diff --git a/.gitignore b/.gitignore
index fe85b539..3b89caf4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,6 +16,7 @@ Thumbs.db
 # Test & Runtime artifacts
 # =========================
 /tests/_root/shared/store/*
+/tests/_root/cron-tests/
 /coverage/
 *.log
 
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
index 159c9b14..706c07c3 100644
--- a/phpstan.neon.dist
+++ b/phpstan.neon.dist
@@ -1,6 +1,6 @@
 parameters:
     phpVersion: 70400
-    level: 6
+    level: 7
 
     paths:
         - src
diff --git a/src/App/Adapters/ConsoleAppAdapter.php b/src/App/Adapters/ConsoleAppAdapter.php
index e2b86d87..4d2875f5 100644
--- a/src/App/Adapters/ConsoleAppAdapter.php
+++ b/src/App/Adapters/ConsoleAppAdapter.php
@@ -44,7 +44,7 @@ class ConsoleAppAdapter extends AppAdapter
 
     protected ConsoleOutput $output;
 
-    protected ?Application $application = null;
+    protected Application $application;
 
     public function __construct()
     {
@@ -59,6 +59,11 @@ public function __construct()
             $this->loadEnvironment();
             $this->loadAppConfig();
         }
+
+        $this->application = $this->createApplication(
+            config()->get('app.name', 'UNKNOWN'),
+            config()->get('app.version', 'UNKNOWN')
+        );
     }
 
     /**
@@ -72,11 +77,6 @@ public function __construct()
     public function start(): ?int
     {
         try {
-            $this->application = $this->createApplication(
-                config()->get('app.name', 'UNKNOWN'),
-                config()->get('app.version', 'UNKNOWN')
-            );
-
             $this->loadLanguage();
 
             $this->registerCoreCommands();
diff --git a/src/App/Adapters/WebAppAdapter.php b/src/App/Adapters/WebAppAdapter.php
index 39681c5d..9dc0cf61 100644
--- a/src/App/Adapters/WebAppAdapter.php
+++ b/src/App/Adapters/WebAppAdapter.php
@@ -146,7 +146,7 @@ public function start(): ?int
 
             $viewCache = $this->setupViewCache();
 
-            if ($viewCache->serveCachedView(route_uri(), $this->response)) {
+            if ($viewCache->serveCachedView(route_uri() ?? '', $this->response)) {
                 stop();
             }
 
diff --git a/src/App/App.php b/src/App/App.php
index 467d101f..406ba8f3 100644
--- a/src/App/App.php
+++ b/src/App/App.php
@@ -19,6 +19,7 @@
 use Quantum\App\Exceptions\BaseException;
 use Quantum\App\Exceptions\AppException;
 use Quantum\App\Contracts\AppInterface;
+use RuntimeException;
 
 /**
  * Class App
@@ -42,6 +43,10 @@ public static function setBaseDir(string $baseDir): void
 
     public static function getBaseDir(): string
     {
+        if (self::$baseDir === null || self::$baseDir === '') {
+            throw new RuntimeException('Base directory is not initialized.');
+        }
+
         return self::$baseDir;
     }
 
diff --git a/src/App/Exceptions/StopExecutionException.php b/src/App/Exceptions/StopExecutionException.php
index 8512dcc5..f8c5e06d 100644
--- a/src/App/Exceptions/StopExecutionException.php
+++ b/src/App/Exceptions/StopExecutionException.php
@@ -28,7 +28,7 @@ public static function executionTerminated(?int $code): self
     {
         return new self(
             ExceptionMessages::EXECUTION_TERMINATED,
-            $code
+            $code ?? 0
         );
     }
 }
diff --git a/src/App/Helpers/misc.php b/src/App/Helpers/misc.php
index f51371ee..f4a333bc 100644
--- a/src/App/Helpers/misc.php
+++ b/src/App/Helpers/misc.php
@@ -24,9 +24,9 @@ function _message(string $subject, $params): string
     if (is_array($params)) {
         return preg_replace_callback('/{%\d+}/', function () use (&$params) {
             return array_shift($params);
-        }, $subject);
+        }, $subject) ?? $subject;
     } else {
-        return preg_replace('/{%\d+}/', $params, $subject);
+        return preg_replace('/{%\d+}/', $params, $subject) ?? $subject;
     }
 }
 
@@ -62,8 +62,8 @@ function random_number(int $length = 10): int
 function slugify(string $text): string
 {
     $text = trim($text, ' ');
-    $text = preg_replace('/[^\p{L}\p{N}]/u', ' ', $text);
-    $text = preg_replace('/\s+/', '-', $text);
+    $text = preg_replace('/[^\p{L}\p{N}]/u', ' ', $text) ?? $text;
+    $text = preg_replace('/\s+/', '-', $text) ?? $text;
     $text = trim($text, '-');
     $text = mb_strtolower($text);
 
diff --git a/src/App/Traits/AppTrait.php b/src/App/Traits/AppTrait.php
index 262ce94f..620cb44c 100644
--- a/src/App/Traits/AppTrait.php
+++ b/src/App/Traits/AppTrait.php
@@ -76,7 +76,9 @@ protected function loadComponentHelperFunctions(): void
 
         $srcDir = dirname(__DIR__, 2);
 
-        foreach (glob($srcDir . DS . '*', GLOB_ONLYDIR) as $componentDir) {
+        $componentDirs = glob($srcDir . DS . '*', GLOB_ONLYDIR);
+
+        foreach (is_array($componentDirs) ? $componentDirs : [] as $componentDir) {
             $helperPath = $componentDir . DS . 'Helpers';
             if (is_dir($helperPath)) {
                 $loader->loadDir($helperPath);
diff --git a/src/App/Traits/ConsoleAppTrait.php b/src/App/Traits/ConsoleAppTrait.php
index 04f60052..85c2be9b 100644
--- a/src/App/Traits/ConsoleAppTrait.php
+++ b/src/App/Traits/ConsoleAppTrait.php
@@ -17,6 +17,7 @@
 namespace Quantum\App\Traits;
 
 use Quantum\Environment\Exceptions\EnvException;
+use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Application;
 use Quantum\App\Exceptions\BaseException;
 use Quantum\Di\Exceptions\DiException;
@@ -80,7 +81,10 @@ private function registerCommands(string $directory, string $namespace): void
         $commands = CommandDiscovery::discover($directory, $namespace);
 
         foreach ($commands as $command) {
-            $this->application->add(new $command['class']());
+            $instance = new $command['class']();
+            if ($instance instanceof Command) {
+                $this->application->add($instance);
+            }
         }
     }
 
@@ -91,7 +95,7 @@ private function validateCommand(): void
     {
         $commandName = $this->input->getFirstArgument();
 
-        if (!$this->application->has($commandName)) {
+        if ($commandName === null || !$this->application->has($commandName)) {
             throw new Exception("Command `$commandName` is not defined");
         }
     }
diff --git a/src/Archive/Adapters/PharAdapter.php b/src/Archive/Adapters/PharAdapter.php
index 163c7e3e..c9c9a882 100644
--- a/src/Archive/Adapters/PharAdapter.php
+++ b/src/Archive/Adapters/PharAdapter.php
@@ -107,7 +107,9 @@ public function addFile(string $filePath, ?string $entryName = null): bool
         }
 
         try {
-            $this->archive->addFile($filePath, $entryName);
+            $entryName !== null
+                ? $this->archive->addFile($filePath, $entryName)
+                : $this->archive->addFile($filePath);
             return true;
         } catch (Exception $e) {
             return false;
@@ -213,6 +215,8 @@ public function deleteMultipleFiles(array $fileNames): bool
 
     /**
      * @throws ArchiveException
+     * @phpstan-assert Phar $this->archive
+     * @phpstan-assert string $this->archiveName
      */
     private function ensureArchiveOpen(): void
     {
diff --git a/src/Archive/Adapters/ZipAdapter.php b/src/Archive/Adapters/ZipAdapter.php
index c7b4b19a..3129adbf 100644
--- a/src/Archive/Adapters/ZipAdapter.php
+++ b/src/Archive/Adapters/ZipAdapter.php
@@ -94,7 +94,9 @@ public function addFile(string $filePath, ?string $entryName = null): bool
             throw ArchiveException::fileNotFound($filePath);
         }
 
-        $result = $this->archive->addFile($filePath, $entryName);
+        $result = $entryName !== null
+            ? $this->archive->addFile($filePath, $entryName)
+            : $this->archive->addFile($filePath);
         $this->requiresReopen = true;
 
         return $result;
@@ -195,6 +197,7 @@ public function deleteMultipleFiles(array $fileNames): bool
 
     /**
      * @throws ArchiveException
+     * @phpstan-assert ZipArchive $this->archive
      */
     private function ensureArchiveOpen(): void
     {
diff --git a/src/Asset/Asset.php b/src/Asset/Asset.php
index 6ed96e9f..64ab140a 100644
--- a/src/Asset/Asset.php
+++ b/src/Asset/Asset.php
@@ -43,7 +43,7 @@ class Asset
      */
     private ?array $attributes;
 
-    private ?int $position;
+    private int $position;
 
     /**
      * Asset templates
@@ -58,7 +58,7 @@ class Asset
      * Asset constructor
      * @param array<string>|null $attributes
      */
-    public function __construct(int $type, string $path, ?string $name = null, ?int $position = -1, ?array $attributes = [])
+    public function __construct(int $type, string $path, ?string $name = null, int $position = -1, ?array $attributes = [])
     {
         $this->type = $type;
         $this->path = $path;
@@ -76,7 +76,7 @@ public function getType(): int
     }
 
     /**
-     * Gets asset path
+     * Gets an asset path
      */
     public function getPath(): string
     {
@@ -94,7 +94,7 @@ public function getName(): ?string
     /**
      * Gets asset position
      */
-    public function getPosition(): ?int
+    public function getPosition(): int
     {
         return $this->position;
     }
@@ -127,7 +127,7 @@ public function tag(): string
     {
         return _message(
             $this->templates[$this->type],
-            [$this->url(), implode(' ', $this->attributes)]
+            [$this->url(), implode(' ', $this->attributes ?? [])]
         ) . PHP_EOL;
     }
 }
diff --git a/src/Asset/AssetManager.php b/src/Asset/AssetManager.php
index 03f31811..1c81558e 100644
--- a/src/Asset/AssetManager.php
+++ b/src/Asset/AssetManager.php
@@ -169,7 +169,7 @@ private function setPriorityAssets(): void
             $position = $asset->getPosition();
             $type = $asset->getType();
 
-            if ($position != -1) {
+            if ($position !== -1) {
                 if (isset($this->published[$type][$position])) {
                     throw AssetException::positionInUse($position, $asset->getPath());
                 }
@@ -185,7 +185,7 @@ private function setPriorityAssets(): void
     private function setRegularAssets(): void
     {
         foreach ($this->store as $asset) {
-            if ($asset->getPosition() == -1) {
+            if ($asset->getPosition() === -1) {
                 $this->setPosition($asset, 0);
             }
         }
diff --git a/src/Auth/Adapters/JwtAuthAdapter.php b/src/Auth/Adapters/JwtAuthAdapter.php
index 853b9dc5..daed3a4b 100644
--- a/src/Auth/Adapters/JwtAuthAdapter.php
+++ b/src/Auth/Adapters/JwtAuthAdapter.php
@@ -38,10 +38,12 @@ class JwtAuthAdapter implements AuthenticatableInterface
 {
     use AuthTrait;
 
+    protected JwtToken $jwt;
+
     /**
      * @throws AuthException
      */
-    public function __construct(AuthServiceInterface $authService, Mailer $mailer, Hasher $hasher, ?JwtToken $jwt = null)
+    public function __construct(AuthServiceInterface $authService, Mailer $mailer, Hasher $hasher, JwtToken $jwt)
     {
         $this->authService = $authService;
         $this->mailer = $mailer;
@@ -138,11 +140,12 @@ public function verifyOtp(int $otp, string $otpToken): array
 
     /**
      * Get Updated Tokens
-     * @throws JwtException
      * @return array<string, string>
+     * @throws JwtException
      */
     protected function getUpdatedTokens(User $user): array
     {
+
         return [
             $this->keyFields[AuthKeys::REFRESH_TOKEN] => $this->generateToken(),
             $this->keyFields[AuthKeys::ACCESS_TOKEN] => base64_encode($this->jwt->setData($this->getVisibleFields($user))->compose()),
@@ -151,8 +154,8 @@ protected function getUpdatedTokens(User $user): array
 
     /**
      * Set Updated Tokens
-     * @throws JwtException
      * @return array<string, string>
+     * @throws JwtException
      */
     protected function setUpdatedTokens(User $user): array
     {
diff --git a/src/Auth/Factories/AuthFactory.php b/src/Auth/Factories/AuthFactory.php
index c2e486cc..985b4f2a 100644
--- a/src/Auth/Factories/AuthFactory.php
+++ b/src/Auth/Factories/AuthFactory.php
@@ -16,14 +16,15 @@
 
 namespace Quantum\Auth\Factories;
 
+use Quantum\Auth\Contracts\AuthenticatableInterface;
 use Quantum\Auth\Contracts\AuthServiceInterface;
 use Quantum\Service\Exceptions\ServiceException;
 use Quantum\Config\Exceptions\ConfigException;
 use Quantum\Service\Factories\ServiceFactory;
 use Quantum\Auth\Adapters\SessionAuthAdapter;
 use Quantum\Auth\Exceptions\AuthException;
-use Quantum\Auth\Adapters\JwtAuthAdapter;
 use Quantum\App\Exceptions\BaseException;
+use Quantum\Auth\Adapters\JwtAuthAdapter;
 use Quantum\Di\Exceptions\DiException;
 use Quantum\Auth\Enums\AuthType;
 use Quantum\Service\QtService;
@@ -87,12 +88,17 @@ public static function get(?string $adapter = null): Auth
      */
     private static function createInstance(string $adapterClass, string $adapter): Auth
     {
-        return new Auth(new $adapterClass(
-            self::createAuthService($adapter),
-            mailer(),
-            new Hasher(),
-            self::createJwtInstance($adapter)
-        ));
+        $authService = self::createAuthService($adapter);
+
+        $adapterInstance = $adapter === AuthType::JWT
+            ? new $adapterClass($authService, mailer(), new Hasher(), self::createJwtInstance())
+            : new $adapterClass($authService, mailer(), new Hasher());
+
+        if (!$adapterInstance instanceof AuthenticatableInterface) {
+            throw AuthException::adapterNotSupported($adapter);
+        }
+
+        return new Auth($adapterInstance);
     }
 
     /**
@@ -127,8 +133,10 @@ private static function createAuthService(string $adapter): AuthServiceInterface
         return $authService;
     }
 
-    private static function createJwtInstance(string $adapter): ?JwtToken
+    private static function createJwtInstance(): JwtToken
     {
-        return $adapter === AuthType::JWT ? (new JwtToken())->setLeeway(1)->setClaims((array) config()->get('auth.claims')) : null;
+        return (new JwtToken())
+            ->setLeeway(1)
+            ->setClaims((array) config()->get('auth.' . AuthType::JWT . '.claims'));
     }
 }
diff --git a/src/Auth/Traits/AuthTrait.php b/src/Auth/Traits/AuthTrait.php
index ccec97da..5a4c7505 100644
--- a/src/Auth/Traits/AuthTrait.php
+++ b/src/Auth/Traits/AuthTrait.php
@@ -25,7 +25,6 @@
 use Quantum\Auth\Enums\AuthKeys;
 use Quantum\Mailer\Mailer;
 use Quantum\Hasher\Hasher;
-use Quantum\Jwt\JwtToken;
 use ReflectionException;
 use Quantum\Auth\User;
 use ReflectionClass;
@@ -39,40 +38,23 @@
  */
 trait AuthTrait
 {
-    /**
-     * @var Mailer
-     */
-    protected $mailer;
-
-    /**
-     * @var Hasher
-     */
-    protected $hasher;
+    protected Mailer $mailer;
 
-    /**
-     * @var JwtToken
-     */
-    protected $jwt;
+    protected Hasher $hasher;
 
-    /**
-     * @var AuthServiceInterface
-     */
-    protected $authService;
+    protected AuthServiceInterface $authService;
 
-    /**
-     * @var int
-     */
-    protected $otpLength = 6;
+    protected int $otpLength = 6;
 
     /**
      * @var array<string, string>
      */
-    protected $keyFields = [];
+    protected array $keyFields = [];
 
     /**
      * @var array<string>
      */
-    protected $visibleFields = [];
+    protected array $visibleFields = [];
 
     /**
      * @inheritDoc
@@ -214,7 +196,7 @@ protected function getUser(string $username, string $password): User
             throw AuthException::incorrectCredentials();
         }
 
-        if (!$this->hasher->check($password, $user->getFieldValue($this->keyFields[AuthKeys::PASSWORD]))) {
+        if (!$this->hasher->check($password, $user->getFieldValue($this->keyFields[AuthKeys::PASSWORD]) ?? '')) {
             throw AuthException::incorrectCredentials();
         }
 
@@ -275,7 +257,9 @@ protected function verifyAndUpdateOtp(int $otp, string $otpToken): User
             throw AuthException::incorrectVerificationCode();
         }
 
-        if (new DateTime() >= new DateTime($user->getFieldValue($this->keyFields[AuthKeys::OTP_EXPIRY]))) {
+        $otpExpiry = $user->getFieldValue($this->keyFields[AuthKeys::OTP_EXPIRY]);
+
+        if (!$otpExpiry || new DateTime() >= new DateTime($otpExpiry)) {
             throw AuthException::verificationCodeExpired();
         }
 
@@ -324,7 +308,7 @@ protected function isActivated(User $user): bool
      */
     protected function generateToken(?string $val = null): string
     {
-        return base64_encode($this->hasher->hash($val ?: config()->get('app.key')));
+        return base64_encode($this->hasher->hash($val ?: config()->get('app.key')) ?? '');
     }
 
     /**
@@ -339,7 +323,7 @@ protected function sendMail(User $user, array $body): void
         $appName = config()->get('app.name') ?: '';
 
         $this->mailer->setFrom($appEmail, $appName)
-            ->setAddress($user->getFieldValue($this->keyFields[AuthKeys::USERNAME]), $fullName)
+            ->setAddress($user->getFieldValue($this->keyFields[AuthKeys::USERNAME]) ?? '', $fullName)
             ->setBody($body)
             ->send();
     }
diff --git a/src/Cache/Adapters/DatabaseAdapter.php b/src/Cache/Adapters/DatabaseAdapter.php
index 2fc24830..555fb002 100644
--- a/src/Cache/Adapters/DatabaseAdapter.php
+++ b/src/Cache/Adapters/DatabaseAdapter.php
@@ -17,7 +17,9 @@
 namespace Quantum\Cache\Adapters;
 
 use Quantum\Cache\Enums\ExceptionMessages;
+use Quantum\App\Exceptions\BaseException;
 use Quantum\Model\Factories\ModelFactory;
+use Quantum\Cache\Traits\CacheTrait;
 use Psr\SimpleCache\CacheInterface;
 use InvalidArgumentException;
 use Quantum\Model\DbModel;
@@ -29,15 +31,7 @@
  */
 class DatabaseAdapter implements CacheInterface
 {
-    /**
-     * @var int
-     */
-    private $ttl;
-
-    /**
-     * @var string
-     */
-    private $prefix;
+    use CacheTrait;
 
     private DbModel $cacheModel;
 
@@ -53,12 +47,17 @@ public function __construct(array $params)
 
     /**
      * @inheritDoc
+     * @throws BaseException
      */
     public function get($key, $default = null)
     {
         if ($this->has($key)) {
             $cacheItem = $this->cacheModel->findOneBy('key', $this->keyHash($key));
 
+            if ($cacheItem === null) {
+                return $default;
+            }
+
             try {
                 return unserialize($cacheItem->prop('value'));
             } catch (Exception $e) {
@@ -72,14 +71,17 @@ public function get($key, $default = null)
 
     /**
      * @inheritDoc
-     * @throws InvalidArgumentException
      * @param iterable<string> $keys
      * @return iterable<string, mixed>
+     * @throws InvalidArgumentException|BaseException
      */
     public function getMultiple($keys, $default = null)
     {
         if (!is_array($keys)) {
-            throw new InvalidArgumentException(_message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$keys'), E_WARNING);
+            throw new InvalidArgumentException(
+                _message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$keys'),
+                E_WARNING
+            );
         }
 
         $result = [];
@@ -98,11 +100,11 @@ public function has($key): bool
     {
         $cacheItem = $this->cacheModel->findOneBy('key', $this->keyHash($key));
 
-        if (empty($cacheItem->asArray())) {
+        if ($cacheItem === null || empty($cacheItem->asArray())) {
             return false;
         }
 
-        if (time() - $cacheItem->prop('ttl') > $this->ttl) {
+        if (time() >= $cacheItem->prop('ttl')) {
             $this->delete($key);
             return false;
         }
@@ -117,13 +119,13 @@ public function set($key, $value, $ttl = null): bool
     {
         $cacheItem = $this->cacheModel->findOneBy('key', $this->keyHash($key));
 
-        if (empty($cacheItem->asArray())) {
+        if ($cacheItem === null || empty($cacheItem->asArray())) {
             $cacheItem = $this->cacheModel->create();
         }
 
         $cacheItem->prop('key', $this->keyHash($key));
         $cacheItem->prop('value', serialize($value));
-        $cacheItem->prop('ttl', time());
+        $cacheItem->prop('ttl', time() + $this->normalizeTtl($ttl));
 
         return $cacheItem->save();
     }
@@ -136,7 +138,10 @@ public function set($key, $value, $ttl = null): bool
     public function setMultiple($values, $ttl = null): bool
     {
         if (!is_array($values)) {
-            throw new InvalidArgumentException(_message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$values'), E_WARNING);
+            throw new InvalidArgumentException(
+                _message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$values'),
+                E_WARNING
+            );
         }
 
         $results = [];
@@ -155,7 +160,7 @@ public function delete($key): bool
     {
         $cacheItem = $this->cacheModel->findOneBy('key', $this->keyHash($key));
 
-        if (!empty($cacheItem->asArray())) {
+        if ($cacheItem !== null && !empty($cacheItem->asArray())) {
             return $cacheItem->delete();
         }
 
@@ -170,7 +175,10 @@ public function delete($key): bool
     public function deleteMultiple($keys): bool
     {
         if (!is_array($keys)) {
-            throw new InvalidArgumentException(_message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$keys'), E_WARNING);
+            throw new InvalidArgumentException(
+                _message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$keys'),
+                E_WARNING
+            );
         }
 
         $results = [];
@@ -190,11 +198,4 @@ public function clear(): bool
         return $this->cacheModel->deleteMany();
     }
 
-    /**
-     * Gets the hashed key
-     */
-    private function keyHash(string $key): string
-    {
-        return sha1($this->prefix . $key);
-    }
 }
diff --git a/src/Cache/Adapters/FileAdapter.php b/src/Cache/Adapters/FileAdapter.php
index 3a43d6d1..37525de3 100644
--- a/src/Cache/Adapters/FileAdapter.php
+++ b/src/Cache/Adapters/FileAdapter.php
@@ -22,6 +22,7 @@
 use Quantum\App\Exceptions\BaseException;
 use Quantum\Di\Exceptions\DiException;
 use Psr\SimpleCache\CacheInterface;
+use Quantum\Cache\Traits\CacheTrait;
 use Quantum\Storage\FileSystem;
 use InvalidArgumentException;
 use ReflectionException;
@@ -32,17 +33,9 @@
  */
 class FileAdapter implements CacheInterface
 {
-    private FileSystem $fs;
-
-    /**
-     * @var int
-     */
-    private $ttl;
+    use CacheTrait;
 
-    /**
-     * @var string
-     */
-    private $prefix;
+    private FileSystem $fs;
 
     /**
      * @var string
@@ -119,7 +112,7 @@ public function has($key): bool
             return false;
         }
 
-        if (time() - $this->fs->lastModified($path) > $this->ttl) {
+        if (time() >= $this->fs->lastModified($path)) {
             $this->delete($key);
             return false;
         }
@@ -130,9 +123,17 @@ public function has($key): bool
     /**
      * @inheritDoc
      */
-    public function set($key, $value, $ttl = null)
+    public function set($key, $value, $ttl = null): bool
     {
-        return $this->fs->put($this->getPath($key), serialize($value));
+        $path = $this->getPath($key);
+        $result = $this->fs->put($path, serialize($value)) !== false;
+
+        if ($result && !touch($path, time() + $this->normalizeTtl($ttl))) {
+            $this->fs->remove($path);
+            return false;
+        }
+
+        return $result;
     }
 
     /**
@@ -158,7 +159,7 @@ public function setMultiple($values, $ttl = null): bool
     /**
      * @inheritDoc
      */
-    public function delete($key)
+    public function delete($key): bool
     {
         $path = $this->getPath($key);
 
@@ -216,6 +217,6 @@ public function clear(): bool
      */
     private function getPath(string $key): string
     {
-        return $this->cacheDir . DS . sha1($this->prefix . $key);
+        return $this->cacheDir . DS . $this->keyHash($key);
     }
 }
diff --git a/src/Cache/Adapters/MemcachedAdapter.php b/src/Cache/Adapters/MemcachedAdapter.php
index f682cded..eb8a5448 100644
--- a/src/Cache/Adapters/MemcachedAdapter.php
+++ b/src/Cache/Adapters/MemcachedAdapter.php
@@ -19,6 +19,7 @@
 use Quantum\Cache\Exceptions\CacheException;
 use Quantum\Cache\Enums\ExceptionMessages;
 use Quantum\App\Exceptions\BaseException;
+use Quantum\Cache\Traits\CacheTrait;
 use Psr\SimpleCache\CacheInterface;
 use InvalidArgumentException;
 use Memcached;
@@ -30,15 +31,7 @@
  */
 class MemcachedAdapter implements CacheInterface
 {
-    /**
-     * @var int
-     */
-    private $ttl;
-
-    /**
-     * @var string
-     */
-    private $prefix;
+    use CacheTrait;
 
     private Memcached $memcached;
 
@@ -87,7 +80,10 @@ public function get($key, $default = null)
     public function getMultiple($keys, $default = null)
     {
         if (!is_array($keys)) {
-            throw new InvalidArgumentException(_message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$values'), E_WARNING);
+            throw new InvalidArgumentException(
+                _message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$keys'),
+                E_WARNING
+            );
         }
 
         $result = [];
@@ -113,7 +109,7 @@ public function has($key): bool
      */
     public function set($key, $value, $ttl = null): bool
     {
-        return $this->memcached->set($this->keyHash($key), serialize($value), $this->ttl);
+        return $this->memcached->set($this->keyHash($key), serialize($value), $this->normalizeTtl($ttl));
     }
 
     /**
@@ -124,7 +120,10 @@ public function set($key, $value, $ttl = null): bool
     public function setMultiple($values, $ttl = null): bool
     {
         if (!is_array($values)) {
-            throw new InvalidArgumentException(_message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$values'), E_WARNING);
+            throw new InvalidArgumentException(
+                _message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$values'),
+                E_WARNING
+            );
         }
 
         $results = [];
@@ -152,7 +151,10 @@ public function delete($key): bool
     public function deleteMultiple($keys): bool
     {
         if (!is_array($keys)) {
-            throw new InvalidArgumentException(_message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$values'), E_WARNING);
+            throw new InvalidArgumentException(
+                _message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$keys'),
+                E_WARNING
+            );
         }
 
         $results = [];
@@ -172,11 +174,4 @@ public function clear(): bool
         return $this->memcached->flush();
     }
 
-    /**
-     * Gets the hashed key
-     */
-    private function keyHash(string $key): string
-    {
-        return sha1($this->prefix . $key);
-    }
 }
diff --git a/src/Cache/Adapters/RedisAdapter.php b/src/Cache/Adapters/RedisAdapter.php
index c384a120..0b63ab72 100644
--- a/src/Cache/Adapters/RedisAdapter.php
+++ b/src/Cache/Adapters/RedisAdapter.php
@@ -17,6 +17,7 @@
 namespace Quantum\Cache\Adapters;
 
 use Quantum\Cache\Enums\ExceptionMessages;
+use Quantum\Cache\Traits\CacheTrait;
 use Psr\SimpleCache\CacheInterface;
 use InvalidArgumentException;
 use RedisException;
@@ -29,15 +30,7 @@
  */
 class RedisAdapter implements CacheInterface
 {
-    /**
-     * @var int
-     */
-    private $ttl;
-
-    /**
-     * @var string
-     */
-    private $prefix;
+    use CacheTrait;
 
     private Redis $redis;
 
@@ -82,7 +75,10 @@ public function get($key, $default = null)
     public function getMultiple($keys, $default = null)
     {
         if (!is_array($keys)) {
-            throw new InvalidArgumentException(_message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$values'), E_WARNING);
+            throw new InvalidArgumentException(
+                _message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$keys'),
+                E_WARNING
+            );
         }
 
         $result = [];
@@ -107,9 +103,13 @@ public function has($key): bool
      * @inheritDoc
      * @throws RedisException
      */
-    public function set($key, $value, $ttl = null)
+    public function set($key, $value, $ttl = null): bool
     {
-        return $this->redis->set($this->keyHash($key), serialize($value), $this->ttl);
+        return (bool) $this->redis->set(
+            $this->keyHash($key),
+            serialize($value),
+            $this->normalizeTtl($ttl)
+        );
     }
 
     /**
@@ -121,7 +121,10 @@ public function set($key, $value, $ttl = null)
     public function setMultiple($values, $ttl = null): bool
     {
         if (!is_array($values)) {
-            throw new InvalidArgumentException(_message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$values'), E_WARNING);
+            throw new InvalidArgumentException(
+                _message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$values'),
+                E_WARNING
+            );
         }
 
         $results = [];
@@ -149,7 +152,10 @@ public function delete($key): bool
     public function deleteMultiple($keys): bool
     {
         if (!is_array($keys)) {
-            throw new InvalidArgumentException(_message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$values'), E_WARNING);
+            throw new InvalidArgumentException(
+                _message(ExceptionMessages::ARGUMENT_NOT_ITERABLE, '$keys'),
+                E_WARNING
+            );
         }
 
         $results = [];
@@ -165,16 +171,8 @@ public function deleteMultiple($keys): bool
      * @inheritDoc
      * @throws RedisException
      */
-    public function clear()
-    {
-        return $this->redis->flushdb();
-    }
-
-    /**
-     * Gets the hashed key
-     */
-    private function keyHash(string $key): string
+    public function clear(): bool
     {
-        return sha1($this->prefix . $key);
+        return (bool) $this->redis->flushdb();
     }
 }
diff --git a/src/Cache/Factories/CacheFactory.php b/src/Cache/Factories/CacheFactory.php
index d67b5738..7f2cc130 100644
--- a/src/Cache/Factories/CacheFactory.php
+++ b/src/Cache/Factories/CacheFactory.php
@@ -24,6 +24,7 @@
 use Quantum\Cache\Adapters\RedisAdapter;
 use Quantum\Cache\Adapters\FileAdapter;
 use Quantum\Di\Exceptions\DiException;
+use Psr\SimpleCache\CacheInterface;
 use Quantum\Cache\Enums\CacheType;
 use Quantum\Loader\Setup;
 use ReflectionException;
@@ -73,9 +74,18 @@ public static function get(?string $adapter = null): Cache
         return self::$instances[$adapter];
     }
 
+    /**
+     * @throws CacheException
+     */
     private static function createInstance(string $adapterClass, string $adapter): Cache
     {
-        return new Cache(new $adapterClass(config()->get('cache.' . $adapter)));
+        $cacheAdapter = new $adapterClass(config()->get('cache.' . $adapter));
+
+        if (!$cacheAdapter instanceof CacheInterface) {
+            throw CacheException::adapterNotSupported($adapter);
+        }
+
+        return new Cache($cacheAdapter);
     }
 
     /**
diff --git a/src/Cache/Traits/CacheTrait.php b/src/Cache/Traits/CacheTrait.php
new file mode 100644
index 00000000..de64e695
--- /dev/null
+++ b/src/Cache/Traits/CacheTrait.php
@@ -0,0 +1,66 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Quantum PHP Framework
+ *
+ * An open source software development framework for PHP
+ *
+ * @package Quantum
+ * @author Arman Ag. <arman.ag@softberg.org>
+ * @copyright Copyright (c) 2018 Softberg LLC (https://softberg.org)
+ * @link http://quantum.softberg.org/
+ * @since 3.0.0
+ */
+
+namespace Quantum\Cache\Traits;
+
+use DateTimeImmutable;
+use DateInterval;
+
+/**
+ * Trait CacheTrait
+ * @package Quantum\Cache\Traits
+ */
+trait CacheTrait
+{
+    /**
+     * @var int
+     */
+    protected $ttl;
+
+    /**
+     * @var string
+     */
+    protected $prefix;
+
+    /**
+     * Gets the hashed key
+     */
+    protected function keyHash(string $key): string
+    {
+        return sha1($this->prefix . $key);
+    }
+
+    /**
+     * Normalizes the TTL
+     * @param int|DateInterval|null $ttl
+     * @return int
+     */
+    protected function normalizeTtl($ttl): int
+    {
+        if ($ttl instanceof DateInterval) {
+            $now = new DateTimeImmutable();
+            $future = $now->add($ttl);
+
+            return max(0, $future->getTimestamp() - $now->getTimestamp());
+        }
+
+        if ($ttl === null) {
+            return $this->ttl;
+        }
+
+        return (int) $ttl;
+    }
+}
diff --git a/src/Captcha/Factories/CaptchaFactory.php b/src/Captcha/Factories/CaptchaFactory.php
index ad5b8da6..751e4613 100644
--- a/src/Captcha/Factories/CaptchaFactory.php
+++ b/src/Captcha/Factories/CaptchaFactory.php
@@ -17,6 +17,7 @@
 namespace Quantum\Captcha\Factories;
 
 use Quantum\Captcha\Exceptions\CaptchaException;
+use Quantum\Captcha\Contracts\CaptchaInterface;
 use Quantum\Captcha\Adapters\RecaptchaAdapter;
 use Quantum\Config\Exceptions\ConfigException;
 use Quantum\Captcha\Adapters\HcaptchaAdapter;
@@ -70,9 +71,18 @@ public static function get(?string $adapter = null): Captcha
         return self::$instances[$adapter];
     }
 
+    /**
+     * @throws CaptchaException
+     */
     private static function createInstance(string $adapterClass, string $adapter): Captcha
     {
-        return new Captcha(new $adapterClass(config()->get('captcha.' . $adapter), new HttpClient()));
+        $adapterInstance = new $adapterClass(config()->get('captcha.' . $adapter), new HttpClient());
+
+        if (!$adapterInstance instanceof CaptchaInterface) {
+            throw CaptchaException::adapterNotSupported($adapter);
+        }
+
+        return new Captcha($adapterInstance);
     }
 
     /**
diff --git a/src/Captcha/Traits/CaptchaTrait.php b/src/Captcha/Traits/CaptchaTrait.php
index 4e2ac7de..4ebd4e15 100644
--- a/src/Captcha/Traits/CaptchaTrait.php
+++ b/src/Captcha/Traits/CaptchaTrait.php
@@ -50,7 +50,7 @@ trait CaptchaTrait
     protected array $errorCodes = [];
 
     /**
-     * @var array<string, string>
+     * @var array<int, string>
      */
     protected array $elementAttributes = [];
 
diff --git a/src/Console/Commands/DebugBarCommand.php b/src/Console/Commands/DebugBarCommand.php
index 6e0b0b40..ba501c48 100644
--- a/src/Console/Commands/DebugBarCommand.php
+++ b/src/Console/Commands/DebugBarCommand.php
@@ -18,9 +18,7 @@
 
 use Quantum\Storage\Exceptions\FileSystemException;
 use Quantum\Storage\Factories\FileSystemFactory;
-use Quantum\Config\Exceptions\ConfigException;
 use Quantum\App\Exceptions\BaseException;
-use Quantum\Di\Exceptions\DiException;
 use Quantum\Storage\FileSystem;
 use Quantum\Console\QtCommand;
 use ReflectionException;
@@ -34,7 +32,7 @@ class DebugBarCommand extends QtCommand
     /**
      * File System
      */
-    protected ?FileSystem $fs = null;
+    protected FileSystem $fs;
 
     /**
      * Command name
@@ -61,17 +59,21 @@ class DebugBarCommand extends QtCommand
      */
     private string $vendorDebugBarFolderPath = 'vendor/php-debugbar/php-debugbar/src/DebugBar/Resources';
 
+    /**
+     * @throws BaseException|ReflectionException
+     */
+    public function __construct()
+    {
+        parent::__construct();
+        $this->fs = FileSystemFactory::get();
+    }
+
     /**
      * Executes the command and publishes the debug bar assets
-     * @throws BaseException
-     * @throws FileSystemException
-     * @throws ConfigException
-     * @throws DiException
-     * @throws ReflectionException
+     * @throws FileSystemException|BaseException
      */
     public function exec(): void
     {
-        $this->fs = FileSystemFactory::get();
 
         if ($this->fs->exists(assets_dir() . DS . 'DebugBar' . DS . 'Resources' . DS . 'debugbar.css')) {
             $this->error('The debug ber already installed');
diff --git a/src/Console/Commands/InstallToolkitCommand.php b/src/Console/Commands/InstallToolkitCommand.php
index 790ed7fe..82ab3878 100644
--- a/src/Console/Commands/InstallToolkitCommand.php
+++ b/src/Console/Commands/InstallToolkitCommand.php
@@ -22,6 +22,7 @@
 use Symfony\Component\Console\Input\ArrayInput;
 use Quantum\Environment\Environment;
 use Quantum\Console\QtCommand;
+use RuntimeException;
 
 /**
  * Class InstallToolkitCommand
@@ -88,13 +89,18 @@ public function exec(): void
 
     /**
      * Runs an external command
-     * @throws ExceptionInterface
      * @param array<string, mixed> $arguments
-     * @return void
+     * @throws ExceptionInterface
      */
     protected function runExternalCommand(string $commandName, array $arguments): void
     {
-        $command = $this->getApplication()->find($commandName);
+        $application = $this->getApplication();
+
+        if ($application === null) {
+            throw new RuntimeException('Application is not set.');
+        }
+
+        $command = $application->find($commandName);
         $command->run(new ArrayInput($arguments), new NullOutput());
     }
 }
diff --git a/src/Console/Commands/KeyGenerateCommand.php b/src/Console/Commands/KeyGenerateCommand.php
index 10fe0b72..2a99090d 100644
--- a/src/Console/Commands/KeyGenerateCommand.php
+++ b/src/Console/Commands/KeyGenerateCommand.php
@@ -77,6 +77,6 @@ public function exec(): void
      */
     private function generateRandomKey(): string
     {
-        return bin2hex(random_bytes((int) $this->getOption('length')));
+        return bin2hex(random_bytes(max(1, (int) $this->getOption('length'))));
     }
 }
diff --git a/src/Console/Commands/OpenApiCommand.php b/src/Console/Commands/OpenApiCommand.php
index a9fbbff8..5df57383 100644
--- a/src/Console/Commands/OpenApiCommand.php
+++ b/src/Console/Commands/OpenApiCommand.php
@@ -130,7 +130,11 @@ public function exec(): void
         }
 
         if (!route_group_exists('openapi', $module)) {
-            $this->fs->put($routes, str_replace('return function ($route) {', $this->openapiRoutes($module), $this->fs->get($routes)));
+            $routeContent = $this->fs->get($routes);
+
+            if ($routeContent !== false) {
+                $this->fs->put($routes, str_replace('return function ($route) {', $this->openapiRoutes($module), $routeContent));
+            }
         }
 
         if (!$this->fs->isDirectory($modulePath . DS . 'resources' . DS . 'openapi')) {
@@ -169,6 +173,11 @@ private function generateOpenapiSpecification(string $module): void
 
         $openApi = Generator::scan([$annotationPath]);
 
+        if ($openApi === null) {
+            $this->error('Failed to generate OpenAPI specification.');
+            return;
+        }
+
         $this->fs->put($specPath, $openApi->toJson());
 
         $this->info('OpenAPI specification generated successfully.');
diff --git a/src/Console/Commands/ResourceCacheClearCommand.php b/src/Console/Commands/ResourceCacheClearCommand.php
index 3705fe9b..631b135f 100644
--- a/src/Console/Commands/ResourceCacheClearCommand.php
+++ b/src/Console/Commands/ResourceCacheClearCommand.php
@@ -17,6 +17,7 @@
 namespace Quantum\Console\Commands;
 
 use Quantum\Storage\Factories\FileSystemFactory;
+use Quantum\Loader\Exceptions\LoaderException;
 use Quantum\Config\Exceptions\ConfigException;
 use Quantum\App\Exceptions\BaseException;
 use Quantum\Di\Exceptions\DiException;
@@ -73,7 +74,16 @@ class ResourceCacheClearCommand extends QtCommand
 
     protected string $cacheDir = '';
 
-    protected ?FileSystem $fs = null;
+    protected FileSystem $fs;
+
+    /**
+     * @throws BaseException|ReflectionException
+     */
+    public function __construct()
+    {
+        parent::__construct();
+        $this->fs = FileSystemFactory::get();
+    }
 
     /**
      * @throws BaseException|ReflectionException
@@ -89,8 +99,6 @@ public function exec(): void
             return;
         }
 
-        $this->fs = FileSystemFactory::get();
-
         if (!$this->fs->isDirectory($this->cacheDir)) {
             $this->error('Cache directory does not exist or is not accessible.');
             return;
@@ -127,7 +135,7 @@ private function importModules(): void
     /**
      * @throws ConfigException
      * @throws DiException
-     * @throws ReflectionException
+     * @throws ReflectionException|LoaderException
      */
     private function importConfig(): void
     {
diff --git a/src/Console/Commands/RouteListCommand.php b/src/Console/Commands/RouteListCommand.php
index 2f841c52..a1db75ec 100644
--- a/src/Console/Commands/RouteListCommand.php
+++ b/src/Console/Commands/RouteListCommand.php
@@ -93,7 +93,7 @@ static function (Route $route) use ($module): bool {
                 $rows[] = $this->composeTableRow($route, 50);
             }
 
-            $table = new Table($this->output);
+            $table = new Table($this->resolveOutput());
 
             $table->setHeaderTitle('Routes')
                 ->setHeaders(['MODULE', 'METHOD', 'URI', 'ACTION', 'MIDDLEWARE'])
diff --git a/src/Console/Commands/ServeCommand.php b/src/Console/Commands/ServeCommand.php
index f30d11e3..61f5d351 100644
--- a/src/Console/Commands/ServeCommand.php
+++ b/src/Console/Commands/ServeCommand.php
@@ -229,7 +229,7 @@ protected function waitUntilServerIsReady(string $host, int $port, $process): vo
      */
     protected function waitForProcess($process): void
     {
-        while (proc_get_status($process)['running']) {
+        while (($status = proc_get_status($process)) !== false && $status['running']) {
             usleep(200_000);
         }
 
diff --git a/src/Console/QtCommand.php b/src/Console/QtCommand.php
index d78cd21b..4ec38fa0 100644
--- a/src/Console/QtCommand.php
+++ b/src/Console/QtCommand.php
@@ -23,6 +23,7 @@
 use Symfony\Component\Console\Input\InputOption;
 use Quantum\Console\Contracts\CommandInterface;
 use Symfony\Component\Console\Command\Command;
+use RuntimeException;
 
 /**
  * Class QtCommand
@@ -85,7 +86,7 @@ public function __construct()
      */
     public function getArgument(?string $key = null)
     {
-        return $this->input->getArgument($key) ?? '';
+        return $this->resolveInput()->getArgument($key ?? '') ?? '';
     }
 
     /**
@@ -94,7 +95,7 @@ public function getArgument(?string $key = null)
      */
     public function getOption(?string $key = null)
     {
-        return $this->input->getOption($key) ?? '';
+        return $this->resolveInput()->getOption($key ?? '') ?? '';
     }
 
     /**
@@ -102,7 +103,7 @@ public function getOption(?string $key = null)
      */
     public function output(string $message): void
     {
-        $this->output->writeln($message);
+        $this->resolveOutput()->writeln($message);
     }
 
     /**
@@ -110,7 +111,7 @@ public function output(string $message): void
      */
     public function info(string $message): void
     {
-        $this->output->writeln("<info>$message</info>");
+        $this->resolveOutput()->writeln("<info>$message</info>");
     }
 
     /**
@@ -118,7 +119,7 @@ public function info(string $message): void
      */
     public function comment(string $message): void
     {
-        $this->output->writeln("<comment>$message</comment>");
+        $this->resolveOutput()->writeln("<comment>$message</comment>");
     }
 
     /**
@@ -126,7 +127,7 @@ public function comment(string $message): void
      */
     public function question(string $message): void
     {
-        $this->output->writeln("<question>$message</question>");
+        $this->resolveOutput()->writeln("<question>$message</question>");
     }
 
     /**
@@ -138,7 +139,7 @@ public function confirm(string $message): bool
 
         $question = new ConfirmationQuestion($message . ' [y/N] ', false);
 
-        return (bool) $helper->ask($this->input, $this->output, $question);
+        return (bool) $helper->ask($this->resolveInput(), $this->resolveOutput(), $question);
     }
 
     /**
@@ -146,7 +147,25 @@ public function confirm(string $message): bool
      */
     public function error(string $message): void
     {
-        $this->output->writeln("<error>$message</error>");
+        $this->resolveOutput()->writeln("<error>$message</error>");
+    }
+
+    protected function resolveInput(): InputInterface
+    {
+        if ($this->input === null) {
+            throw new RuntimeException('Input is not set.');
+        }
+
+        return $this->input;
+    }
+
+    protected function resolveOutput(): OutputInterface
+    {
+        if ($this->output === null) {
+            throw new RuntimeException('Output is not set.');
+        }
+
+        return $this->output;
     }
 
     /**
diff --git a/src/Cron/CronLock.php b/src/Cron/CronLock.php
index 99e98daa..5e55841f 100644
--- a/src/Cron/CronLock.php
+++ b/src/Cron/CronLock.php
@@ -53,13 +53,15 @@ public function __construct(string $taskName, ?string $lockDirectory = null, ?in
 
     public function acquire(): bool
     {
-        $this->lockHandle = fopen($this->lockFile, 'c+');
-        if ($this->lockHandle === false) {
+        $handle = fopen($this->lockFile, 'c+');
+        if ($handle === false) {
             $this->lockHandle = null;
             $this->ownsLock = false;
             return false;
         }
 
+        $this->lockHandle = $handle;
+
         if (!flock($this->lockHandle, LOCK_EX | LOCK_NB)) {
             fclose($this->lockHandle);
             $this->lockHandle = null;
diff --git a/src/Cron/CronTask.php b/src/Cron/CronTask.php
index 33a2aa08..de942111 100644
--- a/src/Cron/CronTask.php
+++ b/src/Cron/CronTask.php
@@ -29,7 +29,7 @@ class CronTask implements CronTaskInterface
     /**
      * Cron expression instance
      */
-    private ?CronExpression $cronExpression = null;
+    private CronExpression $cronExpression;
 
     /**
      * Task name
@@ -63,7 +63,7 @@ public function __construct(string $name, string $expression, callable $callback
      */
     public function getExpression(): string
     {
-        return $this->cronExpression->getExpression();
+        return $this->cronExpression->getExpression() ?? '';
     }
 
     /**
diff --git a/src/Cron/Schedule.php b/src/Cron/Schedule.php
index f8bd068d..b4a584ba 100644
--- a/src/Cron/Schedule.php
+++ b/src/Cron/Schedule.php
@@ -350,7 +350,7 @@ public function at(string $time): self
         $minute = (int) $minute;
 
         // Replace hour and minute in existing expression
-        $parts = explode(' ', $this->expression);
+        $parts = explode(' ', $this->expression ?? '');
         $parts[0] = (string) $minute;
         $parts[1] = (string) $hour;
         $this->expression = implode(' ', $parts);
diff --git a/src/Csrf/Csrf.php b/src/Csrf/Csrf.php
index b7cb156e..e4614afe 100644
--- a/src/Csrf/Csrf.php
+++ b/src/Csrf/Csrf.php
@@ -87,7 +87,7 @@ public function generateToken(string $key): ?string
      * Checks the token
      * @throws CsrfException
      */
-    public function checkToken(?Request $request): bool
+    public function checkToken(Request $request): bool
     {
         if (!$request->has(self::TOKEN_KEY)) {
             throw CsrfException::tokenNotFound();
diff --git a/src/Database/Adapters/Idiorm/IdiormDbal.php b/src/Database/Adapters/Idiorm/IdiormDbal.php
index 7a0f384f..1106fd41 100644
--- a/src/Database/Adapters/Idiorm/IdiormDbal.php
+++ b/src/Database/Adapters/Idiorm/IdiormDbal.php
@@ -67,7 +67,7 @@ class IdiormDbal implements DbalInterface, RelationalInterface
 
     /**
      * Associated model name
-     * @var string
+     * @var string|null
      */
     private $modelName;
 
@@ -202,15 +202,18 @@ public function getTable(): string
      */
     public function getOrmModel(): ORM
     {
-        if (!$this->ormModel) {
+        $model = $this->ormModel;
+
+        if (!$model) {
             if (!self::getConnection()) {
                 throw DatabaseException::missingConfig('database');
             }
 
-            $this->ormModel = (self::$ormClass)::for_table($this->table)->use_id_column($this->idColumn);
+            $model = (self::$ormClass)::for_table($this->table)->use_id_column($this->idColumn);
+            $this->ormModel = $model;
         }
 
-        return $this->ormModel;
+        return $model;
     }
 
     /**
@@ -227,7 +230,7 @@ public function getForeignKeys(): array
      */
     public function getModelName(): string
     {
-        return $this->modelName;
+        return $this->modelName ?? '';
     }
 
     /**
diff --git a/src/Database/Adapters/Idiorm/IdiormPatch.php b/src/Database/Adapters/Idiorm/IdiormPatch.php
index fec4ca40..008635ae 100644
--- a/src/Database/Adapters/Idiorm/IdiormPatch.php
+++ b/src/Database/Adapters/Idiorm/IdiormPatch.php
@@ -25,7 +25,7 @@
  */
 class IdiormPatch extends ORM
 {
-    private ?object $ormModel = null;
+    private ?ORM $ormModel = null;
 
     private static ?IdiormPatch $instance = null;
 
@@ -44,7 +44,7 @@ public static function getInstance(): IdiormPatch
     /**
      * Set ORM Object
      */
-    public function use(object $ormModel): IdiormPatch
+    public function use(ORM $ormModel): IdiormPatch
     {
         $this->ormModel = $ormModel;
         return $this;
diff --git a/src/Database/Adapters/Idiorm/Statements/Query.php b/src/Database/Adapters/Idiorm/Statements/Query.php
index 68ce30bf..15557a98 100644
--- a/src/Database/Adapters/Idiorm/Statements/Query.php
+++ b/src/Database/Adapters/Idiorm/Statements/Query.php
@@ -17,6 +17,7 @@
 namespace Quantum\Database\Adapters\Idiorm\Statements;
 
 use Quantum\Database\Exceptions\DatabaseException;
+use PDOStatement;
 use PDOException;
 
 /**
@@ -118,8 +119,13 @@ public static function fetchColumns(string $table): array
         self::query('SELECT * FROM ' . $table);
         $statement = self::lastStatement();
 
-        for ($i = 0; $i < $statement->columnCount(); $i++) {
-            $columns[] = $statement->getColumnMeta($i)['name'];
+        if ($statement instanceof PDOStatement) {
+            for ($i = 0; $i < $statement->columnCount(); $i++) {
+                $meta = $statement->getColumnMeta($i);
+                if (is_array($meta)) {
+                    $columns[] = $meta['name'];
+                }
+            }
         }
 
         return $columns;
diff --git a/src/Database/Adapters/Idiorm/Statements/Result.php b/src/Database/Adapters/Idiorm/Statements/Result.php
index 61187cc1..01fb1071 100644
--- a/src/Database/Adapters/Idiorm/Statements/Result.php
+++ b/src/Database/Adapters/Idiorm/Statements/Result.php
@@ -32,11 +32,14 @@ trait Result
      */
     public function get(): array
     {
+        $results = $this->getOrmModel()->find_many();
+        $items = is_array($results) ? $results : iterator_to_array($results);
+
         return array_map(function ($element): object {
             $item = clone $this;
             $item->updateOrmModel($element);
             return $item;
-        }, $this->getOrmModel()->find_many());
+        }, $items);
     }
 
     /**
@@ -110,7 +113,7 @@ public function asArray(): array
      * @param array<string, mixed> $result
      * @return array<string, mixed>
      */
-    public function setHidden($result): array
+    public function setHidden(array $result): array
     {
         return array_diff_key($result, array_flip($this->hidden));
     }
diff --git a/src/Database/Adapters/Sleekdb/SleekDbal.php b/src/Database/Adapters/Sleekdb/SleekDbal.php
index 7127b7ca..9e2e6af5 100644
--- a/src/Database/Adapters/Sleekdb/SleekDbal.php
+++ b/src/Database/Adapters/Sleekdb/SleekDbal.php
@@ -56,12 +56,12 @@ class SleekDbal implements DbalInterface
     protected $modifiedFields = [];
 
     /**
-     * @var array<int, array<string, mixed>>
+     * @var array<int, array<int|string, mixed>|string>
      */
     protected array $criterias = [];
 
     /**
-     * @var array<int, array<string, mixed>>
+     * @var array<int, array<int|string, mixed>>
      */
     protected array $havings = [];
 
@@ -263,8 +263,8 @@ public function getOrmModel(): Store
      */
     public function updateOrmModel(?array $modelData): void
     {
-        $this->data = $modelData;
-        $this->modifiedFields = $modelData;
+        $this->data = $modelData ?? [];
+        $this->modifiedFields = $modelData ?? [];
         $this->isNew = false;
     }
 
@@ -292,12 +292,15 @@ public function truncate(): bool
      */
     public function getBuilder(): QueryBuilder
     {
-        if (!$this->queryBuilder) {
-            $this->queryBuilder = $this->getOrmModel()->createQueryBuilder();
+        $builder = $this->queryBuilder;
+
+        if (!$builder) {
+            $builder = $this->getOrmModel()->createQueryBuilder();
+            $this->queryBuilder = $builder;
         }
 
         if ($this->selected !== []) {
-            $this->queryBuilder->select($this->selected);
+            $builder->select($this->selected);
         }
 
         if ($this->joins !== []) {
@@ -305,30 +308,30 @@ public function getBuilder(): QueryBuilder
         }
 
         if ($this->criterias !== []) {
-            $this->queryBuilder->where($this->criterias);
+            $builder->where($this->criterias);
         }
 
         if ($this->havings !== []) {
-            $this->queryBuilder->having($this->havings);
+            $builder->having($this->havings);
         }
 
         if ($this->grouped !== []) {
-            $this->queryBuilder->groupBy($this->grouped);
+            $builder->groupBy($this->grouped);
         }
 
         if ($this->ordered !== []) {
-            $this->queryBuilder->orderBy($this->ordered);
+            $builder->orderBy($this->ordered);
         }
 
         if ($this->offset) {
-            $this->queryBuilder->skip($this->offset);
+            $builder->skip($this->offset);
         }
 
         if ($this->limit) {
-            $this->queryBuilder->limit($this->limit);
+            $builder->limit($this->limit);
         }
 
-        return $this->queryBuilder;
+        return $builder;
     }
 
     /**
@@ -345,7 +348,7 @@ public function getForeignKeys(): array
      */
     public function getModelName(): string
     {
-        return $this->modelName;
+        return $this->modelName ?? '';
     }
 
     /**
diff --git a/src/Database/Adapters/Sleekdb/Statements/Join.php b/src/Database/Adapters/Sleekdb/Statements/Join.php
index 34563cf7..f70dbfbc 100644
--- a/src/Database/Adapters/Sleekdb/Statements/Join.php
+++ b/src/Database/Adapters/Sleekdb/Statements/Join.php
@@ -23,6 +23,7 @@
 use Quantum\Database\Enums\Relation;
 use Quantum\Model\DbModel;
 use SleekDB\QueryBuilder;
+use RuntimeException;
 
 /**
  * Trait Join
@@ -50,6 +51,10 @@ public function joinTo(DbModel $model, bool $switch = true): DbalInterface
     private function applyJoins(): void
     {
         if (!empty($this->joins)) {
+            if ($this->queryBuilder === null) {
+                throw new RuntimeException('Cannot apply joins without an initialized query builder.');
+            }
+
             $this->applyJoin($this->queryBuilder, $this, $this->joins[0]);
         }
     }
@@ -64,6 +69,10 @@ private function applyJoin(QueryBuilder $queryBuilder, SleekDbal $currentItem, a
         $modelToJoin = unserialize($nextItem['model']);
         $switch = $nextItem['switch'];
 
+        if (!$modelToJoin instanceof DbModel) {
+            throw new RuntimeException('Failed to unserialize join model.');
+        }
+
         $queryBuilder->join(function ($item) use ($currentItem, $modelToJoin, $switch, $level) {
 
             $sleekModel = new self(
diff --git a/src/Database/Adapters/Sleekdb/Statements/Model.php b/src/Database/Adapters/Sleekdb/Statements/Model.php
index d752e13e..5bd430a7 100644
--- a/src/Database/Adapters/Sleekdb/Statements/Model.php
+++ b/src/Database/Adapters/Sleekdb/Statements/Model.php
@@ -100,6 +100,7 @@ public function delete(): bool
      */
     public function deleteMany(): bool
     {
-        return $this->getBuilder()->getQuery()->delete();
+        $result = $this->getBuilder()->getQuery()->delete();
+        return is_bool($result) ? $result : $result !== 0;
     }
 }
diff --git a/src/Database/Adapters/Sleekdb/Statements/Result.php b/src/Database/Adapters/Sleekdb/Statements/Result.php
index cf34687d..e1bbc70f 100644
--- a/src/Database/Adapters/Sleekdb/Statements/Result.php
+++ b/src/Database/Adapters/Sleekdb/Statements/Result.php
@@ -143,7 +143,7 @@ public function asArray(): array
      * @param array<string, mixed> $result
      * @return array<string, mixed>
      */
-    public function setHidden($result): array
+    public function setHidden(array $result): array
     {
         return array_diff_key($result, array_flip($this->hidden));
     }
diff --git a/src/Di/Di.php b/src/Di/Di.php
index f1c77d9c..03798c07 100644
--- a/src/Di/Di.php
+++ b/src/Di/Di.php
@@ -31,17 +31,17 @@
 class Di
 {
     /**
-     * @var array<class-string, class-string>
+     * @var array<string, class-string>
      */
     private static array $dependencies = [];
 
     /**
-     * @var array<class-string, object>
+     * @var array<string, object>
      */
     private static array $container = [];
 
     /**
-     * @var array<class-string, bool>
+     * @var array<string, bool>
      */
     private static array $resolving = [];
 
@@ -219,6 +219,7 @@ private static function resolve(string $abstract, array $args = [], bool $single
 
     /**
      * Instantiates the dependency
+     * @param class-string $concrete
      * @param array<mixed> $args
      * @return mixed
      * @throws ReflectionException|DiException
diff --git a/src/Di/Exceptions/DiException.php b/src/Di/Exceptions/DiException.php
index 63fe899e..034c3e45 100644
--- a/src/Di/Exceptions/DiException.php
+++ b/src/Di/Exceptions/DiException.php
@@ -68,7 +68,7 @@ public static function circularDependency(string $chain): DiException
     public static function invalidCallable(?string $entry = null): DiException
     {
         return new self(
-            _message(ExceptionMessages::INVALID_CALLABLE, [$entry]),
+            _message(ExceptionMessages::INVALID_CALLABLE, [$entry ?? '']),
             E_ERROR
         );
     }
diff --git a/src/Encryption/Adapters/AsymmetricEncryptionAdapter.php b/src/Encryption/Adapters/AsymmetricEncryptionAdapter.php
index f05b26c4..d42d0104 100644
--- a/src/Encryption/Adapters/AsymmetricEncryptionAdapter.php
+++ b/src/Encryption/Adapters/AsymmetricEncryptionAdapter.php
@@ -103,7 +103,14 @@ private function generateKeyPair(): array
         }
 
         openssl_pkey_export($resource, $privateKey);
-        $publicKey = openssl_pkey_get_details($resource)['key'];
+
+        $details = openssl_pkey_get_details($resource);
+
+        if ($details === false) {
+            throw CryptorException::missingConfig('openssl.cnf');
+        }
+
+        $publicKey = $details['key'];
 
         return [
             'private' => $privateKey,
diff --git a/src/Encryption/Adapters/SymmetricEncryptionAdapter.php b/src/Encryption/Adapters/SymmetricEncryptionAdapter.php
index 1bcdf44e..5d1aed22 100644
--- a/src/Encryption/Adapters/SymmetricEncryptionAdapter.php
+++ b/src/Encryption/Adapters/SymmetricEncryptionAdapter.php
@@ -60,6 +60,10 @@ public function encrypt(string $plain): string
 
         $encrypted = openssl_encrypt($plain, self::CIPHER_METHOD, $this->appKey, 0, $iv);
 
+        if ($encrypted === false) {
+            throw CryptorException::invalidCipher();
+        }
+
         return base64_encode(base64_encode($encrypted) . '::' . base64_encode($iv));
     }
 
@@ -82,7 +86,13 @@ public function decrypt(string $encrypted): string
         $encryptedData = base64_decode($data[0]);
         $iv = base64_decode($data[1]);
 
-        return openssl_decrypt($encryptedData, self::CIPHER_METHOD, $this->appKey, 0, $iv);
+        $decrypted = openssl_decrypt($encryptedData, self::CIPHER_METHOD, $this->appKey, 0, $iv);
+
+        if ($decrypted === false) {
+            throw CryptorException::invalidCipher();
+        }
+
+        return $decrypted;
     }
 
     /**
@@ -91,6 +101,17 @@ public function decrypt(string $encrypted): string
     private function generateIV(): string
     {
         $length = openssl_cipher_iv_length(self::CIPHER_METHOD);
-        return openssl_random_pseudo_bytes($length);
+
+        if ($length === false) {
+            throw CryptorException::invalidCipher();
+        }
+
+        $bytes = openssl_random_pseudo_bytes($length);
+
+        if ($bytes === false) {
+            throw CryptorException::invalidCipher();
+        }
+
+        return $bytes;
     }
 }
diff --git a/src/Environment/Environment.php b/src/Environment/Environment.php
index e8ef37a2..ce4afe5c 100644
--- a/src/Environment/Environment.php
+++ b/src/Environment/Environment.php
@@ -170,6 +170,11 @@ public function updateRow(string $key, ?string $value): void
 
         if ($row) {
             $envFileContent = fs()->get($envFilePath);
+
+            if (!is_string($envFileContent)) {
+                throw EnvException::fileNotFound($this->envFile);
+            }
+
             $envFileContent = preg_replace('/^' . preg_quote($row, '/') . '/m', $key . '=' . $value, $envFileContent);
 
             fs()->put($envFilePath, (string) $envFileContent);
diff --git a/src/Http/Request/HttpRequest.php b/src/Http/Request/HttpRequest.php
index 00eb292d..4369f68c 100644
--- a/src/Http/Request/HttpRequest.php
+++ b/src/Http/Request/HttpRequest.php
@@ -174,7 +174,7 @@ public static function setMethod(string $method): void
      */
     public static function isMethod(string $method): bool
     {
-        return strcasecmp($method, self::$__method) === 0;
+        return strcasecmp($method, self::$__method ?? '') === 0;
     }
 
     /**
diff --git a/src/Http/Traits/Request/Params.php b/src/Http/Traits/Request/Params.php
index c1adb1d5..6c050ce6 100644
--- a/src/Http/Traits/Request/Params.php
+++ b/src/Http/Traits/Request/Params.php
@@ -32,7 +32,7 @@ trait Params
      * Request content type
      * @var string|null
      */
-    private static $__contentType;
+    private static ?string $__contentType;
 
     /**
      * Gets the GET params.
@@ -57,7 +57,7 @@ private static function postParams(): array
             return [];
         }
 
-        return filter_input_array(INPUT_POST) ?? [];
+        return filter_input_array(INPUT_POST) ?: [];
     }
 
     /**
@@ -91,7 +91,7 @@ private static function urlEncodedParams(): array
 
         parse_str(urldecode(self::getRawInput()), $result);
 
-        return $result;
+        return $result; /** @phpstan-ignore return.type */
     }
 
     /**
@@ -119,6 +119,6 @@ private static function getRawInputParams(): array
      */
     private static function getRawInput(): string
     {
-        return file_get_contents('php://input');
+        return file_get_contents('php://input') ?: '';
     }
 }
diff --git a/src/Http/Traits/Request/RawInput.php b/src/Http/Traits/Request/RawInput.php
index 69be8b12..de81eff7 100644
--- a/src/Http/Traits/Request/RawInput.php
+++ b/src/Http/Traits/Request/RawInput.php
@@ -75,6 +75,11 @@ private static function getBoundary(): ?string
     private static function getBlocks(string $boundary, string $rawInput): array
     {
         $result = preg_split("/-+$boundary/", $rawInput);
+
+        if ($result === false) {
+            return [];
+        }
+
         array_pop($result);
 
         return $result;
@@ -105,12 +110,14 @@ private static function processBlocks(array $blocks): array
 
             switch ($type) {
                 case 'file':
-                    [$nameParam, $file] = self::getParsedFile($block);
+                    $parsed = self::getParsedFile($block);
 
-                    if (!$file) {
+                    if ($parsed === null) {
                         continue 2;
                     }
 
+                    [$nameParam, $file] = $parsed;
+
                     self::addFileToCollection($files, $nameParam, $file);
                     break;
 
@@ -174,12 +181,12 @@ private static function getParsedStream(string $block): array
     {
         preg_match('/name=\"([^\"]*)\".*stream[\n|\r]+([^\n\r].*)?$/s', $block, $match);
 
-        return [$match[1] => $match[2] ?? ''];
+        return [($match[1] ?? '') => $match[2] ?? ''];
     }
 
     /**
      * Gets the parsed file
-     * @return array<int, string|UploadedFile>|null
+     * @return array{string, UploadedFile}|null
      * @throws BaseException
      * @throws ConfigException
      * @throws DiException
@@ -271,7 +278,7 @@ private static function parseHeaders(string $rawHeaders): array
         $filename = '-unknown-';
         $contentType = ContentType::OCTET_STREAM;
 
-        $rawHeaders = preg_replace("/\r\n|\r|\n/", "\n", $rawHeaders);
+        $rawHeaders = preg_replace("/\r\n|\r|\n/", "\n", $rawHeaders) ?? $rawHeaders;
         $lines = explode("\n", $rawHeaders);
 
         foreach ($lines as $line) {
diff --git a/src/Http/Traits/Request/Url.php b/src/Http/Traits/Request/Url.php
index 62c962da..87876039 100644
--- a/src/Http/Traits/Request/Url.php
+++ b/src/Http/Traits/Request/Url.php
@@ -129,7 +129,8 @@ public static function getAllSegments(): array
             return ['zero_segment'];
         }
 
-        $segments = explode('/', trim(parse_url(self::$__uri)['path'], '/'));
+        $parsed = parse_url(self::$__uri);
+        $segments = explode('/', trim(is_array($parsed) ? ($parsed['path'] ?? '') : '', '/'));
         array_unshift($segments, 'zero_segment');
         return $segments;
     }
diff --git a/src/Http/Traits/Response/Body.php b/src/Http/Traits/Response/Body.php
index b34fe07a..b322efb5 100644
--- a/src/Http/Traits/Response/Body.php
+++ b/src/Http/Traits/Response/Body.php
@@ -198,9 +198,15 @@ private static function arrayToXML(array $arr): string
         self::composeXML($arr, $simpleXML);
 
         $dom = new DOMDocument();
-        $dom->loadXML($simpleXML->asXML());
+        $xml = $simpleXML->asXML();
+
+        if ($xml === false) {
+            return '';
+        }
+
+        $dom->loadXML($xml);
         $dom->formatOutput = true;
-        return $dom->saveXML();
+        return $dom->saveXML() ?: '';
     }
 
     /**
@@ -248,7 +254,7 @@ private static function composeXML(array $arr, SimpleXMLElement &$simpleXML): vo
      */
     private static function formatJson(): string
     {
-        return json_encode(self::all(), JSON_UNESCAPED_UNICODE);
+        return json_encode(self::all(), JSON_UNESCAPED_UNICODE) ?: '';
     }
 
     /**
diff --git a/src/HttpClient/HttpClient.php b/src/HttpClient/HttpClient.php
index 59e257b6..98431f5c 100644
--- a/src/HttpClient/HttpClient.php
+++ b/src/HttpClient/HttpClient.php
@@ -163,6 +163,8 @@ public function getData()
 
     /**
      * Checks if the request is multi cURL
+     * @phpstan-assert-if-true MultiCurl $this->client
+     * @phpstan-assert-if-false Curl $this->client
      */
     public function isMultiRequest(): bool
     {
@@ -317,10 +319,12 @@ public function __call(string $method, array $arguments): HttpClient
     }
 
     /**
-     * @throws ErrorException
+     * @throws ErrorException|BaseException
      */
     private function startSingleRequest(): void
     {
+        $this->ensureSingleRequest();
+
         $this->client->setOpt(CURLOPT_CUSTOMREQUEST, $this->method);
 
         if ($this->data) {
@@ -366,6 +370,7 @@ private function formatHeaders(CaseInsensitiveArray $headers): array
 
     /**
      * @throws BaseException
+     * @phpstan-assert Curl $this->client
      */
     private function ensureSingleRequest(): void
     {
diff --git a/src/Lang/Lang.php b/src/Lang/Lang.php
index bb817e0b..c473177f 100644
--- a/src/Lang/Lang.php
+++ b/src/Lang/Lang.php
@@ -81,7 +81,7 @@ public function load(): void
 
     /**
      * Get translation by key
-     * @param array<string, mixed>|null $params
+     * @param array<int|string, mixed>|string|null $params
      */
     public function getTranslation(string $key, $params = null): ?string
     {
diff --git a/src/Lang/Translator.php b/src/Lang/Translator.php
index 659b85f3..3d5202eb 100644
--- a/src/Lang/Translator.php
+++ b/src/Lang/Translator.php
@@ -86,6 +86,10 @@ public function loadTranslations(): void
      */
     private function loadFiles(array $files): void
     {
+        if ($this->translations === null) {
+            return;
+        }
+
         foreach ($files as $file) {
             $fileName = fs()->fileName($file);
 
@@ -97,7 +101,7 @@ private function loadFiles(array $files): void
 
     /**
      * Get translation by key
-     * @param array<string, mixed>|string|null $params
+     * @param array<int|string, mixed>|string|null $params
      */
     public function get(string $key, $params = null): string
     {
diff --git a/src/Loader/Loader.php b/src/Loader/Loader.php
index dab31beb..83eeae5f 100644
--- a/src/Loader/Loader.php
+++ b/src/Loader/Loader.php
@@ -79,7 +79,13 @@ public function set(string $property, $value): Loader
      */
     public function loadDir(string $dir): void
     {
-        foreach (glob($dir . DS . '*.php') as $filename) {
+        $files = glob($dir . DS . '*.php');
+
+        if (!is_array($files)) {
+            return;
+        }
+
+        foreach ($files as $filename) {
             require_once $filename;
         }
     }
@@ -106,7 +112,7 @@ public function fileExists(): bool
         }
 
         if ($this->hierarchical) {
-            $filePath = App::getBaseDir() . DS . 'shared' . DS . strtolower($this->pathPrefix) . DS . $this->fileName . '.php';
+            $filePath = App::getBaseDir() . DS . 'shared' . DS . strtolower($this->pathPrefix ?? '') . DS . $this->fileName . '.php';
             return file_exists($filePath);
         }
 
@@ -123,13 +129,13 @@ public function getFilePath(): string
 
         if (!file_exists($filePath)) {
             if ($this->hierarchical) {
-                $filePath = App::getBaseDir() . DS . 'shared' . DS . strtolower($this->pathPrefix) . DS . $this->fileName . '.php';
+                $filePath = App::getBaseDir() . DS . 'shared' . DS . strtolower($this->pathPrefix ?? '') . DS . $this->fileName . '.php';
 
                 if (!file_exists($filePath)) {
-                    throw new LoaderException(_message($this->exceptionMessage, $this->fileName));
+                    throw new LoaderException(_message($this->exceptionMessage, $this->fileName ?? ''));
                 }
             } else {
-                throw new LoaderException(_message($this->exceptionMessage, $this->fileName));
+                throw new LoaderException(_message($this->exceptionMessage, $this->fileName ?? ''));
             }
         }
 
diff --git a/src/Logger/Factories/LoggerFactory.php b/src/Logger/Factories/LoggerFactory.php
index 5a935a92..1feaf289 100644
--- a/src/Logger/Factories/LoggerFactory.php
+++ b/src/Logger/Factories/LoggerFactory.php
@@ -16,6 +16,7 @@
 
 namespace Quantum\Logger\Factories;
 
+use Quantum\Logger\Contracts\ReportableInterface;
 use Quantum\Logger\Exceptions\LoggerException;
 use Quantum\Config\Exceptions\ConfigException;
 use Quantum\Logger\Adapters\MessageAdapter;
@@ -84,9 +85,17 @@ public static function get(?string $adapter = null): Logger
 
     private static function createInstance(string $adapterClass, string $adapter): Logger
     {
-        return $adapter === LoggerType::MESSAGE
-            ? new Logger(new MessageAdapter())
-            : new Logger(new $adapterClass(config()->get('logging.' . $adapter)));
+        if ($adapter === LoggerType::MESSAGE) {
+            return new Logger(new MessageAdapter());
+        }
+
+        $adapterInstance = new $adapterClass(config()->get('logging.' . $adapter));
+
+        if (!$adapterInstance instanceof ReportableInterface) {
+            throw LoggerException::adapterNotSupported($adapter);
+        }
+
+        return new Logger($adapterInstance);
     }
 
     /**
diff --git a/src/Mailer/Adapters/MailgunAdapter.php b/src/Mailer/Adapters/MailgunAdapter.php
index e6c56fda..e4dccb62 100644
--- a/src/Mailer/Adapters/MailgunAdapter.php
+++ b/src/Mailer/Adapters/MailgunAdapter.php
@@ -38,6 +38,8 @@ class MailgunAdapter implements MailerInterface
 
     private string $apiUrl = 'https://api.mailgun.net/v3/';
 
+    private HttpClient $httpClient;
+
     /**
      * @var array<string, mixed>
      */
@@ -58,7 +60,7 @@ public function __construct(array $params)
     /**
      * Prepares the data
      */
-    private function prepare(): void
+    protected function prepare(): void
     {
         $this->data['from'] = $this->from['name'] . ' ' . $this->from['email'];
 
@@ -84,7 +86,7 @@ private function prepare(): void
         }
     }
 
-    private function sendEmail(): bool
+    protected function sendEmail(): bool
     {
         try {
             $this->httpClient
@@ -102,4 +104,13 @@ private function sendEmail(): bool
             return false;
         }
     }
+
+    /**
+     * @return array<string>
+     */
+    protected function getTransportErrors(): array
+    {
+        return $this->httpClient->getErrors();
+    }
+
 }
diff --git a/src/Mailer/Adapters/MandrillAdapter.php b/src/Mailer/Adapters/MandrillAdapter.php
index c75368c4..1b7c8797 100644
--- a/src/Mailer/Adapters/MandrillAdapter.php
+++ b/src/Mailer/Adapters/MandrillAdapter.php
@@ -36,6 +36,8 @@ class MandrillAdapter implements MailerInterface
 
     private string $apiUrl = 'https://mandrillapp.com/api/1.0/messages/send.json';
 
+    private HttpClient $httpClient;
+
     /**
      * @var array<string, mixed>
      */
@@ -55,7 +57,7 @@ public function __construct(array $params)
     /**
      * Prepares the data
      */
-    private function prepare(): void
+    protected function prepare(): void
     {
         $message = [];
 
@@ -84,7 +86,7 @@ private function prepare(): void
         $this->data['message'] = $message;
     }
 
-    private function sendEmail(): bool
+    protected function sendEmail(): bool
     {
         try {
             $this->httpClient
@@ -98,4 +100,12 @@ private function sendEmail(): bool
             return false;
         }
     }
+
+    /**
+     * @return array<string>
+     */
+    protected function getTransportErrors(): array
+    {
+        return $this->httpClient->getErrors();
+    }
 }
diff --git a/src/Mailer/Adapters/ResendAdapter.php b/src/Mailer/Adapters/ResendAdapter.php
index d66c7b5d..51400ae0 100644
--- a/src/Mailer/Adapters/ResendAdapter.php
+++ b/src/Mailer/Adapters/ResendAdapter.php
@@ -31,6 +31,8 @@ class ResendAdapter implements MailerInterface
 
     public string $name = 'Resend';
 
+    private HttpClient $httpClient;
+
     /**
      * @var string|null
      */
@@ -56,7 +58,7 @@ public function __construct(array $params)
     /**
      * Prepares the data
      */
-    private function prepare(): void
+    protected function prepare(): void
     {
         $fromName = $this->from['name'] ?? null;
 
@@ -81,7 +83,7 @@ private function prepare(): void
         }
     }
 
-    private function sendEmail(): bool
+    protected function sendEmail(): bool
     {
         try {
             $this->httpClient
@@ -99,4 +101,12 @@ private function sendEmail(): bool
             return false;
         }
     }
+
+    /**
+     * @return array<string>
+     */
+    protected function getTransportErrors(): array
+    {
+        return $this->httpClient->getErrors();
+    }
 }
diff --git a/src/Mailer/Adapters/SendgridAdapter.php b/src/Mailer/Adapters/SendgridAdapter.php
index 073d1850..8201d7a0 100644
--- a/src/Mailer/Adapters/SendgridAdapter.php
+++ b/src/Mailer/Adapters/SendgridAdapter.php
@@ -38,6 +38,8 @@ class SendgridAdapter implements MailerInterface
 
     private string $apiUrl = 'https://api.sendgrid.com/v3/mail/send';
 
+    private HttpClient $httpClient;
+
     /**
      * @var array<string, mixed>
      */
@@ -57,7 +59,7 @@ public function __construct(array $params)
     /**
      * Prepares the data
      */
-    public function prepare(): void
+    protected function prepare(): void
     {
         $this->data['from'] = $this->from;
 
@@ -85,7 +87,7 @@ public function prepare(): void
         }
     }
 
-    private function sendEmail(): bool
+    protected function sendEmail(): bool
     {
         try {
             $this->httpClient
@@ -103,4 +105,12 @@ private function sendEmail(): bool
             return false;
         }
     }
+
+    /**
+     * @return array<string>
+     */
+    protected function getTransportErrors(): array
+    {
+        return $this->httpClient->getErrors();
+    }
 }
diff --git a/src/Mailer/Adapters/SendinblueAdapter.php b/src/Mailer/Adapters/SendinblueAdapter.php
index 7e7c1da9..bf0e9368 100644
--- a/src/Mailer/Adapters/SendinblueAdapter.php
+++ b/src/Mailer/Adapters/SendinblueAdapter.php
@@ -38,6 +38,8 @@ class SendinblueAdapter implements MailerInterface
 
     private string $apiUrl = 'https://api.sendinblue.com/v3/smtp/email';
 
+    private HttpClient $httpClient;
+
     /**
      * @var array<string, mixed>
      */
@@ -57,7 +59,7 @@ public function __construct(array $params)
     /**
      * Prepares the data
      */
-    private function prepare(): void
+    protected function prepare(): void
     {
         $this->data['sender'] = $this->from;
         $this->data['to'] = $this->addresses;
@@ -77,7 +79,7 @@ private function prepare(): void
         }
     }
 
-    private function sendEmail(): bool
+    protected function sendEmail(): bool
     {
         try {
             $this->httpClient
@@ -96,4 +98,12 @@ private function sendEmail(): bool
             return false;
         }
     }
+
+    /**
+     * @return array<string>
+     */
+    protected function getTransportErrors(): array
+    {
+        return $this->httpClient->getErrors();
+    }
 }
diff --git a/src/Mailer/Adapters/SmtpAdapter.php b/src/Mailer/Adapters/SmtpAdapter.php
index 98648670..ba313c03 100644
--- a/src/Mailer/Adapters/SmtpAdapter.php
+++ b/src/Mailer/Adapters/SmtpAdapter.php
@@ -33,6 +33,8 @@ class SmtpAdapter implements MailerInterface
 
     public string $name = 'SMTP';
 
+    private PHPMailer $mailer;
+
     /**
      * SmtpAdapter constructor
      * @param array<string, mixed> $params
@@ -69,7 +71,7 @@ public function setReplay(string $email, ?string $name = null): SmtpAdapter
 
     /**
      * Gets "Reply-To" addresses
-     * @return array<string, mixed>
+     * @return array<int|string, mixed>
      */
     public function getReplays(): array
     {
@@ -94,7 +96,7 @@ public function setCC(string $email, ?string $name = null): SmtpAdapter
 
     /**
      * Gets "CC" addresses
-     * @return array<string, mixed>
+     * @return array<int|string, mixed>
      */
     public function getCCs(): array
     {
@@ -119,7 +121,7 @@ public function setBCC(string $email, ?string $name = null): SmtpAdapter
 
     /**
      * Get "BCC" addresses
-     * @return array<string, mixed>
+     * @return array<int|string, mixed>
      */
     public function getBCCs(): array
     {
@@ -134,13 +136,12 @@ public function getBCCs(): array
     public function setAttachment(string $attachment): SmtpAdapter
     {
         $this->attachments[] = $attachment;
-        ;
         return $this;
     }
 
     /**
      * Gets the attachments
-     * @return array<string, mixed>
+     * @return array<int|string, mixed>
      */
     public function getAttachments(): array
     {
@@ -165,13 +166,61 @@ public function setStringAttachment(string $content, string $filename): SmtpAdap
 
     /**
      * Gets the string attachments
-     * @return array<string, mixed>
+     * @return array<int|string, mixed>
      */
     public function getStringAttachments(): array
     {
         return $this->stringAttachments;
     }
 
+    /**
+     * @throws Exception
+     */
+    protected function resolveMessageId(): string
+    {
+        preg_match('/<(.*?)@/', $this->mailer->getLastMessageID(), $matches);
+        return $matches[1] ?? bin2hex(random_bytes(16));
+    }
+
+    protected function getRenderedMessage(): ?string
+    {
+        return $this->mailer->getSentMIMEMessage();
+    }
+
+    /**
+     * @throws \PHPMailer\PHPMailer\Exception
+     */
+    protected function beforeSave(): void
+    {
+        $this->mailer->preSend();
+    }
+
+    /**
+     * @return array<string>
+     */
+    protected function getTransportErrors(): array
+    {
+        $error = $this->mailer->ErrorInfo;
+        return $error !== '' ? [$error] : [];
+    }
+
+    protected function resetTransportState(): void
+    {
+        $this->replyToAddresses = [];
+        $this->ccAddresses = [];
+        $this->bccAddresses = [];
+        $this->attachments = [];
+        $this->stringAttachments = [];
+
+        $this->mailer->clearAddresses();
+        $this->mailer->clearCCs();
+        $this->mailer->clearBCCs();
+        $this->mailer->clearReplyTos();
+        $this->mailer->clearAllRecipients();
+        $this->mailer->clearAttachments();
+        $this->mailer->clearCustomHeaders();
+    }
+
     /**
      * Setups the SMTP
      * @param array<string, mixed> $params
@@ -191,7 +240,7 @@ private function setupSmtp(array $params): void
      * Prepares the data
      * @throws Exception
      */
-    private function prepare(): void
+    protected function prepare(): void
     {
         $this->mailer->setFrom($this->from['email'], $this->from['name']);
 
@@ -239,7 +288,7 @@ private function fillProperties(string $method, array $fields = []): void
     /**
      * @throws \PHPMailer\PHPMailer\Exception
      */
-    private function sendEmail(): bool
+    protected function sendEmail(): bool
     {
         return $this->mailer->send();
     }
diff --git a/src/Mailer/Contracts/MailerInterface.php b/src/Mailer/Contracts/MailerInterface.php
index b25c0c35..46e9aab9 100644
--- a/src/Mailer/Contracts/MailerInterface.php
+++ b/src/Mailer/Contracts/MailerInterface.php
@@ -40,7 +40,7 @@ public function setAddress(string $email, ?string $name = null): MailerInterface
 
     /**
      * Gets 'To' addresses
-     * @return array<string, mixed>
+     * @return array<int|string, mixed>
      */
     public function getAddresses(): array;
 
diff --git a/src/Mailer/Factories/MailerFactory.php b/src/Mailer/Factories/MailerFactory.php
index 70a43c6b..65a2d293 100644
--- a/src/Mailer/Factories/MailerFactory.php
+++ b/src/Mailer/Factories/MailerFactory.php
@@ -19,12 +19,13 @@
 use Quantum\Mailer\Adapters\SendinblueAdapter;
 use Quantum\Mailer\Exceptions\MailerException;
 use Quantum\Config\Exceptions\ConfigException;
+use Quantum\Mailer\Contracts\MailerInterface;
 use Quantum\Mailer\Adapters\MandrillAdapter;
 use Quantum\Mailer\Adapters\SendgridAdapter;
 use Quantum\Mailer\Adapters\MailgunAdapter;
+use Quantum\Mailer\Adapters\ResendAdapter;
 use Quantum\App\Exceptions\BaseException;
 use Quantum\Mailer\Adapters\SmtpAdapter;
-use Quantum\Mailer\Adapters\ResendAdapter;
 use Quantum\Di\Exceptions\DiException;
 use Quantum\Mailer\Enums\MailerType;
 use Quantum\Mailer\Mailer;
@@ -77,9 +78,18 @@ public static function get(?string $adapter = null): Mailer
         return self::$instances[$adapter];
     }
 
+    /**
+     * @throws MailerException
+     */
     private static function createInstance(string $adapterClass, string $adapter): Mailer
     {
-        return new Mailer(new $adapterClass(config()->get('mailer.' . $adapter)));
+        $adapterInstance = new $adapterClass(config()->get('mailer.' . $adapter));
+
+        if (!$adapterInstance instanceof MailerInterface) {
+            throw MailerException::adapterNotSupported($adapter);
+        }
+
+        return new Mailer($adapterInstance);
     }
 
     /**
diff --git a/src/Mailer/Traits/MailerTrait.php b/src/Mailer/Traits/MailerTrait.php
index 0f1683e5..9f8d0e0d 100644
--- a/src/Mailer/Traits/MailerTrait.php
+++ b/src/Mailer/Traits/MailerTrait.php
@@ -18,8 +18,6 @@
 
 use Quantum\Mailer\Contracts\MailerInterface;
 use Quantum\Di\Exceptions\DiException;
-use Quantum\HttpClient\HttpClient;
-use PHPMailer\PHPMailer\PHPMailer;
 use Quantum\Debugger\Debugger;
 use Quantum\Mailer\MailTrap;
 use ReflectionException;
@@ -39,7 +37,7 @@ trait MailerTrait
 
     /**
      * To addresses
-     * @var array<string, mixed>
+     * @var array<int|string, mixed>
      */
     private array $addresses = [];
 
@@ -61,40 +59,66 @@ trait MailerTrait
      */
     private ?string $templatePath = null;
 
-    protected ?HttpClient $httpClient = null;
-
-    protected ?PHPMailer $mailer = null;
-
     /**
      * Reply To addresses
-     * @var array<string, mixed>
+     * @var array<int|string, mixed>
      */
     protected array $replyToAddresses = [];
 
     /**
      * CC addresses
-     * @var array<string, mixed>
+     * @var array<int|string, mixed>
      */
     protected array $ccAddresses = [];
 
     /**
      * BCC addresses
-     * @var array<string, mixed>
+     * @var array<int|string, mixed>
      */
     protected array $bccAddresses = [];
 
     /**
      * Email attachments
-     * @var array<string, mixed>
+     * @var array<int|string, mixed>
      */
     protected array $attachments = [];
 
     /**
      * Email attachments created from string
-     * @var array<string, mixed>
+     * @var array<int|string, mixed>
      */
     protected array $stringAttachments = [];
 
+    abstract protected function prepare(): void;
+
+    abstract protected function sendEmail(): bool;
+
+    /**
+     * @return array<string>
+     */
+    abstract protected function getTransportErrors(): array;
+
+    /**
+     * @throws Exception
+     */
+    protected function resolveMessageId(): string
+    {
+        return bin2hex(random_bytes(16));
+    }
+
+    protected function getRenderedMessage(): ?string
+    {
+        return null;
+    }
+
+    protected function beforeSave(): void
+    {
+    }
+
+    protected function resetTransportState(): void
+    {
+    }
+
     /**
      * Sets the 'From' email and the name
      */
@@ -129,7 +153,7 @@ public function setAddress(string $email, ?string $name = null): MailerInterface
 
     /**
      * Gets 'To' addresses
-     * @return array<string, mixed>
+     * @return array<int|string, mixed>
      */
     public function getAddresses(): array
     {
@@ -204,8 +228,11 @@ public function send(): bool
 
         $this->resetFields();
 
-        if ($this->name !== 'SMTP' && !$sent) {
-            warning(implode(', ', $this->httpClient->getErrors()), ['tab' => Debugger::MAILS]);
+        if (!$sent) {
+            $errors = $this->getTransportErrors();
+            if (!empty($errors)) {
+                warning(implode(', ', $errors), ['tab' => Debugger::MAILS]);
+            }
         }
 
         return $sent;
@@ -221,12 +248,7 @@ public function getMessageId(): ?string
             return self::$messageId;
         }
 
-        if ($this->name == 'SMTP') {
-            preg_match('/<(.*?)@/', preg_quote($this->mailer->getLastMessageID()), $matches);
-            self::$messageId = $matches[1] ?? null;
-        } else {
-            self::$messageId = bin2hex(random_bytes(16));
-        }
+        self::$messageId = $this->resolveMessageId();
 
         return self::$messageId;
     }
@@ -237,11 +259,14 @@ public function getMessageId(): ?string
      */
     private function saveEmail(): bool
     {
-        if ($this->name == 'SMTP') {
-            $this->mailer->preSend();
+        $this->beforeSave();
+
+        $messageId = $this->getMessageId();
+        if ($messageId === null) {
+            return false;
         }
 
-        return MailTrap::getInstance()->saveMessage($this->getMessageId(), $this->getMessageContent());
+        return MailTrap::getInstance()->saveMessage($messageId, $this->getMessageContent());
     }
 
     /**
@@ -250,6 +275,7 @@ private function saveEmail(): bool
     private function createFromTemplate(): string
     {
         ob_start();
+        /** @phpstan-ignore argument.type */
         ob_implicit_flush(PHP_VERSION_ID >= 80000 ? false : 0);
 
         if (is_array($this->message)) {
@@ -258,7 +284,8 @@ private function createFromTemplate(): string
 
         require $this->templatePath . '.php';
 
-        return ob_get_clean();
+        $content = ob_get_clean();
+        return $content !== false ? $content : '';
     }
 
     /**
@@ -267,11 +294,7 @@ private function createFromTemplate(): string
      */
     private function getMessageContent(): string
     {
-        if ($this->name == 'SMTP') {
-            return $this->mailer->getSentMIMEMessage();
-        }
-
-        return $this->generateMessage();
+        return $this->getRenderedMessage() ?? $this->generateMessage();
     }
 
     /**
@@ -300,7 +323,13 @@ private function generateMessage(): string
 
         $message .= 'Content-Type: text/html; charset=UTF-8' . PHP_EOL . PHP_EOL;
 
-        return $message . ($this->message . PHP_EOL);
+        if ($this->templatePath) {
+            $body = $this->createFromTemplate();
+        } else {
+            $body = is_string($this->message) ? $this->message : '';
+        }
+
+        return $message . ($body . PHP_EOL);
     }
 
     /**
@@ -314,20 +343,6 @@ private function resetFields(): void
         $this->message = null;
         $this->templatePath = null;
 
-        if ($this->name == 'SMTP') {
-            $this->replyToAddresses = [];
-            $this->ccAddresses = [];
-            $this->bccAddresses = [];
-            $this->attachments = [];
-            $this->stringAttachments = [];
-
-            $this->mailer->clearAddresses();
-            $this->mailer->clearCCs();
-            $this->mailer->clearBCCs();
-            $this->mailer->clearReplyTos();
-            $this->mailer->clearAllRecipients();
-            $this->mailer->clearAttachments();
-            $this->mailer->clearCustomHeaders();
-        }
+        $this->resetTransportState();
     }
 }
diff --git a/src/Migration/Enums/ExceptionMessages.php b/src/Migration/Enums/ExceptionMessages.php
index abebb558..361c6f80 100644
--- a/src/Migration/Enums/ExceptionMessages.php
+++ b/src/Migration/Enums/ExceptionMessages.php
@@ -29,4 +29,6 @@ final class ExceptionMessages extends BaseExceptionMessages
     public const NOT_SUPPORTED_ACTION = 'The action `{%1}`, is not supported';
 
     public const NOTHING_TO_MIGRATE = 'Nothing to migrate';
+
+    public const INVALID_MIGRATION_CLASS = 'Migration class `{%1}` must extend QtMigration';
 }
diff --git a/src/Migration/Exceptions/MigrationException.php b/src/Migration/Exceptions/MigrationException.php
index 57e4f439..7fab5508 100644
--- a/src/Migration/Exceptions/MigrationException.php
+++ b/src/Migration/Exceptions/MigrationException.php
@@ -50,4 +50,12 @@ public static function nothingToMigrate(): self
             E_NOTICE
         );
     }
+
+    public static function invalidMigrationClass(string $className): self
+    {
+        return new self(
+            _message(ExceptionMessages::INVALID_MIGRATION_CLASS, [$className]),
+            E_ERROR
+        );
+    }
 }
diff --git a/src/Migration/MigrationManager.php b/src/Migration/MigrationManager.php
index e316dc01..34e70754 100644
--- a/src/Migration/MigrationManager.php
+++ b/src/Migration/MigrationManager.php
@@ -115,15 +115,14 @@ public function generateMigration(string $table, string $action): string
     /**
      * Applies migrations
      * @throws BaseException
-     * @throws ConfigException
      * @throws DatabaseException
-     * @throws DiException
      * @throws LangException
      * @throws MigrationException
      */
     public function applyMigrations(string $direction, ?int $step = null): ?int
     {
-        $databaseDriver = $this->db->getConfigs()['driver'];
+        $configs = $this->db->getConfigs();
+        $databaseDriver = $configs['driver'] ?? '';
 
         if (!in_array($databaseDriver, self::DRIVERS)) {
             throw MigrationException::driverNotSupported($databaseDriver);
@@ -146,7 +145,6 @@ public function applyMigrations(string $direction, ?int $step = null): ?int
     /**
      * Runs up migrations
      * @throws DatabaseException
-     * @throws LangException
      * @throws MigrationException
      */
     private function upgrade(): int
@@ -155,10 +153,13 @@ private function upgrade(): int
             $migrationTable = new MigrationTable();
             $migrationTable->up($this->tableFactory);
         }
+
         $this->prepareUpMigrations();
+
         if (empty($this->migrations)) {
             throw MigrationException::nothingToMigrate();
         }
+
         $migratedEntries = [];
         foreach ($this->migrations as $migrationFile) {
             $this->fs->require($migrationFile, true);
@@ -167,6 +168,10 @@ private function upgrade(): int
 
             $migration = new $migrationClassName();
 
+            if (!$migration instanceof QtMigration) {
+                throw MigrationException::invalidMigrationClass($migrationClassName);
+            }
+
             $migration->up($this->tableFactory);
 
             $migratedEntries[] = $migrationClassName;
@@ -178,7 +183,6 @@ private function upgrade(): int
     /**
      * Runs down migrations
      * @throws DatabaseException
-     * @throws LangException
      * @throws MigrationException
      */
     private function downgrade(?int $step): int
@@ -202,6 +206,10 @@ private function downgrade(?int $step): int
 
             $migration = new $migrationClassName();
 
+            if (!$migration instanceof QtMigration) {
+                throw MigrationException::invalidMigrationClass($migrationClassName);
+            }
+
             $migration->down($this->tableFactory);
 
             $migratedEntries[] = $migrationClassName;
@@ -222,9 +230,11 @@ private function prepareUpMigrations(): void
     {
         $migratedEntries = $this->getMigratedEntries();
         $migrationFiles = $this->getMigrationFiles();
+
         if ($migratedEntries === [] && $migrationFiles === []) {
             throw MigrationException::nothingToMigrate();
         }
+
         foreach ($migrationFiles as $timestamp => $migrationFile) {
             foreach ($migratedEntries as $migratedEntry) {
                 if (pathinfo($migrationFile, PATHINFO_FILENAME) == $migratedEntry['migration']) {
diff --git a/src/Migration/MigrationTable.php b/src/Migration/MigrationTable.php
index d225d5e6..edefeedc 100644
--- a/src/Migration/MigrationTable.php
+++ b/src/Migration/MigrationTable.php
@@ -35,7 +35,7 @@ class MigrationTable extends QtMigration
      * Creates the migrations table
      * @throws DatabaseException
      */
-    public function up(?TableFactory $tableFactory): void
+    public function up(TableFactory $tableFactory): void
     {
         $table = $tableFactory->create(self::TABLE);
         $table->addColumn('id', Type::INT, 11)->autoIncrement();
@@ -47,7 +47,7 @@ public function up(?TableFactory $tableFactory): void
      * Drops the migrations table
      * @throws DatabaseException
      */
-    public function down(?TableFactory $tableFactory): void
+    public function down(TableFactory $tableFactory): void
     {
         $tableFactory->drop(self::TABLE);
     }
diff --git a/src/Migration/QtMigration.php b/src/Migration/QtMigration.php
index 5f1e7564..1bcea4e2 100644
--- a/src/Migration/QtMigration.php
+++ b/src/Migration/QtMigration.php
@@ -26,13 +26,11 @@ abstract class QtMigration
 {
     /**
      * Upgrades with the specified migration class
-     * @return void
      */
-    abstract public function up(?TableFactory $tableFactory): void;
+    abstract public function up(TableFactory $tableFactory): void;
 
     /**
      * Downgrades with the specified migration class
-     * @return void
      */
-    abstract public function down(?TableFactory $tableFactory): void;
+    abstract public function down(TableFactory $tableFactory): void;
 }
diff --git a/src/Model/DbModel.php b/src/Model/DbModel.php
index 280cb15f..468d6fe2 100644
--- a/src/Model/DbModel.php
+++ b/src/Model/DbModel.php
@@ -130,10 +130,14 @@ public function first(): ?DbModel
      */
     public function get(): ModelCollection
     {
-        $models = array_map(
-            fn (?DbalInterface $item): ?DbModel => wrapToModel($item, static::class),
-            $this->getOrmInstance()->get()
-        );
+        $models = [];
+
+        foreach ($this->getOrmInstance()->get() as $item) {
+            $model = wrapToModel($item, static::class);
+            if ($model !== null) {
+                $models[] = $model;
+            }
+        }
 
         /** @var ModelCollection<int|string, Model> $collection */
         $collection = new ModelCollection($models);
diff --git a/src/Model/Factories/ModelFactory.php b/src/Model/Factories/ModelFactory.php
index 1924fab5..b0f75189 100644
--- a/src/Model/Factories/ModelFactory.php
+++ b/src/Model/Factories/ModelFactory.php
@@ -30,6 +30,9 @@ class ModelFactory
 {
     /**
      * Gets the Model
+     * @template T of Model
+     * @param class-string<T> $modelClass
+     * @return T
      * @throws ModelException
      */
     public static function get(string $modelClass): Model
@@ -99,12 +102,18 @@ protected static function createOrmInstance(
     ): DbalInterface {
         $ormClass = Database::getInstance()->getOrmClass();
 
-        return new $ormClass(
+        $instance = new $ormClass(
             $table,
             $modelName,
             $idColumn,
             $foreignKeys,
             $hidden
         );
+
+        if (!$instance instanceof DbalInterface) {
+            throw ModelException::notInstanceOf($ormClass, DbalInterface::class);
+        }
+
+        return $instance;
     }
 }
diff --git a/src/Model/ModelCollection.php b/src/Model/ModelCollection.php
index de755e9f..459f0aca 100644
--- a/src/Model/ModelCollection.php
+++ b/src/Model/ModelCollection.php
@@ -195,7 +195,10 @@ private function processModels(): void
     private function validateModel($model): void
     {
         if (!$model instanceof Model) {
-            throw ModelException::notInstanceOf(get_class($model), Model::class);
+            throw ModelException::notInstanceOf(
+                is_object($model) ? get_class($model) : gettype($model),
+                Model::class
+            );
         }
     }
 }
diff --git a/src/Module/Enums/ExceptionMessages.php b/src/Module/Enums/ExceptionMessages.php
index faac113c..4b582546 100644
--- a/src/Module/Enums/ExceptionMessages.php
+++ b/src/Module/Enums/ExceptionMessages.php
@@ -35,4 +35,6 @@ final class ExceptionMessages extends BaseExceptionMessages
     public const MISSING_MODULE_DIRECTORY = 'Module directory does not exist, skipping config update.';
 
     public const MODULE_ALREADY_EXISTS = 'A module or prefix named `{%1}` already exists';
+
+    public const DIRECTORY_LISTING_FAILED = 'Failed to list directory `{%1}`';
 }
diff --git a/src/Module/Exceptions/ModuleException.php b/src/Module/Exceptions/ModuleException.php
index 694dc20d..4ec477d0 100644
--- a/src/Module/Exceptions/ModuleException.php
+++ b/src/Module/Exceptions/ModuleException.php
@@ -71,4 +71,12 @@ public static function moduleAlreadyExists(string $name): self
             E_ERROR
         );
     }
+
+    public static function directoryListingFailed(string $directory): self
+    {
+        return new self(
+            _message(ExceptionMessages::DIRECTORY_LISTING_FAILED, [$directory]),
+            E_ERROR
+        );
+    }
 }
diff --git a/src/Module/ModuleManager.php b/src/Module/ModuleManager.php
index 2c002a8b..435c7da8 100644
--- a/src/Module/ModuleManager.php
+++ b/src/Module/ModuleManager.php
@@ -158,6 +158,10 @@ private function copyDirectory(string $src, string $dst, bool $processTemplates,
 
         $dir = $this->fs->listDirectory($src);
 
+        if (!is_array($dir)) {
+            throw ModuleException::directoryListingFailed($src);
+        }
+
         foreach ($dir as $file) {
             $srcPath = $file;
             $dstPath = str_replace($src, $dst, $file);
@@ -181,6 +185,11 @@ private function processTemplates(string $srcPath, string &$dstPath): void
     {
         $dstPath = str_replace('.php.tpl', '.php', $dstPath);
         $content = $this->fs->get($srcPath);
+
+        if (!is_string($content)) {
+            return;
+        }
+
         $processedContent = $this->replacePlaceholders($content);
         $this->fs->put($dstPath, $processedContent);
     }
diff --git a/src/Paginator/Traits/PaginatorTrait.php b/src/Paginator/Traits/PaginatorTrait.php
index f3264f74..00dd0c0b 100644
--- a/src/Paginator/Traits/PaginatorTrait.php
+++ b/src/Paginator/Traits/PaginatorTrait.php
@@ -220,7 +220,7 @@ protected function getUri(bool $withBaseUrl = false): string
             $url = $this->baseUrl . $routeUrl;
         }
 
-        $delimiter = strpos($url, '?') ? '&' : '?';
+        $delimiter = strpos($url ?? '', '?') !== false ? '&' : '?';
 
         return $url . $delimiter;
     }
@@ -275,7 +275,7 @@ protected function getPreviousPageItem(?string $previousPageLink): string
 
     /**
      * Get items links HTML
-     * @param array<string> $links
+     * @param array<int, string|null> $links
      */
     protected function getItemsLinks(int $startPage, int $endPage, int $currentPage, array $links): string
     {
@@ -320,7 +320,7 @@ protected function addFirstPageLink(int $startPage): string
 
     /**
      * Add last page link HTML
-     * @param array<string> $links
+     * @param array<int, string|null> $links
      */
     protected function addLastPageLink(int $endPage, int $totalPages, array $links): string
     {
diff --git a/src/Renderer/Adapters/HtmlAdapter.php b/src/Renderer/Adapters/HtmlAdapter.php
index eede5c46..1b1082c1 100644
--- a/src/Renderer/Adapters/HtmlAdapter.php
+++ b/src/Renderer/Adapters/HtmlAdapter.php
@@ -66,6 +66,7 @@ public function render(string $view, array $params = []): string
         }
 
         ob_start();
+        /** @phpstan-ignore argument.type */
         ob_implicit_flush(PHP_VERSION_ID >= 80000 ? false : 0);
 
         if ($params !== []) {
@@ -74,7 +75,9 @@ public function render(string $view, array $params = []): string
 
         require $filePath;
 
-        return ob_get_clean();
+        $content = ob_get_clean();
+
+        return $content !== false ? $content : '';
     }
 
     /**
diff --git a/src/Renderer/Adapters/TwigAdapter.php b/src/Renderer/Adapters/TwigAdapter.php
index a792c4d4..4a5a52ba 100644
--- a/src/Renderer/Adapters/TwigAdapter.php
+++ b/src/Renderer/Adapters/TwigAdapter.php
@@ -67,7 +67,7 @@ public function render(string $view, array $params = []): string
     {
         $loader = $this->getLoader($view);
 
-        $twig = new Environment($loader, $this->configs);
+        $twig = new Environment($loader, $this->configs ?? []);
 
         $this->addFunctionsToTwig($twig);
 
diff --git a/src/Renderer/Factories/RendererFactory.php b/src/Renderer/Factories/RendererFactory.php
index 17a02bb4..4112f888 100644
--- a/src/Renderer/Factories/RendererFactory.php
+++ b/src/Renderer/Factories/RendererFactory.php
@@ -16,6 +16,7 @@
 
 namespace Quantum\Renderer\Factories;
 
+use Quantum\Renderer\Contracts\TemplateRendererInterface;
 use Quantum\Renderer\Exceptions\RendererException;
 use Quantum\Config\Exceptions\ConfigException;
 use Quantum\Renderer\Adapters\HtmlAdapter;
@@ -69,9 +70,18 @@ public static function get(?string $adapter = null): Renderer
         return self::$instances[$adapter];
     }
 
+    /**
+     * @throws RendererException
+     */
     private static function createInstance(string $adapterClass, string $adapter): Renderer
     {
-        return new Renderer(new $adapterClass(config()->get('view.' . $adapter)));
+        $adapterInstance = new $adapterClass(config()->get('view.' . $adapter));
+
+        if (!$adapterInstance instanceof TemplateRendererInterface) {
+            throw RendererException::adapterNotSupported($adapter);
+        }
+
+        return new Renderer($adapterInstance);
     }
 
     /**
diff --git a/src/ResourceCache/ViewCache.php b/src/ResourceCache/ViewCache.php
index 280dc14b..35fe7551 100644
--- a/src/ResourceCache/ViewCache.php
+++ b/src/ResourceCache/ViewCache.php
@@ -103,8 +103,11 @@ public function setup(): void
     public function serveCachedView(string $uri, Response $response): bool
     {
         if ($this->isEnabled() && $this->exists($uri)) {
-            $response->html($this->get($uri));
-            return true;
+            $cachedContent = $this->get($uri);
+            if ($cachedContent !== null) {
+                $response->html($cachedContent);
+                return true;
+            }
         }
 
         return false;
@@ -141,7 +144,9 @@ public function get(string $key): ?string
             return null;
         }
 
-        return $this->fs->get($this->getCacheFile($key));
+        $content = $this->fs->get($this->getCacheFile($key));
+
+        return is_string($content) ? $content : null;
     }
 
     /**
diff --git a/src/Router/Helpers/router.php b/src/Router/Helpers/router.php
index 1cfebb4b..d2261c2a 100644
--- a/src/Router/Helpers/router.php
+++ b/src/Router/Helpers/router.php
@@ -21,7 +21,7 @@
 
 /**
  * Gets current route middlewares
- * @return array<string, mixed>|null
+ * @return array<int|string, mixed>|null
  * @throws DiException|ReflectionException
  */
 function current_middlewares(): ?array
@@ -107,7 +107,7 @@ function route_pattern(): string
     $request = Di::get(Request::class);
     $matchedRoute = $request->getMatchedRoute();
 
-    return $matchedRoute ? $matchedRoute->getRoute()->getCompiledPattern() : '';
+    return $matchedRoute ? ($matchedRoute->getRoute()->getCompiledPattern() ?? '') : '';
 }
 
 /**
@@ -143,7 +143,7 @@ function route_param(string $name)
 function route_method(): string
 {
     $request = Di::get(Request::class);
-    return $request->getMethod();
+    return $request->getMethod() ?? '';
 }
 
 /**
diff --git a/src/Router/PatternCompiler.php b/src/Router/PatternCompiler.php
index 5404429d..a7ff548b 100644
--- a/src/Router/PatternCompiler.php
+++ b/src/Router/PatternCompiler.php
@@ -49,7 +49,7 @@ public function match(Route $route, string $uri): bool
     {
         [$pattern, $segmentParams] = $this->compile($route);
 
-        $requestUri = urldecode(parse_url($uri, PHP_URL_PATH) ?? '');
+        $requestUri = urldecode(parse_url($uri, PHP_URL_PATH) ?: '');
 
         if (!preg_match('/^' . $this->escape($pattern) . '$/u', $requestUri, $matches)) {
             $this->params = [];
@@ -115,7 +115,7 @@ public function getParams(): array
      * Build the final named parameter map from regex matches and param metadata.
      *
      * @param array<int|string, string> $matches PCRE match array from preg_match (named captures)
-     * @param array<int, array{name: string, pattern: string}> $segmentParams
+     * @param list<array<string, mixed>> $segmentParams
      * @return array<string, mixed>
      */
     protected function extractParams(array $matches, array $segmentParams): array
@@ -156,7 +156,7 @@ protected function getSegmentParam(string $segment, int $index, int $lastIndex):
     /**
      * Generate the regex pattern and name for a matched parameter segment.
      * @param array<string> $match
-     * @return array<string, mixed>
+     * @return array{name: string, pattern: string}
      * @throws RouteException
      */
     protected function getParamPattern(array $match, string $expr, int $index, int $lastIndex): array
@@ -212,7 +212,7 @@ protected function getParamName(array $match, int $index): string
      * @param array<string, mixed>|list<array<string, mixed>> $params
      * @throws RouteException
      */
-    protected function checkParamName($params, string $name): void
+    protected function checkParamName(array $params, string $name): void
     {
         foreach ($params as $param) {
             if ($param['name'] === $name) {
diff --git a/src/Router/Route.php b/src/Router/Route.php
index 7be833f1..feff8681 100644
--- a/src/Router/Route.php
+++ b/src/Router/Route.php
@@ -50,7 +50,7 @@ final class Route
     protected ?string $module = null;
 
     /**
-     * @var array<string, mixed>|null
+     * @var array<int|string, mixed>|null
      */
     protected ?array $middlewares = null;
 
@@ -187,7 +187,7 @@ public function getGroup(): ?string
      */
     public function prefix(?string $prefix): self
     {
-        $this->prefix = $prefix !== '' ? trim($prefix, '/') : null;
+        $this->prefix = ($prefix !== null && $prefix !== '') ? trim($prefix, '/') : null;
         return $this;
     }
 
@@ -300,7 +300,7 @@ public function getName(): ?string
 
     /**
      * Return middleware list.
-     * @return array<string, mixed>|null
+     * @return array<int|string, mixed>|null
      */
     public function getMiddlewares(): ?array
     {
diff --git a/src/Router/RouteBuilder.php b/src/Router/RouteBuilder.php
index 5f618912..464ae1ee 100644
--- a/src/Router/RouteBuilder.php
+++ b/src/Router/RouteBuilder.php
@@ -41,7 +41,7 @@ final class RouteBuilder
     private ?string $currentGroupName = null;
 
     /**
-     * @var array<string, Route>
+     * @var array<int, Route>
      */
     private array $groupRoutes = [];
 
diff --git a/src/Router/RouteDispatcher.php b/src/Router/RouteDispatcher.php
index 0146a7f5..45038e54 100644
--- a/src/Router/RouteDispatcher.php
+++ b/src/Router/RouteDispatcher.php
@@ -57,6 +57,7 @@ public function dispatch(MatchedRoute $matched, Request $request): void
 
         $this->callHook($controller, '__before', $params);
 
+        /** @phpstan-ignore argument.type */
         $this->invoke($callable, $params);
 
         $this->callHook($controller, '__after', $params);
@@ -106,6 +107,7 @@ private function invoke(callable $callable, array $params): void
     private function callHook(object $controller, string $hook, array $params): void
     {
         if (method_exists($controller, $hook)) {
+            /** @phpstan-ignore argument.type */
             $this->invoke([$controller, $hook], $params);
         }
     }
diff --git a/src/Router/RouteFinder.php b/src/Router/RouteFinder.php
index 8bab1ef6..b7482ca3 100644
--- a/src/Router/RouteFinder.php
+++ b/src/Router/RouteFinder.php
@@ -41,8 +41,8 @@ public function __construct(RouteCollection $routes)
      */
     public function find(Request $request): ?MatchedRoute
     {
-        $method = $request->getMethod();
-        $uri = $request->getUri();
+        $method = $request->getMethod() ?? '';
+        $uri = $request->getUri() ?? '';
 
         foreach ($this->routes->all() as $route) {
             if (!$route->allowsMethod($method)) {
diff --git a/src/Session/Factories/SessionFactory.php b/src/Session/Factories/SessionFactory.php
index 39280f2e..8a104cf8 100644
--- a/src/Session/Factories/SessionFactory.php
+++ b/src/Session/Factories/SessionFactory.php
@@ -18,6 +18,7 @@
 
 use Quantum\Session\Adapters\Database\DatabaseSessionAdapter;
 use Quantum\Session\Adapters\Native\NativeSessionAdapter;
+use Quantum\Session\Contracts\SessionStorageInterface;
 use Quantum\Session\Exceptions\SessionException;
 use Quantum\Config\Exceptions\ConfigException;
 use Quantum\App\Exceptions\BaseException;
@@ -71,7 +72,13 @@ public static function get(?string $adapter = null): Session
 
     private static function createInstance(string $adapterClass, string $adapter): Session
     {
-        return new Session(new $adapterClass(config()->get('session.' . $adapter)));
+        $adapterInstance = new $adapterClass(config()->get('session.' . $adapter));
+
+        if (!$adapterInstance instanceof SessionStorageInterface) {
+            throw SessionException::adapterNotSupported($adapter);
+        }
+
+        return new Session($adapterInstance);
     }
 
     /**
diff --git a/src/Session/Traits/SessionTrait.php b/src/Session/Traits/SessionTrait.php
index 3fa3894c..789e7933 100644
--- a/src/Session/Traits/SessionTrait.php
+++ b/src/Session/Traits/SessionTrait.php
@@ -113,7 +113,9 @@ public function flush(): void
      */
     public function getId(): ?string
     {
-        return session_id();
+        $id = session_id();
+
+        return $id !== false ? $id : null;
     }
 
     /**
diff --git a/src/Storage/Adapters/Dropbox/DropboxApp.php b/src/Storage/Adapters/Dropbox/DropboxApp.php
index baecdea2..64a6f81a 100644
--- a/src/Storage/Adapters/Dropbox/DropboxApp.php
+++ b/src/Storage/Adapters/Dropbox/DropboxApp.php
@@ -219,7 +219,7 @@ public function contentRequest(string $endpoint, array $params, string $content
     {
         $headers = [
             'Authorization' => 'Bearer ' . $this->tokenService->getAccessToken(),
-            'Dropbox-API-Arg' => json_encode($params),
+            'Dropbox-API-Arg' => json_encode($params) ?: '',
             'Content-Type' => 'application/octet-stream',
         ];
 
diff --git a/src/Storage/Adapters/Local/LocalFileSystemAdapter.php b/src/Storage/Adapters/Local/LocalFileSystemAdapter.php
index b0ed88f1..15fb72bb 100644
--- a/src/Storage/Adapters/Local/LocalFileSystemAdapter.php
+++ b/src/Storage/Adapters/Local/LocalFileSystemAdapter.php
@@ -160,7 +160,11 @@ public function listDirectory(string $dirname)
         try {
             foreach (scandir($dirname) as $item) {
                 if ($item !== '.' && $item !== '..') {
-                    $entries[] = realpath($dirname . DS . $item);
+                    $resolved = realpath($dirname . DS . $item);
+
+                    if ($resolved !== false) {
+                        $entries[] = $resolved;
+                    }
                 }
             }
 
diff --git a/src/Storage/Factories/FileSystemFactory.php b/src/Storage/Factories/FileSystemFactory.php
index 270a77f7..aff8bcbc 100644
--- a/src/Storage/Factories/FileSystemFactory.php
+++ b/src/Storage/Factories/FileSystemFactory.php
@@ -19,6 +19,7 @@
 use Quantum\Storage\Adapters\GoogleDrive\GoogleDriveFileSystemAdapter;
 use Quantum\Storage\Adapters\Dropbox\DropboxFileSystemAdapter;
 use Quantum\Storage\Adapters\Local\LocalFileSystemAdapter;
+use Quantum\Storage\Contracts\FilesystemAdapterInterface;
 use Quantum\Storage\Adapters\GoogleDrive\GoogleDriveApp;
 use Quantum\Storage\Contracts\TokenServiceInterface;
 use Quantum\Storage\Exceptions\FileSystemException;
@@ -59,7 +60,7 @@ class FileSystemFactory
     ];
 
     /**
-     * @var array<string, CloudAppInterface>
+     * @var array<string, FileSystem>
      */
     private static array $instances = [];
 
@@ -94,9 +95,13 @@ public static function get(?string $adapter = null): FileSystem
      */
     private static function createInstance(string $adapterClass, string $adapter): FileSystem
     {
-        return new FileSystem(new $adapterClass(
-            self::createCloudApp($adapter)
-        ));
+        $fsAdapter = new $adapterClass(self::createCloudApp($adapter));
+
+        if (!$fsAdapter instanceof FilesystemAdapterInterface) {
+            throw FileSystemException::adapterNotSupported($adapter);
+        }
+
+        return new FileSystem($fsAdapter);
     }
 
     /**
diff --git a/src/Storage/Traits/CloudAppTrait.php b/src/Storage/Traits/CloudAppTrait.php
index 6eb77890..33635f6a 100644
--- a/src/Storage/Traits/CloudAppTrait.php
+++ b/src/Storage/Traits/CloudAppTrait.php
@@ -51,6 +51,11 @@ public function sendRequest(string $uri, $data = null, array $headers = [], stri
 
             if ($this->accessTokenNeedsRefresh($code, $responseBody)) {
                 $prevUrl = $this->httpClient->url();
+
+                if (empty($prevUrl)) {
+                    throw new Exception('Cannot retry request: original URL is not available.', E_ERROR);
+                }
+
                 $prevData = $this->httpClient->getData();
                 $prevHeaders = $this->httpClient->getRequestHeaders();
 
@@ -63,7 +68,10 @@ public function sendRequest(string $uri, $data = null, array $headers = [], stri
                 $responseBody = $this->sendRequest($prevUrl, $prevData, $prevHeaders);
 
             } else {
-                throw new Exception(json_encode($responseBody ?? $errors), E_ERROR);
+                throw new Exception(
+                    json_encode($responseBody ?? $errors) ?: '',
+                    E_ERROR
+                );
             }
         }
 
diff --git a/src/Storage/UploadedFile.php b/src/Storage/UploadedFile.php
index 86e8402b..b8313c6a 100644
--- a/src/Storage/UploadedFile.php
+++ b/src/Storage/UploadedFile.php
@@ -30,6 +30,7 @@
 use Quantum\Loader\Setup;
 use ReflectionException;
 use Gumlet\ImageResize;
+use RuntimeException;
 use Quantum\Di\Di;
 use SplFileInfo;
 use finfo;
@@ -156,7 +157,7 @@ public function setAllowedMimeTypes(array $allowedMimeTypes, bool $merge = true)
     public function getName(): string
     {
         if (!$this->name) {
-            $this->name = $this->localFileSystem->fileName($this->originalName);
+            $this->name = $this->localFileSystem->fileName($this->originalName ?? '');
         }
 
         return $this->name;
@@ -194,7 +195,7 @@ public function getRemoteFileSystem(): ?FilesystemAdapterInterface
     public function getExtension(): string
     {
         if (!$this->extension) {
-            $this->extension = strtolower($this->localFileSystem->extension($this->originalName));
+            $this->extension = strtolower($this->localFileSystem->extension($this->originalName ?? ''));
         }
 
         return $this->extension;
@@ -216,7 +217,17 @@ public function getMimeType(): string
         if (!$this->mimetype) {
             $fileInfo = new finfo(FILEINFO_MIME);
             $mimetype = $fileInfo->file($this->getPathname());
+
+            if (!is_string($mimetype)) {
+                throw new RuntimeException('Failed to determine MIME type for: ' . $this->getPathname());
+            }
+
             $mimetypeParts = preg_split('/\s*[;,]\s*/', $mimetype);
+
+            if (!is_array($mimetypeParts) || empty($mimetypeParts[0])) {
+                throw new RuntimeException('Failed to parse MIME type: ' . $mimetype);
+            }
+
             $this->mimetype = strtolower($mimetypeParts[0]);
             unset($fileInfo);
         }
@@ -229,7 +240,7 @@ public function getMimeType(): string
      */
     public function getMd5(): string
     {
-        return md5_file($this->getPathname());
+        return md5_file($this->getPathname()) ?: '';
     }
 
     /**
@@ -243,11 +254,15 @@ public function getDimensions(): array
             throw FileUploadException::fileTypeNotAllowed($this->getExtension());
         }
 
-        [$width, $height] = getimagesize($this->getPathname());
+        $size = getimagesize($this->getPathname());
+
+        if ($size === false) {
+            throw FileUploadException::fileTypeNotAllowed($this->getExtension());
+        }
 
         return [
-            'width' => $width,
-            'height' => $height,
+            'width' => $size[0],
+            'height' => $size[1],
         ];
     }
 
@@ -432,7 +447,13 @@ protected function setAllowedMimeTypesMap(array $allowedMimeTypes, bool $merge =
     protected function applyModifications(string $filePath)
     {
         $image = new ImageResize($filePath);
-        call_user_func_array([$image, $this->imageModifierFuncName], array_values($this->params));
+        $callable = [$image, $this->imageModifierFuncName ?? ''];
+
+        if (!is_callable($callable)) {
+            throw new RuntimeException('Invalid image modifier: ' . ($this->imageModifierFuncName ?? 'null'));
+        }
+
+        call_user_func_array($callable, array_values($this->params));
 
         $image->save($filePath);
     }
diff --git a/src/Tracer/ErrorHandler.php b/src/Tracer/ErrorHandler.php
index a5e9b506..0e29de98 100644
--- a/src/Tracer/ErrorHandler.php
+++ b/src/Tracer/ErrorHandler.php
@@ -157,6 +157,10 @@ private function handleWebException(Throwable $throwable): void
 
     private function logError(Throwable $e, string $errorType): void
     {
+        if ($this->logger === null) {
+            return;
+        }
+
         $logMethod = method_exists($this->logger, $errorType) ? $errorType : 'error';
 
         $this->logger->$logMethod($e->getMessage(), ['trace' => $e->getTraceAsString()]);
@@ -204,7 +208,8 @@ private function getSourceCode(string $filename, int $lineNumber, string $classN
     {
         $lineNumber--;
 
-        $start = max($lineNumber - floor(self::NUM_LINES / 2), 1);
+        $halfLines = intdiv(self::NUM_LINES, 2);
+        $start = max($lineNumber - $halfLines, 1);
 
         $adapter = fs()->getAdapter();
 
diff --git a/src/Validation/Traits/General.php b/src/Validation/Traits/General.php
index d7eec2dd..41d59e9c 100644
--- a/src/Validation/Traits/General.php
+++ b/src/Validation/Traits/General.php
@@ -57,7 +57,7 @@ protected function email($value): bool
     protected function creditCard($value): bool
     {
         $value = (string) $value;
-        $number = preg_replace('/\D/', '', $value);
+        $number = preg_replace('/\D/', '', $value) ?? '';
         $length = function_exists('mb_strlen') ? mb_strlen($number) : strlen($number);
 
         if ($length == 0) {
@@ -153,8 +153,14 @@ protected function date($value, ?string $format = null): bool
     {
         $value = (string) $value;
         if (!$format) {
-            $cdate1 = date('Y-m-d', strtotime($value));
-            $cdate2 = date('Y-m-d H:i:s', strtotime($value));
+            $timestamp = strtotime($value);
+
+            if ($timestamp === false) {
+                return false;
+            }
+
+            $cdate1 = date('Y-m-d', $timestamp);
+            $cdate2 = date('Y-m-d H:i:s', $timestamp);
 
             return $cdate1 === $value || $cdate2 === $value;
         }
@@ -211,11 +217,11 @@ protected function same($value, string $otherField): bool
     protected function unique($value, string $className, string $columnName): bool
     {
         /** @var DbModel $model */
-        $model = ModelFactory::get(ucfirst($className));
+        $model = ModelFactory::get(ucfirst($className)); /** @phpstan-ignore argument.type, argument.templateType */
 
         $record = $model->findOneBy($columnName, $value);
 
-        return $record->isEmpty();
+        return $record === null || $record->isEmpty();
     }
 
     /**
@@ -227,11 +233,11 @@ protected function unique($value, string $className, string $columnName): bool
     protected function exists($value, string $className, string $columnName): bool
     {
         /** @var DbModel $model */
-        $model = ModelFactory::get(ucfirst($className));
+        $model = ModelFactory::get(ucfirst($className)); /** @phpstan-ignore argument.type, argument.templateType */
 
         $record = $model->findOneBy($columnName, $value);
 
-        return !$record->isEmpty();
+        return $record !== null && !$record->isEmpty();
     }
 
     /**
diff --git a/src/Validation/Traits/Resource.php b/src/Validation/Traits/Resource.php
index 05caae17..19f50017 100644
--- a/src/Validation/Traits/Resource.php
+++ b/src/Validation/Traits/Resource.php
@@ -46,7 +46,8 @@ protected function urlExists(string $value): bool
         }
 
         if (function_exists('checkdnsrr') && function_exists('idn_to_ascii')) {
-            return checkdnsrr(idn_to_ascii($host, 0, INTL_IDNA_VARIANT_UTS46), 'A');
+            $ascii = idn_to_ascii($host, 0, INTL_IDNA_VARIANT_UTS46);
+            return $ascii !== false && checkdnsrr($ascii, 'A');
         } else {
             return gethostbyname($host) !== $host;
         }
diff --git a/src/Validation/Validator.php b/src/Validation/Validator.php
index a458405e..94df7b62 100644
--- a/src/Validation/Validator.php
+++ b/src/Validation/Validator.php
@@ -74,7 +74,7 @@ class Validator
     public function setRule(string $field, array $rules): void
     {
         foreach ($rules as $rule) {
-            $ruleName = key($rule);
+            $ruleName = (string) key($rule);
             $ruleParam = current($rule);
             $this->setOrUpdateRule($field, $ruleName, $ruleParam);
         }
@@ -97,7 +97,7 @@ public function setRules(array $rules): void
      */
     public function updateRule(string $field, array $rule): void
     {
-        $ruleName = key($rule);
+        $ruleName = (string) key($rule);
         $ruleParam = current($rule);
         $this->setOrUpdateRule($field, $ruleName, $ruleParam);
     }
diff --git a/src/View/QtView.php b/src/View/QtView.php
index c787cb13..03062677 100644
--- a/src/View/QtView.php
+++ b/src/View/QtView.php
@@ -173,7 +173,9 @@ public function flushParams(): void
      */
     public function render(string $viewFile, array $params = []): ?string
     {
-        if (!$this->layoutFile) {
+        $layoutFile = $this->layoutFile;
+
+        if (!$layoutFile) {
             throw ViewException::noLayoutSet();
         }
 
@@ -191,12 +193,15 @@ public function render(string $viewFile, array $params = []): ?string
             $this->updateDebugger($viewFile);
         }
 
-        $layoutContent = $this->renderFile($this->layoutFile);
+        $layoutContent = $this->renderFile($layoutFile);
 
         if ($this->viewCache->isEnabled()) {
-            $layoutContent = $this->viewCache
-                ->set(route_uri(), $layoutContent)
-                ->get(route_uri());
+            $uri = route_uri();
+            if ($uri !== null) {
+                $layoutContent = $this->viewCache
+                    ->set($uri, $layoutContent)
+                    ->get($uri);
+            }
         }
 
         return $layoutContent;
@@ -277,6 +282,10 @@ private function sanitizeHtml(string $value): string
         return htmlspecialchars($value, ENT_QUOTES | ENT_SUBSTITUTE, 'UTF-8');
     }
 
+    /**
+     * @throws ReflectionException
+     * @throws DiException
+     */
     private function updateDebugger(string $viewFile): void
     {
         $routesCell = $this->debugger->getStoreCell(Debugger::ROUTES);
diff --git a/tests/Unit/Cache/Adapters/DatabaseAdapterTest.php b/tests/Unit/Cache/Adapters/DatabaseAdapterTest.php
index 473425a8..8b1bf132 100644
--- a/tests/Unit/Cache/Adapters/DatabaseAdapterTest.php
+++ b/tests/Unit/Cache/Adapters/DatabaseAdapterTest.php
@@ -6,6 +6,7 @@
 use Quantum\Cache\Adapters\DatabaseAdapter;
 use Quantum\Tests\Unit\AppTestCase;
 use Quantum\Loader\Setup;
+use DateInterval;
 
 class DatabaseAdapterTest extends AppTestCase
 {
@@ -161,4 +162,42 @@ public function testDatabaseAdapterExpired(): void
         $this->assertNull($databaseCache->get('test'));
     }
 
+    public function testDatabaseAdapterSetWithCustomTtl(): void
+    {
+        $this->databaseCache->set('test', 'Test value', 120);
+
+        $this->assertTrue($this->databaseCache->has('test'));
+
+        $this->assertEquals('Test value', $this->databaseCache->get('test'));
+    }
+
+    public function testDatabaseAdapterSetWithDateIntervalTtl(): void
+    {
+        $this->databaseCache->set('test', 'Test value', new DateInterval('PT60S'));
+
+        $this->assertTrue($this->databaseCache->has('test'));
+
+        $this->assertEquals('Test value', $this->databaseCache->get('test'));
+    }
+
+    public function testDatabaseAdapterExpiredWithCustomTtl(): void
+    {
+        $this->databaseCache->set('test', 'Test value', -1);
+
+        $this->assertNull($this->databaseCache->get('test'));
+    }
+
+    public function testDatabaseAdapterPerKeyTtlIndependence(): void
+    {
+        $this->databaseCache->set('short', 'Short TTL', -1);
+
+        $this->databaseCache->set('long', 'Long TTL', 120);
+
+        $this->assertFalse($this->databaseCache->has('short'));
+
+        $this->assertTrue($this->databaseCache->has('long'));
+
+        $this->assertEquals('Long TTL', $this->databaseCache->get('long'));
+    }
+
 }
diff --git a/tests/Unit/Cache/Adapters/FileAdapterTest.php b/tests/Unit/Cache/Adapters/FileAdapterTest.php
index 04bb355d..5c3ae43b 100644
--- a/tests/Unit/Cache/Adapters/FileAdapterTest.php
+++ b/tests/Unit/Cache/Adapters/FileAdapterTest.php
@@ -4,6 +4,7 @@
 
 use Quantum\Cache\Adapters\FileAdapter;
 use Quantum\Tests\Unit\AppTestCase;
+use DateInterval;
 
 class FileAdapterTest extends AppTestCase
 {
@@ -138,4 +139,42 @@ public function testFileAdapterExpired(): void
         $this->assertNull($fileCache->get('test'));
     }
 
+    public function testFileAdapterSetWithCustomTtl(): void
+    {
+        $this->fileCache->set('test', 'Test value', 120);
+
+        $this->assertTrue($this->fileCache->has('test'));
+
+        $this->assertEquals('Test value', $this->fileCache->get('test'));
+    }
+
+    public function testFileAdapterSetWithDateIntervalTtl(): void
+    {
+        $this->fileCache->set('test', 'Test value', new DateInterval('PT60S'));
+
+        $this->assertTrue($this->fileCache->has('test'));
+
+        $this->assertEquals('Test value', $this->fileCache->get('test'));
+    }
+
+    public function testFileAdapterExpiredWithCustomTtl(): void
+    {
+        $this->fileCache->set('test', 'Test value', -1);
+
+        $this->assertNull($this->fileCache->get('test'));
+    }
+
+    public function testFileAdapterPerKeyTtlIndependence(): void
+    {
+        $this->fileCache->set('short', 'Short TTL', -1);
+
+        $this->fileCache->set('long', 'Long TTL', 120);
+
+        $this->assertFalse($this->fileCache->has('short'));
+
+        $this->assertTrue($this->fileCache->has('long'));
+
+        $this->assertEquals('Long TTL', $this->fileCache->get('long'));
+    }
+
 }
diff --git a/tests/Unit/Cache/Adapters/MemcachedAdapterTest.php b/tests/Unit/Cache/Adapters/MemcachedAdapterTest.php
index 5d17901d..fd63e842 100644
--- a/tests/Unit/Cache/Adapters/MemcachedAdapterTest.php
+++ b/tests/Unit/Cache/Adapters/MemcachedAdapterTest.php
@@ -4,6 +4,7 @@
 
 use Quantum\Cache\Adapters\MemcachedAdapter;
 use Quantum\Tests\Unit\AppTestCase;
+use DateInterval;
 
 class MemcachedAdapterTest extends AppTestCase
 {
@@ -153,4 +154,31 @@ public function testMemcachedAdapterExpired(): void
         $this->assertNull($memCached->get('test'));
     }
 
+    public function testMemcachedAdapterSetWithCustomTtl(): void
+    {
+        $this->memCached->set('test', 'Test value', 120);
+
+        $this->assertTrue($this->memCached->has('test'));
+
+        $this->assertEquals('Test value', $this->memCached->get('test'));
+    }
+
+    public function testMemcachedAdapterSetWithDateIntervalTtl(): void
+    {
+        $this->memCached->set('test', 'Test value', new DateInterval('PT60S'));
+
+        $this->assertTrue($this->memCached->has('test'));
+
+        $this->assertEquals('Test value', $this->memCached->get('test'));
+    }
+
+    public function testMemcachedAdapterExpiredWithCustomTtl(): void
+    {
+        $this->memCached->set('test', 'Test value', 1);
+
+        sleep(2);
+
+        $this->assertNull($this->memCached->get('test'));
+    }
+
 }
diff --git a/tests/Unit/Cache/Adapters/RedisAdapterTest.php b/tests/Unit/Cache/Adapters/RedisAdapterTest.php
index 79c69977..f944ab62 100644
--- a/tests/Unit/Cache/Adapters/RedisAdapterTest.php
+++ b/tests/Unit/Cache/Adapters/RedisAdapterTest.php
@@ -4,6 +4,7 @@
 
 use Quantum\Cache\Adapters\RedisAdapter;
 use Quantum\Tests\Unit\AppTestCase;
+use DateInterval;
 
 class RedisAdapterTest extends AppTestCase
 {
@@ -153,4 +154,31 @@ public function testRedisAdapterExpired(): void
         $this->assertNull($redis->get('test'));
     }
 
+    public function testRedisAdapterSetWithCustomTtl(): void
+    {
+        $this->redis->set('test', 'Test value', 120);
+
+        $this->assertTrue($this->redis->has('test'));
+
+        $this->assertEquals('Test value', $this->redis->get('test'));
+    }
+
+    public function testRedisAdapterSetWithDateIntervalTtl(): void
+    {
+        $this->redis->set('test', 'Test value', new DateInterval('PT60S'));
+
+        $this->assertTrue($this->redis->has('test'));
+
+        $this->assertEquals('Test value', $this->redis->get('test'));
+    }
+
+    public function testRedisAdapterExpiredWithCustomTtl(): void
+    {
+        $this->redis->set('test', 'Test value', 1);
+
+        sleep(2);
+
+        $this->assertNull($this->redis->get('test'));
+    }
+
 }
diff --git a/tests/Unit/Console/Commands/DebugBarCommandTest.php b/tests/Unit/Console/Commands/DebugBarCommandTest.php
new file mode 100644
index 00000000..44f7a28e
--- /dev/null
+++ b/tests/Unit/Console/Commands/DebugBarCommandTest.php
@@ -0,0 +1,53 @@
+<?php
+
+namespace Quantum\Tests\Unit\Console\Commands;
+
+use Symfony\Component\Console\Tester\CommandTester;
+use Quantum\Console\Commands\DebugBarCommand;
+use Quantum\Storage\FileSystem;
+use Quantum\Tests\Unit\AppTestCase;
+
+class DebugBarCommandTest extends AppTestCase
+{
+    private DebugBarCommand $command;
+
+    private CommandTester $tester;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->command = new DebugBarCommand();
+        $this->tester = new CommandTester($this->command);
+    }
+
+    public function testCommandMetadata(): void
+    {
+        $this->assertSame('install:debugbar', $this->command->getName());
+        $this->assertSame('Publishes debugbar assets', $this->command->getDescription());
+        $this->assertSame('The command will publish debugbar assets', $this->command->getHelp());
+    }
+
+    public function testConstructorInitializesFileSystem(): void
+    {
+        $fs = $this->getPrivateProperty($this->command, 'fs');
+        $this->assertInstanceOf(FileSystem::class, $fs);
+    }
+
+    public function testExecShowsErrorWhenAlreadyInstalled(): void
+    {
+        $assetsPath = assets_dir() . DS . 'DebugBar' . DS . 'Resources';
+
+        mkdir($assetsPath, 0777, true);
+        file_put_contents($assetsPath . DS . 'debugbar.css', '/* stub */');
+
+        $this->tester->execute([]);
+
+        $output = $this->tester->getDisplay();
+        $this->assertStringContainsString('already installed', $output);
+
+        @unlink($assetsPath . DS . 'debugbar.css');
+        @rmdir($assetsPath);
+        @rmdir(assets_dir() . DS . 'DebugBar');
+    }
+}
diff --git a/tests/Unit/Console/Commands/EnvCommandTest.php b/tests/Unit/Console/Commands/EnvCommandTest.php
new file mode 100644
index 00000000..6fc9979b
--- /dev/null
+++ b/tests/Unit/Console/Commands/EnvCommandTest.php
@@ -0,0 +1,51 @@
+<?php
+
+namespace Quantum\Tests\Unit\Console\Commands;
+
+use Symfony\Component\Console\Tester\CommandTester;
+use Quantum\Console\Commands\EnvCommand;
+use Quantum\Tests\Unit\AppTestCase;
+
+class EnvCommandTest extends AppTestCase
+{
+    private EnvCommand $command;
+
+    private CommandTester $tester;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->command = new EnvCommand();
+        $this->tester = new CommandTester($this->command);
+    }
+
+    public function testCommandMetadata(): void
+    {
+        $this->assertSame('core:env', $this->command->getName());
+        $this->assertSame('Generates new .env file', $this->command->getDescription());
+        $this->assertSame('The command will generate new .env file from .env.example', $this->command->getHelp());
+    }
+
+    public function testExecShowsErrorWhenEnvExampleMissing(): void
+    {
+        $envExample = base_dir() . DS . '.env.example';
+        $backup = $envExample . '.' . uniqid('bak', true);
+        $existed = file_exists($envExample);
+
+        if ($existed) {
+            rename($envExample, $backup);
+        }
+
+        try {
+            $this->tester->execute([]);
+
+            $output = $this->tester->getDisplay();
+            $this->assertStringContainsString('.env.example file not found', $output);
+        } finally {
+            if ($existed && file_exists($backup)) {
+                rename($backup, $envExample);
+            }
+        }
+    }
+}
diff --git a/tests/Unit/Console/Commands/InstallToolkitCommandTest.php b/tests/Unit/Console/Commands/InstallToolkitCommandTest.php
new file mode 100644
index 00000000..6f94c754
--- /dev/null
+++ b/tests/Unit/Console/Commands/InstallToolkitCommandTest.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Quantum\Tests\Unit\Console\Commands;
+
+use Quantum\Console\Commands\InstallToolkitCommand;
+use Quantum\Tests\Unit\AppTestCase;
+
+class InstallToolkitCommandTest extends AppTestCase
+{
+    private InstallToolkitCommand $command;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->command = new InstallToolkitCommand();
+    }
+
+    public function testCommandMetadata(): void
+    {
+        $this->assertSame('install:toolkit', $this->command->getName());
+        $this->assertSame('Installs toolkit', $this->command->getDescription());
+        $this->assertSame('The command will install Toolkit and its assets into your project', $this->command->getHelp());
+    }
+
+    public function testCommandArgumentsAreRegistered(): void
+    {
+        $definition = $this->command->getDefinition();
+
+        $this->assertTrue($definition->hasArgument('username'));
+        $this->assertTrue($definition->hasArgument('password'));
+        $this->assertTrue($definition->getArgument('username')->isRequired());
+        $this->assertTrue($definition->getArgument('password')->isRequired());
+    }
+}
diff --git a/tests/Unit/Console/Commands/KeyGenerateCommandTest.php b/tests/Unit/Console/Commands/KeyGenerateCommandTest.php
new file mode 100644
index 00000000..ca9c58cd
--- /dev/null
+++ b/tests/Unit/Console/Commands/KeyGenerateCommandTest.php
@@ -0,0 +1,81 @@
+<?php
+
+namespace Quantum\Tests\Unit\Console\Commands;
+
+use Symfony\Component\Console\Helper\QuestionHelper;
+use Symfony\Component\Console\Tester\CommandTester;
+use Symfony\Component\Console\Helper\HelperSet;
+use Quantum\Console\Commands\KeyGenerateCommand;
+use Quantum\Environment\Environment;
+use Quantum\Tests\Unit\AppTestCase;
+use Quantum\App\App;
+
+class KeyGenerateCommandTest extends AppTestCase
+{
+    private KeyGenerateCommand $command;
+
+    private CommandTester $tester;
+
+    private string $envFilePath;
+
+    private string $originalFileContent;
+
+    /** @var array<string, mixed> */
+    private array $originalEnvData;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->envFilePath = App::getBaseDir() . DS . '.env.testing';
+        $this->originalFileContent = (string) $this->fs->get($this->envFilePath);
+        $this->originalEnvData = $this->getPrivateProperty(Environment::getInstance(), 'envContent');
+
+        $this->command = new KeyGenerateCommand();
+        $this->command->setHelperSet(new HelperSet(['question' => new QuestionHelper()]));
+        $this->tester = new CommandTester($this->command);
+    }
+
+    public function tearDown(): void
+    {
+        $this->fs->put($this->envFilePath, $this->originalFileContent);
+        $this->setPrivateProperty(Environment::getInstance(), 'envContent', $this->originalEnvData);
+
+        parent::tearDown();
+    }
+
+    public function testCommandMetadata(): void
+    {
+        $this->assertSame('core:key', $this->command->getName());
+        $this->assertSame('Generates and stores the application key', $this->command->getDescription());
+        $this->assertSame('The command will generate APP_KEY and store in .env file', $this->command->getHelp());
+    }
+
+    public function testCommandOptionsAreRegistered(): void
+    {
+        $definition = $this->command->getDefinition();
+
+        $this->assertTrue($definition->hasOption('length'));
+        $this->assertTrue($definition->hasOption('yes'));
+    }
+
+    public function testExecGeneratesKey(): void
+    {
+        $this->tester->execute(['--yes' => true, '--length' => 16]);
+
+        $output = $this->tester->getDisplay();
+        $this->assertStringContainsString('Application key successfully generated', $output);
+        $this->assertNotEmpty(env('APP_KEY'));
+    }
+
+    public function testExecCancelsWhenNotConfirmed(): void
+    {
+        env('APP_KEY', 'existing-key');
+
+        $this->tester->setInputs(['n']);
+        $this->tester->execute([]);
+
+        $output = $this->tester->getDisplay();
+        $this->assertStringContainsString('Operation was canceled', $output);
+    }
+}
diff --git a/tests/Unit/Console/Commands/MigrationGenerateCommandTest.php b/tests/Unit/Console/Commands/MigrationGenerateCommandTest.php
new file mode 100644
index 00000000..09166e0d
--- /dev/null
+++ b/tests/Unit/Console/Commands/MigrationGenerateCommandTest.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace Quantum\Tests\Unit\Console\Commands;
+
+use Quantum\Console\Commands\MigrationGenerateCommand;
+use Quantum\Tests\Unit\AppTestCase;
+
+class MigrationGenerateCommandTest extends AppTestCase
+{
+    private MigrationGenerateCommand $command;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->command = new MigrationGenerateCommand();
+    }
+
+    public function testCommandMetadata(): void
+    {
+        $this->assertSame('migration:generate', $this->command->getName());
+        $this->assertSame('Generates new migration file', $this->command->getDescription());
+    }
+
+    public function testCommandArgumentsAreRegistered(): void
+    {
+        $definition = $this->command->getDefinition();
+
+        $this->assertTrue($definition->hasArgument('action'));
+        $this->assertTrue($definition->hasArgument('table'));
+        $this->assertTrue($definition->getArgument('action')->isRequired());
+        $this->assertTrue($definition->getArgument('table')->isRequired());
+    }
+}
diff --git a/tests/Unit/Console/Commands/MigrationMigrateCommandTest.php b/tests/Unit/Console/Commands/MigrationMigrateCommandTest.php
new file mode 100644
index 00000000..bf943bf0
--- /dev/null
+++ b/tests/Unit/Console/Commands/MigrationMigrateCommandTest.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace Quantum\Tests\Unit\Console\Commands;
+
+use Quantum\Console\Commands\MigrationMigrateCommand;
+use Quantum\Tests\Unit\AppTestCase;
+
+class MigrationMigrateCommandTest extends AppTestCase
+{
+    private MigrationMigrateCommand $command;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->command = new MigrationMigrateCommand();
+    }
+
+    public function testCommandMetadata(): void
+    {
+        $this->assertSame('migration:migrate', $this->command->getName());
+        $this->assertSame('Migrates the migrations', $this->command->getDescription());
+    }
+
+    public function testCommandArgumentsAndOptionsAreRegistered(): void
+    {
+        $definition = $this->command->getDefinition();
+
+        $this->assertTrue($definition->hasArgument('direction'));
+        $this->assertFalse($definition->getArgument('direction')->isRequired());
+
+        $this->assertTrue($definition->hasOption('step'));
+    }
+}
diff --git a/tests/Unit/Console/Commands/ModuleGenerateCommandTest.php b/tests/Unit/Console/Commands/ModuleGenerateCommandTest.php
new file mode 100644
index 00000000..0aace025
--- /dev/null
+++ b/tests/Unit/Console/Commands/ModuleGenerateCommandTest.php
@@ -0,0 +1,37 @@
+<?php
+
+namespace Quantum\Tests\Unit\Console\Commands;
+
+use Quantum\Console\Commands\ModuleGenerateCommand;
+use Quantum\Tests\Unit\AppTestCase;
+
+class ModuleGenerateCommandTest extends AppTestCase
+{
+    private ModuleGenerateCommand $command;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->command = new ModuleGenerateCommand();
+    }
+
+    public function testCommandMetadata(): void
+    {
+        $this->assertSame('module:generate', $this->command->getName());
+        $this->assertSame('Generate new module', $this->command->getDescription());
+        $this->assertSame('The command will create files for new module', $this->command->getHelp());
+    }
+
+    public function testCommandArgumentsAndOptionsAreRegistered(): void
+    {
+        $definition = $this->command->getDefinition();
+
+        $this->assertTrue($definition->hasArgument('module'));
+        $this->assertTrue($definition->getArgument('module')->isRequired());
+
+        $this->assertTrue($definition->hasOption('yes'));
+        $this->assertTrue($definition->hasOption('template'));
+        $this->assertTrue($definition->hasOption('with-assets'));
+    }
+}
diff --git a/tests/Unit/Console/Commands/OpenApiCommandTest.php b/tests/Unit/Console/Commands/OpenApiCommandTest.php
new file mode 100644
index 00000000..a3327166
--- /dev/null
+++ b/tests/Unit/Console/Commands/OpenApiCommandTest.php
@@ -0,0 +1,40 @@
+<?php
+
+namespace Quantum\Tests\Unit\Console\Commands;
+
+use Quantum\Console\Commands\OpenApiCommand;
+use Quantum\Storage\FileSystem;
+use Quantum\Tests\Unit\AppTestCase;
+
+class OpenApiCommandTest extends AppTestCase
+{
+    private OpenApiCommand $command;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->command = new OpenApiCommand();
+    }
+
+    public function testCommandMetadata(): void
+    {
+        $this->assertSame('install:openapi', $this->command->getName());
+        $this->assertSame('Generates files for OpenApi UI', $this->command->getDescription());
+        $this->assertSame('The command will publish OpenApi UI resources', $this->command->getHelp());
+    }
+
+    public function testCommandArgumentsAreRegistered(): void
+    {
+        $definition = $this->command->getDefinition();
+
+        $this->assertTrue($definition->hasArgument('module'));
+        $this->assertTrue($definition->getArgument('module')->isRequired());
+    }
+
+    public function testConstructorInitializesFileSystem(): void
+    {
+        $fs = $this->getPrivateProperty($this->command, 'fs');
+        $this->assertInstanceOf(FileSystem::class, $fs);
+    }
+}
diff --git a/tests/Unit/Console/Commands/ResourceCacheClearCommandTest.php b/tests/Unit/Console/Commands/ResourceCacheClearCommandTest.php
new file mode 100644
index 00000000..1f672a2d
--- /dev/null
+++ b/tests/Unit/Console/Commands/ResourceCacheClearCommandTest.php
@@ -0,0 +1,62 @@
+<?php
+
+namespace Quantum\Tests\Unit\Console\Commands;
+
+use Quantum\Console\Commands\ResourceCacheClearCommand;
+use Symfony\Component\Console\Tester\CommandTester;
+use Quantum\Storage\FileSystem;
+use Quantum\Tests\Unit\AppTestCase;
+
+class ResourceCacheClearCommandTest extends AppTestCase
+{
+    private ResourceCacheClearCommand $command;
+
+    private CommandTester $tester;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->command = new ResourceCacheClearCommand();
+        $this->tester = new CommandTester($this->command);
+    }
+
+    public function testCommandMetadata(): void
+    {
+        $this->assertSame('cache:clear', $this->command->getName());
+        $this->assertSame('Clears resource cache', $this->command->getDescription());
+        $this->assertSame('The command will clear the resource cache', $this->command->getHelp());
+    }
+
+    public function testCommandOptionsAreRegistered(): void
+    {
+        $definition = $this->command->getDefinition();
+
+        $this->assertTrue($definition->hasOption('all'));
+        $this->assertTrue($definition->hasOption('type'));
+        $this->assertTrue($definition->hasOption('module'));
+    }
+
+    public function testConstructorInitializesFileSystem(): void
+    {
+        $fs = $this->getPrivateProperty($this->command, 'fs');
+        $this->assertInstanceOf(FileSystem::class, $fs);
+    }
+
+    public function testExecShowsErrorWhenNoOptionsProvided(): void
+    {
+        config()->set('view_cache', ['cache_dir' => 'cache']);
+
+        $cacheDir = base_dir() . DS . 'cache';
+        if (!is_dir($cacheDir)) {
+            mkdir($cacheDir, 0777, true);
+        }
+
+        $this->tester->execute([]);
+
+        $output = $this->tester->getDisplay();
+        $this->assertStringContainsString('Please specify at least one of the following options', $output);
+
+        @rmdir($cacheDir);
+    }
+}
diff --git a/tests/Unit/Console/Commands/RouteListCommandTest.php b/tests/Unit/Console/Commands/RouteListCommandTest.php
new file mode 100644
index 00000000..58102ea4
--- /dev/null
+++ b/tests/Unit/Console/Commands/RouteListCommandTest.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace Quantum\Tests\Unit\Console\Commands;
+
+use Quantum\Console\Commands\RouteListCommand;
+use Quantum\Tests\Unit\AppTestCase;
+
+class RouteListCommandTest extends AppTestCase
+{
+    private RouteListCommand $command;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->command = new RouteListCommand();
+    }
+
+    public function testCommandMetadata(): void
+    {
+        $this->assertSame('route:list', $this->command->getName());
+        $this->assertSame('Display all registered routes', $this->command->getDescription());
+    }
+
+    public function testCommandOptionsAreRegistered(): void
+    {
+        $definition = $this->command->getDefinition();
+
+        $this->assertTrue($definition->hasOption('module'));
+        $this->assertFalse($definition->getOption('module')->isValueRequired());
+    }
+}
diff --git a/tests/Unit/Console/Commands/ServeCommandTest.php b/tests/Unit/Console/Commands/ServeCommandTest.php
new file mode 100644
index 00000000..7b7079a5
--- /dev/null
+++ b/tests/Unit/Console/Commands/ServeCommandTest.php
@@ -0,0 +1,49 @@
+<?php
+
+namespace Quantum\Tests\Unit\Console\Commands;
+
+use Quantum\Console\Commands\ServeCommand;
+use Quantum\Tests\Unit\AppTestCase;
+
+class ServeCommandTest extends AppTestCase
+{
+    private ServeCommand $command;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->command = new ServeCommand();
+    }
+
+    public function testCommandMetadata(): void
+    {
+        $this->assertSame('serve', $this->command->getName());
+        $this->assertSame('Serves the application on the PHP development server', $this->command->getDescription());
+    }
+
+    public function testCommandOptionsAreRegistered(): void
+    {
+        $definition = $this->command->getDefinition();
+
+        $this->assertTrue($definition->hasOption('host'));
+        $this->assertTrue($definition->hasOption('port'));
+        $this->assertTrue($definition->hasOption('open'));
+    }
+
+    public function testBrowserCommandReturnsArrayForKnownPlatform(): void
+    {
+        $method = new \ReflectionMethod($this->command, 'browserCommand');
+        $method->setAccessible(true);
+
+        $result = $method->invoke($this->command, 'http://localhost:8000');
+
+        if (in_array(PHP_OS_FAMILY, ['Windows', 'Linux', 'Darwin'], true)) {
+            $this->assertIsArray($result);
+            $this->assertCount(2, $result);
+            $this->assertSame('http://localhost:8000', $result[1]);
+        } else {
+            $this->assertNull($result);
+        }
+    }
+}
diff --git a/tests/Unit/Console/Commands/VersionCommandTest.php b/tests/Unit/Console/Commands/VersionCommandTest.php
new file mode 100644
index 00000000..e533d463
--- /dev/null
+++ b/tests/Unit/Console/Commands/VersionCommandTest.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace Quantum\Tests\Unit\Console\Commands;
+
+use Quantum\Console\Commands\VersionCommand;
+use Quantum\Tests\Unit\AppTestCase;
+
+class VersionCommandTest extends AppTestCase
+{
+    private VersionCommand $command;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->command = new VersionCommand();
+    }
+
+    public function testCommandMetadata(): void
+    {
+        $this->assertSame('core:version', $this->command->getName());
+        $this->assertSame('Core version', $this->command->getDescription());
+        $this->assertSame('Printing the current version of the framework into the terminal', $this->command->getHelp());
+    }
+}
diff --git a/tests/Unit/Console/QtCommandTest.php b/tests/Unit/Console/QtCommandTest.php
index c1c918dc..ebe89336 100644
--- a/tests/Unit/Console/QtCommandTest.php
+++ b/tests/Unit/Console/QtCommandTest.php
@@ -7,6 +7,7 @@
 use Symfony\Component\Console\Tester\CommandTester;
 use Symfony\Component\Console\Helper\HelperSet;
 use Quantum\Tests\Unit\AppTestCase;
+use RuntimeException;
 
 class QtCommandTest extends AppTestCase
 {
@@ -97,4 +98,24 @@ public function testConfirmReturnsTrue(): void
 
         $this->assertTrue($this->command->confirm('Confirm action'));
     }
+
+    public function testResolveInputThrowsWhenNotSet(): void
+    {
+        $command = new TestCommand();
+
+        $this->expectException(RuntimeException::class);
+        $this->expectExceptionMessage('Input is not set.');
+
+        $command->getArgument('uuid');
+    }
+
+    public function testResolveOutputThrowsWhenNotSet(): void
+    {
+        $command = new TestCommand();
+
+        $this->expectException(RuntimeException::class);
+        $this->expectExceptionMessage('Output is not set.');
+
+        $command->output('test');
+    }
 }
diff --git a/tests/Unit/Mailer/MailerTest.php b/tests/Unit/Mailer/MailerTest.php
index 98fa204f..97260347 100644
--- a/tests/Unit/Mailer/MailerTest.php
+++ b/tests/Unit/Mailer/MailerTest.php
@@ -2,12 +2,18 @@
 
 namespace Quantum\Tests\Unit\Mailer;
 
+use Quantum\Mailer\Adapters\SendinblueAdapter;
+use Quantum\Mailer\Adapters\MandrillAdapter;
+use Quantum\Mailer\Adapters\SendgridAdapter;
+use Quantum\Mailer\Adapters\MailgunAdapter;
+use Quantum\Mailer\Adapters\ResendAdapter;
 use Quantum\Mailer\Exceptions\MailerException;
 use Quantum\Mailer\Contracts\MailerInterface;
 use Quantum\Mailer\Adapters\SmtpAdapter;
 use Quantum\Tests\Unit\AppTestCase;
 use Quantum\Mailer\Mailer;
 use Quantum\Loader\Setup;
+use ReflectionMethod;
 
 class MailerTest extends AppTestCase
 {
@@ -48,4 +54,37 @@ public function testMailerCallingInvalidMethod(): void
 
         $mailer->callingInvalidMethod();
     }
+
+    /**
+     * @dataProvider httpAdapterProvider
+     */
+    public function testHttpAdapterGetTransportErrorsReturnsArray(string $adapterClass, array $params): void
+    {
+        $adapter = new $adapterClass($params);
+
+        $httpClient = $this->getPrivateProperty($adapter, 'httpClient');
+        $httpClient->createRequest('http://localhost');
+
+        $method = new ReflectionMethod($adapter, 'getTransportErrors');
+        $method->setAccessible(true);
+
+        $errors = $method->invoke($adapter);
+
+        $this->assertIsArray($errors);
+        $this->assertEmpty($errors);
+    }
+
+    /**
+     * @return array<string, array{0: class-string, 1: array<string, mixed>}>
+     */
+    public function httpAdapterProvider(): array
+    {
+        return [
+            'mailgun' => [MailgunAdapter::class, ['api_key' => 'test', 'domain' => 'test.com']],
+            'mandrill' => [MandrillAdapter::class, ['api_key' => 'test']],
+            'resend' => [ResendAdapter::class, ['api_key' => 'test']],
+            'sendgrid' => [SendgridAdapter::class, ['api_key' => 'test']],
+            'sendinblue' => [SendinblueAdapter::class, ['api_key' => 'test']],
+        ];
+    }
 }