diff --git a/php/domain-validator.php b/php/domain-validator.php
index 57506b8a..4f622653 100644
--- a/php/domain-validator.php
+++ b/php/domain-validator.php
@@ -1,6 +1,10 @@
 <?php
+declare(strict_types=1);
 
-$domain = $_GET['domain'] ?? '';
+$domain = '';
+if (isset($_GET['domain']) && is_string($_GET['domain'])) {
+    $domain = $_GET['domain'];
+}
 
 if (!str_contains($domain, '.')) { 
     http_response_code(400); 
diff --git a/php/src/Auth/AuthManager.php b/php/src/Auth/AuthManager.php
index f6ab0d10..c2c0c7ac 100644
--- a/php/src/Auth/AuthManager.php
+++ b/php/src/Auth/AuthManager.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Auth;
 
diff --git a/php/src/Auth/PasswordGenerator.php b/php/src/Auth/PasswordGenerator.php
index 6e9ee9a1..a0c4785e 100644
--- a/php/src/Auth/PasswordGenerator.php
+++ b/php/src/Auth/PasswordGenerator.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Auth;
 
diff --git a/php/src/Container/AioVariables.php b/php/src/Container/AioVariables.php
index 10a150f4..9f19bbe7 100644
--- a/php/src/Container/AioVariables.php
+++ b/php/src/Container/AioVariables.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Container;
 
diff --git a/php/src/Container/Container.php b/php/src/Container/Container.php
index 6e5d2b54..67ff72ad 100644
--- a/php/src/Container/Container.php
+++ b/php/src/Container/Container.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Container;
 
diff --git a/php/src/Container/ContainerEnvironmentVariables.php b/php/src/Container/ContainerEnvironmentVariables.php
index 301fcdcf..0b00b7c1 100644
--- a/php/src/Container/ContainerEnvironmentVariables.php
+++ b/php/src/Container/ContainerEnvironmentVariables.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Container;
 
diff --git a/php/src/Container/ContainerPort.php b/php/src/Container/ContainerPort.php
index ff8a6250..a44e3455 100644
--- a/php/src/Container/ContainerPort.php
+++ b/php/src/Container/ContainerPort.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Container;
 
diff --git a/php/src/Container/ContainerPorts.php b/php/src/Container/ContainerPorts.php
index 1e88eebc..62dcf235 100644
--- a/php/src/Container/ContainerPorts.php
+++ b/php/src/Container/ContainerPorts.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Container;
 
diff --git a/php/src/Container/ContainerState.php b/php/src/Container/ContainerState.php
index f6481027..92f00f22 100644
--- a/php/src/Container/ContainerState.php
+++ b/php/src/Container/ContainerState.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Container;
 
diff --git a/php/src/Container/ContainerVolume.php b/php/src/Container/ContainerVolume.php
index e28145a9..a29d82e3 100644
--- a/php/src/Container/ContainerVolume.php
+++ b/php/src/Container/ContainerVolume.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Container;
 
diff --git a/php/src/Container/ContainerVolumes.php b/php/src/Container/ContainerVolumes.php
index 23618df4..c92c0fcc 100644
--- a/php/src/Container/ContainerVolumes.php
+++ b/php/src/Container/ContainerVolumes.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Container;
 
diff --git a/php/src/Container/VersionState.php b/php/src/Container/VersionState.php
index 8eed9301..b54dfbd3 100644
--- a/php/src/Container/VersionState.php
+++ b/php/src/Container/VersionState.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Container;
 
diff --git a/php/src/ContainerDefinitionFetcher.php b/php/src/ContainerDefinitionFetcher.php
index d2519ed7..bacc322b 100644
--- a/php/src/ContainerDefinitionFetcher.php
+++ b/php/src/ContainerDefinitionFetcher.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO;
 
diff --git a/php/src/Controller/ConfigurationController.php b/php/src/Controller/ConfigurationController.php
index c40ee98c..2cc56b65 100644
--- a/php/src/Controller/ConfigurationController.php
+++ b/php/src/Controller/ConfigurationController.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Controller;
 
diff --git a/php/src/Controller/DockerController.php b/php/src/Controller/DockerController.php
index 81b920d0..9d9eab2f 100644
--- a/php/src/Controller/DockerController.php
+++ b/php/src/Controller/DockerController.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Controller;
 
diff --git a/php/src/Controller/LoginController.php b/php/src/Controller/LoginController.php
index 412ff9df..a90bde26 100644
--- a/php/src/Controller/LoginController.php
+++ b/php/src/Controller/LoginController.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Controller;
 
diff --git a/php/src/Data/ConfigurationManager.php b/php/src/Data/ConfigurationManager.php
index 7534acda..264af861 100644
--- a/php/src/Data/ConfigurationManager.php
+++ b/php/src/Data/ConfigurationManager.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Data;
 
diff --git a/php/src/Data/DataConst.php b/php/src/Data/DataConst.php
index 9272e3d4..10d5342b 100644
--- a/php/src/Data/DataConst.php
+++ b/php/src/Data/DataConst.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Data;
 
diff --git a/php/src/Data/Setup.php b/php/src/Data/Setup.php
index e409eef8..d101a762 100644
--- a/php/src/Data/Setup.php
+++ b/php/src/Data/Setup.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Data;
 
diff --git a/php/src/DependencyInjection.php b/php/src/DependencyInjection.php
index 1fedada8..a7035a96 100644
--- a/php/src/DependencyInjection.php
+++ b/php/src/DependencyInjection.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO;
 
diff --git a/php/src/Docker/DockerActionManager.php b/php/src/Docker/DockerActionManager.php
index 86b36619..d6a52d93 100644
--- a/php/src/Docker/DockerActionManager.php
+++ b/php/src/Docker/DockerActionManager.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Docker;
 
diff --git a/php/src/Docker/DockerHubManager.php b/php/src/Docker/DockerHubManager.php
index 256d592e..c11d81eb 100644
--- a/php/src/Docker/DockerHubManager.php
+++ b/php/src/Docker/DockerHubManager.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Docker;
 
diff --git a/php/src/Docker/GitHubContainerRegistryManager.php b/php/src/Docker/GitHubContainerRegistryManager.php
index eeecfb28..cc92f944 100644
--- a/php/src/Docker/GitHubContainerRegistryManager.php
+++ b/php/src/Docker/GitHubContainerRegistryManager.php
@@ -1,5 +1,5 @@
 <?php
-
+declare(strict_types=1);
 
 namespace AIO\Docker;
 
diff --git a/php/src/Middleware/AuthMiddleware.php b/php/src/Middleware/AuthMiddleware.php
index 724f1776..8cea8db1 100644
--- a/php/src/Middleware/AuthMiddleware.php
+++ b/php/src/Middleware/AuthMiddleware.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Middleware;
 
diff --git a/php/src/Twig/ClassExtension.php b/php/src/Twig/ClassExtension.php
index 7f478994..b80d95c0 100644
--- a/php/src/Twig/ClassExtension.php
+++ b/php/src/Twig/ClassExtension.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Twig;
 
diff --git a/php/src/Twig/CsrfExtension.php b/php/src/Twig/CsrfExtension.php
index 51334864..ba478308 100644
--- a/php/src/Twig/CsrfExtension.php
+++ b/php/src/Twig/CsrfExtension.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 
 namespace AIO\Twig;