diff --git a/modules.local/ppcp-wc-gateway/extensions.php b/modules.local/ppcp-wc-gateway/extensions.php
index cf4b7cc97..cd16cc0e2 100644
--- a/modules.local/ppcp-wc-gateway/extensions.php
+++ b/modules.local/ppcp-wc-gateway/extensions.php
@@ -35,6 +35,10 @@ return [
         $settings = $container->get('wcgateway.settings');
         return $settings->has('client_secret') ? (string) $settings->get('client_secret') : '';
     },
+    'api.prefix' => static function (ContainerInterface $container): string {
+        $settings = $container->get('wcgateway.settings');
+        return $settings->has('prefix') ? (string) $settings->get('prefix') : 'WC-';
+    },
     'api.endpoint.order' => static function (ContainerInterface $container): OrderEndpoint {
         $orderFactory = $container->get('api.factory.order');
         $patchCollectionFactory = $container->get('api.factory.patch-collection-factory');
diff --git a/modules.local/ppcp-wc-gateway/services.php b/modules.local/ppcp-wc-gateway/services.php
index 9143cd4a2..15e41b05f 100644
--- a/modules.local/ppcp-wc-gateway/services.php
+++ b/modules.local/ppcp-wc-gateway/services.php
@@ -529,6 +529,19 @@ return [
                 ],
                 'requirements' => [],
             ],
+            'prefix' => [
+                'title' => __('Installation prefix', 'woocommerce-paypal-commerce-gateway'),
+                'type' => 'text',
+                'desc_tip' => true,
+                'description' => __('If you use your PayPal account with more than one installation, please use a distinct prefix to seperate those installations. Please do not use numbers in your prefix.', 'woocommerce-paypal-commerce-gateway'),
+                'default' => 'WC-',
+                'screens' => [
+                    State::STATE_START,
+                    State::STATE_PROGRESSIVE,
+                    State::STATE_ONBOARDED,
+                ],
+                'requirements' => [],
+            ],
         ];
     },
 ];
diff --git a/modules.local/ppcp-wc-gateway/src/Settings/SettingsListener.php b/modules.local/ppcp-wc-gateway/src/Settings/SettingsListener.php
index d8a92d9bb..16cc75c39 100644
--- a/modules.local/ppcp-wc-gateway/src/Settings/SettingsListener.php
+++ b/modules.local/ppcp-wc-gateway/src/Settings/SettingsListener.php
@@ -86,6 +86,12 @@ class SettingsListener
                 case 'text':
                     $settings[$key] = isset($rawData[$key]) ? sanitize_text_field($rawData[$key]) : '';
                     break;
+                case 'password':
+                    if (empty($rawData[$key])) {
+                        break;
+                    }
+                    $settings[$key] = sanitize_text_field($rawData[$key]);
+                    break;
                 case 'ppcp-multiselect':
                     $values = isset($rawData[$key]) ? (array) $rawData[$key] : [];
                     $valuesToSave = [];
diff --git a/modules.local/ppcp-webhooks/services.php b/modules.local/ppcp-webhooks/services.php
index 59241ac2e..b9860fda3 100644
--- a/modules.local/ppcp-webhooks/services.php
+++ b/modules.local/ppcp-webhooks/services.php
@@ -39,11 +39,12 @@ return [
     },
     'webhook.endpoint.handler' => function(ContainerInterface $container) : array {
         $logger = $container->get('woocommerce.logger.woocommerce');
+        $prefix = $container->get('api.prefix');
         return [
-            new CheckoutOrderCompleted($logger),
-            new PaymentCaptureRefunded($logger),
-            new PaymentCaptureReversed($logger),
-            new PaymentCaptureCompleted($logger),
+            new CheckoutOrderCompleted($logger, $prefix),
+            new PaymentCaptureRefunded($logger, $prefix),
+            new PaymentCaptureReversed($logger, $prefix),
+            new PaymentCaptureCompleted($logger, $prefix),
         ];
     }
 ];
diff --git a/modules.local/ppcp-webhooks/src/Handler/CheckoutOrderCompleted.php b/modules.local/ppcp-webhooks/src/Handler/CheckoutOrderCompleted.php
index 30abdbb51..85693a48d 100644
--- a/modules.local/ppcp-webhooks/src/Handler/CheckoutOrderCompleted.php
+++ b/modules.local/ppcp-webhooks/src/Handler/CheckoutOrderCompleted.php
@@ -9,10 +9,12 @@ use Psr\Log\LoggerInterface;
 class CheckoutOrderCompleted implements RequestHandler
 {
 
+    use PrefixTrait;
     private $logger;
-    public function __construct(LoggerInterface $logger)
+    public function __construct(LoggerInterface $logger, string $prefix)
     {
         $this->logger = $logger;
+        $this->prefix = $prefix;
     }
 
     public function eventTypes(): array
@@ -32,7 +34,7 @@ class CheckoutOrderCompleted implements RequestHandler
     public function handleRequest(\WP_REST_Request $request): \WP_REST_Response
     {
         $response = ['success' => false];
-        $orderIds = array_filter(
+        $customIds = array_filter(
             array_map(
                 static function (array $purchaseUnit): string {
                     return isset($purchaseUnit['custom_id']) ? (string) $purchaseUnit['custom_id'] : '';
@@ -45,7 +47,7 @@ class CheckoutOrderCompleted implements RequestHandler
             }
         );
 
-        if (empty($orderIds)) {
+        if (empty($customIds)) {
             $message = sprintf(
                 // translators: %s is the PayPal webhook Id.
                 __('No order for webhook event %s was found.', 'woocommerce-paypal-commerce-gateway'),
@@ -62,6 +64,13 @@ class CheckoutOrderCompleted implements RequestHandler
             return rest_ensure_response($response);
         }
 
+        $orderIds = array_map(
+            [
+                $this,
+                'sanitizeCustomId',
+            ],
+            $customIds
+        );
         $args = [
             'post__in' => $orderIds,
             'limit' => -1,
diff --git a/modules.local/ppcp-webhooks/src/Handler/PaymentCaptureCompleted.php b/modules.local/ppcp-webhooks/src/Handler/PaymentCaptureCompleted.php
index ca9859c25..07cb87a31 100644
--- a/modules.local/ppcp-webhooks/src/Handler/PaymentCaptureCompleted.php
+++ b/modules.local/ppcp-webhooks/src/Handler/PaymentCaptureCompleted.php
@@ -10,11 +10,12 @@ use Psr\Log\LoggerInterface;
 class PaymentCaptureCompleted implements RequestHandler
 {
 
+    use PrefixTrait;
     private $logger;
-
-    public function __construct(LoggerInterface $logger)
+    public function __construct(LoggerInterface $logger, string $prefix)
     {
         $this->logger = $logger;
+        $this->prefix = $prefix;
     }
 
     public function eventTypes(): array
@@ -31,7 +32,23 @@ class PaymentCaptureCompleted implements RequestHandler
     public function handleRequest(\WP_REST_Request $request): \WP_REST_Response
     {
         $response = ['success' => false];
-        $orderId = (int) $request['resource']['custom_id'];
+        $orderId = isset($request['resource']['custom_id']) ? $this->sanitizeCustomId($request['resource']['custom_id']) : 0;
+        if (! $orderId) {
+            $message = sprintf(
+                // translators: %s is the PayPal webhook Id.
+                __('No order for webhook event %s was found.', 'woocommerce-paypal-commerce-gateway'),
+                isset($request['id']) ? $request['id'] : ''
+            );
+            $this->logger->log(
+                'warning',
+                $message,
+                [
+                    'request' => $request,
+                ]
+            );
+            $response['message'] = $message;
+            return rest_ensure_response($response);
+        }
         $wcOrder = wc_get_order($orderId);
 
         if (! is_a($wcOrder, \WC_Order::class)) {
diff --git a/modules.local/ppcp-webhooks/src/Handler/PaymentCaptureRefunded.php b/modules.local/ppcp-webhooks/src/Handler/PaymentCaptureRefunded.php
index 0bbdfeeaf..31028cf50 100644
--- a/modules.local/ppcp-webhooks/src/Handler/PaymentCaptureRefunded.php
+++ b/modules.local/ppcp-webhooks/src/Handler/PaymentCaptureRefunded.php
@@ -9,10 +9,12 @@ use Psr\Log\LoggerInterface;
 class PaymentCaptureRefunded implements RequestHandler
 {
 
+    use PrefixTrait;
     private $logger;
-    public function __construct(LoggerInterface $logger)
+    public function __construct(LoggerInterface $logger, string $prefix)
     {
         $this->logger = $logger;
+        $this->prefix = $prefix;
     }
 
     public function eventTypes(): array
@@ -29,7 +31,7 @@ class PaymentCaptureRefunded implements RequestHandler
     public function handleRequest(\WP_REST_Request $request): \WP_REST_Response
     {
         $response = ['success' => false];
-        $orderId = isset($request['resource']['custom_id']) ? (int) $request['resource']['custom_id'] : 0;
+        $orderId = isset($request['resource']['custom_id']) ? $this->sanitizeCustomId($request['resource']['custom_id']) : 0;
         if (! $orderId) {
             $message = sprintf(
             // translators: %s is the PayPal webhook Id.
diff --git a/modules.local/ppcp-webhooks/src/Handler/PaymentCaptureReversed.php b/modules.local/ppcp-webhooks/src/Handler/PaymentCaptureReversed.php
index 70c056339..ea5baffc8 100644
--- a/modules.local/ppcp-webhooks/src/Handler/PaymentCaptureReversed.php
+++ b/modules.local/ppcp-webhooks/src/Handler/PaymentCaptureReversed.php
@@ -9,10 +9,12 @@ use Psr\Log\LoggerInterface;
 class PaymentCaptureReversed implements RequestHandler
 {
 
+    use PrefixTrait;
     private $logger;
-    public function __construct(LoggerInterface $logger)
+    public function __construct(LoggerInterface $logger, string $prefix)
     {
         $this->logger = $logger;
+        $this->prefix = $prefix;
     }
 
     public function eventTypes(): array
@@ -33,7 +35,7 @@ class PaymentCaptureReversed implements RequestHandler
     public function handleRequest(\WP_REST_Request $request): \WP_REST_Response
     {
         $response = ['success' => false];
-        $orderId = isset($request['resource']['custom_id']) ? (int) $request['resource']['custom_id'] : 0;
+        $orderId = isset($request['resource']['custom_id']) ? $this->sanitizeCustomId($request['resource']['custom_id']) : 0;
         if (! $orderId) {
             $message = sprintf(
             // translators: %s is the PayPal webhook Id.
diff --git a/modules.local/ppcp-webhooks/src/Handler/PrefixTrait.php b/modules.local/ppcp-webhooks/src/Handler/PrefixTrait.php
new file mode 100644
index 000000000..eb9e09146
--- /dev/null
+++ b/modules.local/ppcp-webhooks/src/Handler/PrefixTrait.php
@@ -0,0 +1,16 @@
+<?php
+declare(strict_types=1);
+
+namespace Inpsyde\PayPalCommerce\Webhooks\Handler;
+
+
+trait PrefixTrait
+{
+
+    private $prefix = '';
+
+    private function sanitizeCustomId(string $customId) : int {
+        $orderId = str_replace($this->prefix, '', $customId);
+        return (int) $orderId;
+    }
+}
\ No newline at end of file