diff --git a/src/Handler/Certificate/ApplePayDirectCertificateHandler.php b/src/Handler/Certificate/ApplePayDirectCertificateHandler.php
index bf871b219..f32b3e863 100644
--- a/src/Handler/Certificate/ApplePayDirectCertificateHandler.php
+++ b/src/Handler/Certificate/ApplePayDirectCertificateHandler.php
@@ -16,6 +16,10 @@
 use Mollie\Handler\Certificate\Exception\ApplePayDirectCertificateCreation;
 use Mollie\Utility\FileUtility;
 
+if (!defined('_PS_VERSION_')) {
+    exit;
+}
+
 class ApplePayDirectCertificateHandler implements CertificateHandlerInterface
 {
     const FILE_NAME = 'ApplePayDirectCertificateHandler';
diff --git a/src/Handler/Certificate/Exception/ApplePayDirectCertificateCreation.php b/src/Handler/Certificate/Exception/ApplePayDirectCertificateCreation.php
index eb1b9d1ce..06fd25f42 100644
--- a/src/Handler/Certificate/Exception/ApplePayDirectCertificateCreation.php
+++ b/src/Handler/Certificate/Exception/ApplePayDirectCertificateCreation.php
@@ -12,6 +12,10 @@
 
 namespace Mollie\Handler\Certificate\Exception;
 
+if (!defined('_PS_VERSION_')) {
+    exit;
+}
+
 class ApplePayDirectCertificateCreation extends CertificationException
 {
 }
diff --git a/src/Handler/Exception/OrderExceptionHandler.php b/src/Handler/Exception/OrderExceptionHandler.php
index cdc39ac10..eb78838fb 100644
--- a/src/Handler/Exception/OrderExceptionHandler.php
+++ b/src/Handler/Exception/OrderExceptionHandler.php
@@ -15,6 +15,10 @@
 use Exception;
 use Mollie\Exception\OrderCreationException;
 
+if (!defined('_PS_VERSION_')) {
+    exit;
+}
+
 class OrderExceptionHandler implements ExceptionHandlerInterface
 {
     /**
diff --git a/src/Handler/RetryHandlerInterface.php b/src/Handler/RetryHandlerInterface.php
index 197988de3..6d5cb036b 100644
--- a/src/Handler/RetryHandlerInterface.php
+++ b/src/Handler/RetryHandlerInterface.php
@@ -12,6 +12,10 @@
 
 namespace Mollie\Handler;
 
+if (!defined('_PS_VERSION_')) {
+    exit;
+}
+
 interface RetryHandlerInterface
 {
     public function retry($function, array $options = [], $moreOptions = []);
diff --git a/src/Handler/Settings/PaymentMethodPositionHandlerInterface.php b/src/Handler/Settings/PaymentMethodPositionHandlerInterface.php
index 5ce149f77..eb85ee8d5 100644
--- a/src/Handler/Settings/PaymentMethodPositionHandlerInterface.php
+++ b/src/Handler/Settings/PaymentMethodPositionHandlerInterface.php
@@ -12,6 +12,10 @@
 
 namespace Mollie\Handler\Settings;
 
+if (!defined('_PS_VERSION_')) {
+    exit;
+}
+
 interface PaymentMethodPositionHandlerInterface
 {
     /**
diff --git a/src/Handler/Shipment/ShipmentSenderHandlerInterface.php b/src/Handler/Shipment/ShipmentSenderHandlerInterface.php
index 27e9412d6..bdf28cd42 100644
--- a/src/Handler/Shipment/ShipmentSenderHandlerInterface.php
+++ b/src/Handler/Shipment/ShipmentSenderHandlerInterface.php
@@ -18,6 +18,10 @@
 use Order;
 use OrderState;
 
+if (!defined('_PS_VERSION_')) {
+    exit;
+}
+
 interface ShipmentSenderHandlerInterface
 {
     /**
diff --git a/src/Install/DatabaseTableUninstaller.php b/src/Install/DatabaseTableUninstaller.php
index 2dde9bee9..30510c4ee 100644
--- a/src/Install/DatabaseTableUninstaller.php
+++ b/src/Install/DatabaseTableUninstaller.php
@@ -14,6 +14,10 @@
 
 use Db;
 
+if (!defined('_PS_VERSION_')) {
+    exit;
+}
+
 final class DatabaseTableUninstaller implements UninstallerInterface
 {
     public function uninstall(): bool
diff --git a/src/Logger/PrestaLogger.php b/src/Logger/PrestaLogger.php
index 92fd95bf7..950dd4cbc 100644
--- a/src/Logger/PrestaLogger.php
+++ b/src/Logger/PrestaLogger.php
@@ -16,6 +16,10 @@
 use Mollie\Config\Config;
 use Mollie\Exception\NotImplementedException;
 
+if (!defined('_PS_VERSION_')) {
+    exit;
+}
+
 class PrestaLogger implements PrestaLoggerInterface
 {
     // TODO refactor whole logger logic and implement leftover methods
diff --git a/src/Provider/CustomLogoProviderInterface.php b/src/Provider/CustomLogoProviderInterface.php
index 63d03848a..e91977710 100644
--- a/src/Provider/CustomLogoProviderInterface.php
+++ b/src/Provider/CustomLogoProviderInterface.php
@@ -14,6 +14,10 @@
 
 use MolPaymentMethod;
 
+if (!defined('_PS_VERSION_')) {
+    exit;
+}
+
 interface CustomLogoProviderInterface
 {
     /**
diff --git a/src/Provider/EnvironmentVersionProviderInterface.php b/src/Provider/EnvironmentVersionProviderInterface.php
index b511cfcdf..8829ce917 100644
--- a/src/Provider/EnvironmentVersionProviderInterface.php
+++ b/src/Provider/EnvironmentVersionProviderInterface.php
@@ -12,6 +12,10 @@
 
 namespace Mollie\Provider;
 
+if (!defined('_PS_VERSION_')) {
+    exit;
+}
+
 interface EnvironmentVersionProviderInterface
 {
     /**
diff --git a/src/Provider/OrderTotal/OrderTotalProviderInterface.php b/src/Provider/OrderTotal/OrderTotalProviderInterface.php
index 00a0a1f5c..8816c845a 100644
--- a/src/Provider/OrderTotal/OrderTotalProviderInterface.php
+++ b/src/Provider/OrderTotal/OrderTotalProviderInterface.php
@@ -36,6 +36,10 @@
 
 namespace Mollie\Provider\OrderTotal;
 
+if (!defined('_PS_VERSION_')) {
+    exit;
+}
+
 interface OrderTotalProviderInterface
 {
     public function getOrderTotal(): float;
diff --git a/src/Provider/Shipment/AutomaticShipmentSenderStatusesProviderInterface.php b/src/Provider/Shipment/AutomaticShipmentSenderStatusesProviderInterface.php
index ec12b4812..cbf1a951b 100644
--- a/src/Provider/Shipment/AutomaticShipmentSenderStatusesProviderInterface.php
+++ b/src/Provider/Shipment/AutomaticShipmentSenderStatusesProviderInterface.php
@@ -12,6 +12,10 @@
 
 namespace Mollie\Provider\Shipment;
 
+if (!defined('_PS_VERSION_')) {
+    exit;
+}
+
 interface AutomaticShipmentSenderStatusesProviderInterface
 {
     /**
diff --git a/src/Provider/UpdateMessageProvider.php b/src/Provider/UpdateMessageProvider.php
index 58a38fc9c..655c3b120 100755
--- a/src/Provider/UpdateMessageProvider.php
+++ b/src/Provider/UpdateMessageProvider.php
@@ -17,6 +17,10 @@
 use SimpleXMLElement;
 use Tools;
 
+if (!defined('_PS_VERSION_')) {
+    exit;
+}
+
 class UpdateMessageProvider implements UpdateMessageProviderInterface
 {
     const FILE_NAME = 'UpdateMessageProvider';
diff --git a/src/Provider/UpdateMessageProviderInterface.php b/src/Provider/UpdateMessageProviderInterface.php
index a723f0226..fda8f68dd 100644
--- a/src/Provider/UpdateMessageProviderInterface.php
+++ b/src/Provider/UpdateMessageProviderInterface.php
@@ -12,6 +12,10 @@
 
 namespace Mollie\Provider;
 
+if (!defined('_PS_VERSION_')) {
+    exit;
+}
+
 interface UpdateMessageProviderInterface
 {
     /**