diff --git a/shop/lib/utils.ts b/shop/lib/utils.ts
index c3e0acb..b2566c1 100644
--- a/shop/lib/utils.ts
+++ b/shop/lib/utils.ts
@@ -14,16 +14,31 @@ export const hasEnvVars =
 
 export function resolveSupabaseUrl(url: string | undefined): string | undefined {
   if (!url) return url;
+  
+  // Bestimme die externe Basis-URL aus Umgebungsvariablen (falls vorhanden und extern)
+  let extBase = process.env.NEXT_PUBLIC_SUPABASE_URL_EXTERNAL || process.env.NEXT_PUBLIC_SUPABASE_URL || '';
+  if (extBase.includes('kong') || extBase.includes('supabase-kong')) {
+    extBase = ''; // ignorieren, da intern
+  }
+
   if (typeof window !== 'undefined') {
     try {
       const parsed = new URL(url);
       if (parsed.hostname === 'supabase-kong' || parsed.hostname === 'kong') {
-        parsed.hostname = window.location.hostname;
-        parsed.protocol = window.location.protocol;
-        if (window.location.hostname === 'localhost' && parsed.port === '8000') {
-          parsed.port = '8000';
+        if (extBase) {
+          const extUrl = new URL(extBase);
+          parsed.hostname = extUrl.hostname;
+          parsed.port = extUrl.port;
+          parsed.protocol = extUrl.protocol;
         } else {
-          parsed.port = ''; // Port entfernen für Produktion hinter Reverse Proxy
+          // Fallback auf die aktuelle Browser-Domain
+          parsed.hostname = window.location.hostname;
+          parsed.protocol = window.location.protocol;
+          if (window.location.hostname === 'localhost' && parsed.port === '8000') {
+            parsed.port = '8000';
+          } else {
+            parsed.port = ''; // Port entfernen für Produktion hinter Reverse Proxy
+          }
         }
         return parsed.toString().replace(/\/$/, '');
       }
@@ -34,11 +49,21 @@ export function resolveSupabaseUrl(url: string | undefined): string | undefined
         return parsed.toString().replace(/\/$/, '');
       }
     } catch {
-      let resolved = url
-        .replace('//supabase-kong:8000', `//${window.location.hostname}`)
-        .replace('//kong:8000', `//${window.location.hostname}`)
-        .replace('//supabase-kong', `//${window.location.hostname}`)
-        .replace('//kong', `//${window.location.hostname}`);
+      let resolved = url;
+      if (extBase) {
+        const extUrl = new URL(extBase);
+        resolved = resolved
+          .replace('//supabase-kong:8000', `//${extUrl.host}`)
+          .replace('//kong:8000', `//${extUrl.host}`)
+          .replace('//supabase-kong', `//${extUrl.host}`)
+          .replace('//kong', `//${extUrl.host}`);
+      } else {
+        resolved = resolved
+          .replace('//supabase-kong:8000', `//${window.location.hostname}`)
+          .replace('//kong:8000', `//${window.location.hostname}`)
+          .replace('//supabase-kong', `//${window.location.hostname}`)
+          .replace('//kong', `//${window.location.hostname}`);
+      }
       if (window.location.protocol === 'https:') {
         resolved = resolved.replace('http://', 'https://');
       }
@@ -49,20 +74,15 @@ export function resolveSupabaseUrl(url: string | undefined): string | undefined
     try {
       const parsed = new URL(url);
       if (parsed.hostname === 'supabase-kong' || parsed.hostname === 'kong') {
-        if (process.env.NEXT_PUBLIC_SUPABASE_URL_EXTERNAL) {
-          const extUrl = new URL(process.env.NEXT_PUBLIC_SUPABASE_URL_EXTERNAL);
-          parsed.hostname = extUrl.hostname;
-          parsed.port = extUrl.port;
-          parsed.protocol = extUrl.protocol;
-        } else {
-          parsed.hostname = 'localhost';
-          parsed.port = '8000';
-          parsed.protocol = 'http:';
-        }
+        const ext = extBase || 'http://localhost:8000';
+        const extUrl = new URL(ext);
+        parsed.hostname = extUrl.hostname;
+        parsed.port = extUrl.port;
+        parsed.protocol = extUrl.protocol;
         return parsed.toString().replace(/\/$/, '');
       }
     } catch {
-      const target = process.env.NEXT_PUBLIC_SUPABASE_URL_EXTERNAL || 'http://localhost:8000';
+      const target = extBase || 'http://localhost:8000';
       const targetUrl = new URL(target);
       return url
         .replace('//supabase-kong:8000', `//${targetUrl.host}`)