, $defaultValue);
   }
 
-  public static function get($index, $defaultValue = null)
+  public static function get(string $index, $defaultValue = null)
   {
     return Request::request()->getInputHandler()->get($index, $defaultValue);
   }
 
-  public static function file($index, $defaultValue = null)
+  public static function file(string $index, $defaultValue = null)
   {
     return Request::request()->getInputHandler()->file($index, $defaultValue);
   }
diff --git a/exam/classes/Models/User/User.php b/exam/classes/Models/User/User.php
index f7b0ec2..45f386b 100644
--- a/exam/classes/Models/User/User.php
+++ b/exam/classes/Models/User/User.php
@@ -155,7 +155,7 @@ class User implements JsonSerializable
     }
   }
 
-  public static function create(string $username, string $email, string $password)
+  public static function create(string $username, string $email, string $password): bool
   {
     $db = Database::getInstance();
     $guid = GUID::v4();
@@ -186,6 +186,10 @@ class User implements JsonSerializable
       throw $err;
     }
   }
+
+  public static function confirm(string $confirmCode): bool
+  {
+  }
   /*
   * Members
   */
@@ -198,7 +202,7 @@ class User implements JsonSerializable
     return $stmt->execute();
   }
 
-  public function update(?string $username, ?string $password, $image = null)
+  public function update(?string $username, ?string $password, $image = null): bool
   {
     $db = Database::getInstance();
 
@@ -233,7 +237,7 @@ class User implements JsonSerializable
     return true;
   }
 
-  public function delete()
+  public function delete(): bool
   {
     $db = Database::getInstance();
     $stmt = $db->prepare("DELETE FROM egb_benutzer WHERE id = :ID");
diff --git a/exam/classes/Request/Request.php b/exam/classes/Request/Request.php
index 048e72e..3b5e3ee 100644
--- a/exam/classes/Request/Request.php
+++ b/exam/classes/Request/Request.php
@@ -12,7 +12,7 @@ class Request
     return SimpleRouter::request();
   }
 
-  public static function header($name, $defaultValue = null, $tryParse = true)
+  public static function header(string $name, $defaultValue = null, bool $tryParse = true): ?string
   {
     return request()->getHeader($name, $defaultValue, $tryParse);
   }
diff --git a/exam/classes/Response/Response.php b/exam/classes/Response/Response.php
index 0457c96..bc66a6a 100644
--- a/exam/classes/Response/Response.php
+++ b/exam/classes/Response/Response.php
@@ -12,13 +12,13 @@ class Response
     return SimpleRouter::response();
   }
 
-  public static function json($value, int $options = 0, int $dept = 512)
+  public static function json($value, int $options = 0, int $dept = 512): void
   {
     if (is_bool($value)) {
       Response::response()->header('Content-Type: application/json; charset=utf-8');
       echo json_encode($value, $options, $dept);
       exit(0);
     }
-    return SimpleRouter::response()->json($value, $options, $dept);
+    SimpleRouter::response()->json($value, $options, $dept);
   }
 }
diff --git a/exam/config/Config.php b/exam/config/Config.php
index 4581b4d..768abda 100644
--- a/exam/config/Config.php
+++ b/exam/config/Config.php
@@ -34,22 +34,22 @@ class Config
     return self::$instances[$cls];
   }
 
-  public static function getBasePath()
+  public static function getBasePath(): string
   {
     return Config::getInstance()->app["basePath"];
   }
 
-  public static function getBaseFSPath()
+  public static function getBaseFSPath(): string
   {
     return Config::getInstance()->app["baseFSPath"];
   }
 
-  public static function getStoragePath()
+  public static function getStoragePath(): string
   {
     return Config::getInstance()->app["storagePath"];
   }
 
-  public static function getDatabase()
+  public static function getDatabase(): array
   {
     return Config::getInstance()->database;
   }
diff --git a/exam/utils/helpers.php b/exam/utils/helpers.php
index 019d138..67e226f 100644
--- a/exam/utils/helpers.php
+++ b/exam/utils/helpers.php
@@ -38,17 +38,3 @@ function redirect(string $url, ?int $code = null): void
 
     response()->redirect($url);
 }
-
-/**
- * Get current csrf-token
- * @return string|null
- */
-function csrf_token(): ?string
-{
-    $baseVerifier = Router::router()->getCsrfVerifier();
-    if ($baseVerifier !== null) {
-        return $baseVerifier->getTokenProvider()->getToken();
-    }
-
-    return null;
-}