diff --git a/app/Services/Hook.php b/app/Services/Hook.php
index 36754ae8..5900e540 100644
--- a/app/Services/Hook.php
+++ b/app/Services/Hook.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace App\Services;
 
 use Event;
@@ -23,7 +25,7 @@ class Hook
      * ]
      * @return void
      */
-    public static function addMenuItem($category, $position, array $menu)
+    public static function addMenuItem(string $category, int $position, array $menu): void
     {
         $class = 'App\Events\Configure'.Str::title($category).'Menu';
 
@@ -54,14 +56,14 @@ class Hook
      *
      * @param Closure $callback
      */
-    public static function addRoute(Closure $callback)
+    public static function addRoute(Closure $callback): void
     {
         Event::listen(Events\ConfigureRoutes::class, function ($event) use ($callback) {
             return call_user_func($callback, $event->router);
         });
     }
 
-    public static function registerPluginTransScripts($id, $pages = ['*'], $priority = 999)
+    public static function registerPluginTransScripts(string $id, $pages = ['*'], $priority = 999): void
     {
         Event::listen(Events\RenderingFooter::class, function ($event) use ($id, $pages) {
             foreach ($pages as $pattern) {
@@ -83,7 +85,7 @@ class Hook
         }, $priority);
     }
 
-    public static function addStyleFileToPage($urls, $pages = ['*'], $priority = 1)
+    public static function addStyleFileToPage($urls, $pages = ['*'], $priority = 1): void
     {
         Event::listen(Events\RenderingHeader::class, function ($event) use ($urls, $pages) {
             foreach ($pages as $pattern) {
@@ -100,7 +102,7 @@ class Hook
         }, $priority);
     }
 
-    public static function addScriptFileToPage($urls, $pages = ['*'], $priority = 1)
+    public static function addScriptFileToPage($urls, $pages = ['*'], $priority = 1): void
     {
         Event::listen(Events\RenderingFooter::class, function ($event) use ($urls, $pages) {
             foreach ($pages as $pattern) {
diff --git a/app/Services/Minecraft.php b/app/Services/Minecraft.php
index 05ce4193..aa671977 100644
--- a/app/Services/Minecraft.php
+++ b/app/Services/Minecraft.php
@@ -14,7 +14,7 @@ class Minecraft
      * @param  string $view   Which side of head to be captured, defaults to 'f' for front view.
      * @return resource
      */
-    public static function generateAvatarFromSkin($binary, $height, $view = 'f')
+    public static function generateAvatarFromSkin(string $binary, int $height, string $view = 'f')
     {
         $src = imagecreatefromstring($binary);
         $dest = imagecreatetruecolor($height, $height);
@@ -47,7 +47,7 @@ class Minecraft
      * @param  int    $gap    Gap size between front & back preview in relative pixel.
      * @return resource
      */
-    public static function generatePreviewFromSkin($binary, $height, $alex = false, $side = 'both', $gap = 4)
+    public static function generatePreviewFromSkin(string $binary, int $height, $alex = false, $side = 'both', $gap = 4)
     {
         $src = imagecreatefromstring($binary);
 
@@ -172,7 +172,7 @@ class Minecraft
      * @param  int    $fillHeight Set the value to 0 to disable.
      * @return resource
      */
-    public static function generatePreviewFromCape($binary, $height, $fillWidth = 0, $fillHeight = 0)
+    public static function generatePreviewFromCape(string $binary, int $height, $fillWidth = 0, $fillHeight = 0)
     {
         $src = imagecreatefromstring($binary);
         $ratio = imagesx($src) / 64;
diff --git a/app/Services/PackageManager.php b/app/Services/PackageManager.php
index 74cc9a5a..4f1ef5ef 100644
--- a/app/Services/PackageManager.php
+++ b/app/Services/PackageManager.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace App\Services;
 
 use Cache;
@@ -20,7 +22,7 @@ class PackageManager
         };
     }
 
-    public function download($url, $path, $shasum = null)
+    public function download(string $url, string $path, $shasum = null): self
     {
         $this->path = $path;
         $this->cacheKey = "download_$url";
@@ -44,7 +46,7 @@ class PackageManager
         return $this;
     }
 
-    public function extract($destination)
+    public function extract(string $destination): void
     {
         $zip = new \ZipArchive();
         $resource = $zip->open($this->path);
@@ -57,7 +59,7 @@ class PackageManager
         }
     }
 
-    public function progress()
+    public function progress(): float
     {
         $progress = unserialize(Cache::get($this->cacheKey));
         if ($progress['total'] == 0) {
diff --git a/app/Services/Plugin.php b/app/Services/Plugin.php
index 9e37268a..23d6f89f 100644
--- a/app/Services/Plugin.php
+++ b/app/Services/Plugin.php
@@ -1,8 +1,11 @@
 <?php
 
+declare(strict_types=1);
+
 namespace App\Services;
 
 use Illuminate\Support\Arr;
+use Illuminate\Support\Str;
 
 /**
  * @property string $name
@@ -61,79 +64,71 @@ class Plugin
      */
     protected $enabled = false;
 
-    /**
-     * @param       $path
-     * @param array $packageInfo
-     */
-    public function __construct($path, $packageInfo)
+    public function __construct(string $path, array $packageInfo)
     {
         $this->path = $path;
         $this->packageInfo = $packageInfo;
     }
 
-    public function __get($name)
+    public function __get(string $name)
     {
-        return $this->packageInfoAttribute(snake_case($name, '-'));
+        return $this->packageInfoAttribute(Str::snake($name, '-'));
     }
 
-    public function __isset($name)
+    public function __isset(string $name)
     {
         return isset($this->{$name}) || $this->packageInfoAttribute(snake_case($name, '-'));
     }
 
-    public function packageInfoAttribute($name)
+    public function packageInfoAttribute(string $name)
     {
         return Arr::get($this->packageInfo, $name);
     }
 
-    public function assets($relativeUri)
+    public function assets(string $relativeUri): string
     {
         $baseUrl = config('plugins.url') ?: url('plugins');
 
         return "$baseUrl/{$this->getDirname()}/assets/$relativeUri?v=".$this->version;
     }
 
-    /**
-     * @param bool $installed
-     * @return Plugin
-     */
-    public function setInstalled($installed)
+    public function setInstalled(bool $installed): self
     {
         $this->installed = $installed;
 
         return $this;
     }
 
-    public function getDirname()
+    public function getDirname(): string
     {
         return $this->dirname;
     }
 
-    public function setDirname($dirname)
+    public function setDirname(string $dirname): self
     {
         $this->dirname = $dirname;
 
         return $this;
     }
 
-    public function getNameSpace()
+    public function getNameSpace(): string
     {
         return $this->namespace;
     }
 
-    public function setNameSpace($namespace)
+    public function setNameSpace(string $namespace): self
     {
         $this->namespace = $namespace;
 
         return $this;
     }
 
-    public function getViewPath($name)
+    public function getViewPath(string $name): string
     {
         return $this->getViewPathByFileName("$name.tpl");
     }
 
-    public function getViewPathByFileName($filename)
+    public function getViewPathByFileName(string $filename): string
     {
         return $this->path."/views/$filename";
     }
@@ -143,74 +138,50 @@ class Plugin
         return $this->hasConfigView() ? view()->file($this->getViewPathByFileName(Arr::get($this->packageInfo, 'config'))) : null;
     }
 
-    public function hasConfigView()
+    public function hasConfigView(): bool
     {
         $filename = Arr::get($this->packageInfo, 'config');
 
         return $filename && file_exists($this->getViewPathByFileName($filename));
     }
 
-    /**
-     * @param string $version
-     * @return Plugin
-     */
-    public function setVersion($version)
+    public function setVersion(string $version): self
     {
         $this->version = $version;
 
         return $this;
     }
 
-    /**
-     * @return string
-     */
-    public function getVersion()
+    public function getVersion(): string
     {
         return $this->version;
     }
 
-    /**
-     * @param array $require
-     * @return Plugin
-     */
-    public function setRequirements($require)
+    public function setRequirements(array $require): self
     {
         $this->require = $require;
 
         return $this;
     }
 
-    /**
-     * @return array
-     */
-    public function getRequirements()
+    public function getRequirements(): array
     {
         return (array) $this->require;
     }
 
-    /**
-     * @param bool $enabled
-     * @return Plugin
-     */
-    public function setEnabled($enabled)
+    public function setEnabled(bool $enabled): self
     {
         $this->enabled = $enabled;
 
         return $this;
     }
 
-    /**
-     * @return bool
-     */
-    public function isEnabled()
+    public function isEnabled(): bool
     {
         return $this->enabled;
     }
 
-    /**
-     * @return string
-     */
-    public function getPath()
+    public function getPath(): string
     {
         return $this->path;
     }
diff --git a/app/Services/Webpack.php b/app/Services/Webpack.php
index 54748dc0..df33d695 100644
--- a/app/Services/Webpack.php
+++ b/app/Services/Webpack.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace App\Services;
 
 use File;
@@ -17,7 +19,7 @@ class Webpack
         }
     }
 
-    public function __get($path)
+    public function __get(string $path)
     {
         return Arr::get($this->manifest, $path, '');
     }
diff --git a/app/helpers.php b/app/helpers.php
index d968483e..fc3af916 100644
--- a/app/helpers.php
+++ b/app/helpers.php
@@ -1,12 +1,14 @@
 <?php
 
+declare(strict_types=1);
+
 use Carbon\Carbon;
 use App\Models\User;
 use Illuminate\Support\Arr;
 use Illuminate\Support\Str;
 
 if (! function_exists('webpack_assets')) {
-    function webpack_assets($relativeUri)
+    function webpack_assets(string $relativeUri): string
     {
         if (app()->environment('development')) {
             // @codeCoverageIgnoreStart
@@ -23,19 +25,14 @@ if (! function_exists('webpack_assets')) {
 }
 
 if (! function_exists('plugin')) {
-
-    /**
-     * @param string $id
-     * @return \App\Services\Plugin
-     */
-    function plugin($id)
+    function plugin(string $id)
     {
         return app('plugins')->getPlugin($id);
     }
 }
 
 if (! function_exists('plugin_assets')) {
-    function plugin_assets($id, $relativeUri)
+    function plugin_assets(string $id, string $relativeUri): string
     {
         if ($plugin = plugin($id)) {
             return $plugin->assets($relativeUri);
@@ -69,7 +66,7 @@ if (! function_exists('json')) {
 }
 
 if (! function_exists('bs_footer_extra')) {
-    function bs_footer_extra()
+    function bs_footer_extra(): string
     {
         $extraContents = [];
 
@@ -80,7 +77,7 @@ if (! function_exists('bs_footer_extra')) {
 }
 
 if (! function_exists('bs_header_extra')) {
-    function bs_header_extra()
+    function bs_header_extra(): string
     {
         $extraContents = [];
 
@@ -91,7 +88,7 @@ if (! function_exists('bs_header_extra')) {
 }
 
 if (! function_exists('bs_menu')) {
-    function bs_menu($type)
+    function bs_menu(string $type): string
     {
         $menu = config('menu');
 
@@ -139,7 +136,7 @@ if (! function_exists('bs_menu')) {
         return bs_menu_render($menu[$type]);
     }
 
-    function bs_menu_render($data)
+    function bs_menu_render(array $data): string
     {
         $content = '';
 
@@ -187,7 +184,7 @@ if (! function_exists('bs_menu')) {
 }
 
 if (! function_exists('bs_copyright')) {
-    function bs_copyright()
+    function bs_copyright(): string
     {
         return Arr::get(
             [
@@ -239,7 +236,7 @@ if (! function_exists('option_localized')) {
 }
 
 if (! function_exists('humanize_db_type')) {
-    function humanize_db_type($type = null)
+    function humanize_db_type($type = null): string
     {
         $map = [
             'mysql'  => 'MySQL',
@@ -271,7 +268,7 @@ if (! function_exists('format_http_date')) {
      * @param int $timestamp
      * @return string
      */
-    function format_http_date($timestamp)
+    function format_http_date($timestamp): string
     {
         return Carbon::createFromTimestampUTC($timestamp)->format('D, d M Y H:i:s \G\M\T');
     }
@@ -284,7 +281,7 @@ if (! function_exists('get_datetime_string')) {
      * @param int $timestamp
      * @return string
      */
-    function get_datetime_string($timestamp = 0)
+    function get_datetime_string($timestamp = 0): string
     {
         return $timestamp == 0 ? Carbon::now()->toDateTimeString() : Carbon::createFromTimestamp($timestamp)->toDateTimeString();
     }
@@ -299,7 +296,7 @@ if (! function_exists('get_client_ip')) {
      *
      * @return string
      */
-    function get_client_ip()
+    function get_client_ip(): string
     {
         if (option('ip_get_method') == '0') {
             // Use `HTTP_X_FORWARDED_FOR` if available first
@@ -330,7 +327,7 @@ if (! function_exists('get_string_replaced')) {
      * @param  array  $rules
      * @return string
      */
-    function get_string_replaced($str, $rules)
+    function get_string_replaced(string $str, array $rules): string
     {
         foreach ($rules as $search => $replace) {
             $str = str_replace($search, $replace, $str);
@@ -350,7 +347,7 @@ if (! function_exists('is_request_secure')) {
      *
      * @return bool
      */
-    function is_request_secure()
+    function is_request_secure(): bool
     {
         if (Arr::get($_SERVER, 'HTTPS') == 'on') {
             return true;
@@ -375,7 +372,7 @@ if (! function_exists('nl2p')) {
      * @param string $text
      * @return string
      */
-    function nl2p($text)
+    function nl2p(string $text): string
     {
         $parts = explode("\n", $text);
         $result = '<p>'.implode('</p><p>', $parts).'</p>';
diff --git a/tests/Concerns/FakePackageManager.php b/tests/Concerns/FakePackageManager.php
index 60cb8f57..02c3f5fa 100644
--- a/tests/Concerns/FakePackageManager.php
+++ b/tests/Concerns/FakePackageManager.php
@@ -1,8 +1,12 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Tests\Concerns;
 
-class FakePackageManager extends \App\Services\PackageManager
+use App\Services\PackageManager;
+
+class FakePackageManager extends PackageManager
 {
     private $throw;
 
@@ -12,7 +16,7 @@ class FakePackageManager extends \App\Services\PackageManager
         $this->throw = $throw;
     }
 
-    public function download($url, $path, $shasum = null)
+    public function download(string $url, string $path, $shasum = null): PackageManager
     {
         if ($this->throw) {
             throw new \Exception('');
@@ -21,13 +25,13 @@ class FakePackageManager extends \App\Services\PackageManager
         }
     }
 
-    public function extract($destination)
+    public function extract(string $destination): void
     {
-        return true;
+        //
     }
 
-    public function progress()
+    public function progress(): float
     {
-        return '0';
+        return 0.0;
     }
 }