diff --git a/shop/lib/utils.ts b/shop/lib/utils.ts
index 6c02f2e..c3e0acb 100644
--- a/shop/lib/utils.ts
+++ b/shop/lib/utils.ts
@@ -20,7 +20,11 @@ export function resolveSupabaseUrl(url: string | undefined): string | undefined
       if (parsed.hostname === 'supabase-kong' || parsed.hostname === 'kong') {
         parsed.hostname = window.location.hostname;
         parsed.protocol = window.location.protocol;
-        parsed.port = ''; // Port entfernen, da der öffentliche Zugriff über Port 80/443 läuft
+        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(/\/$/, '');
       }
       
@@ -41,22 +45,30 @@ export function resolveSupabaseUrl(url: string | undefined): string | undefined
       return resolved;
     }
   } else {
-    // Server-Side fallback to localhost:8000 (for local development)
-    if (process.env.IS_DOCKER !== 'true') {
-      try {
-        const parsed = new URL(url);
-        if (parsed.hostname === 'supabase-kong' || parsed.hostname === 'kong') {
+    // Server-Side: Umschreiben auf externe URL oder localhost:8000
+    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';
-          return parsed.toString().replace(/\/$/, '');
+          parsed.protocol = 'http:';
         }
-      } catch {
-        return url
-          .replace('//supabase-kong:8000', '//localhost:8000')
-          .replace('//kong:8000', '//localhost:8000')
-          .replace('//supabase-kong', '//localhost:8000')
-          .replace('//kong', '//localhost:8000');
+        return parsed.toString().replace(/\/$/, '');
       }
+    } catch {
+      const target = process.env.NEXT_PUBLIC_SUPABASE_URL_EXTERNAL || 'http://localhost:8000';
+      const targetUrl = new URL(target);
+      return url
+        .replace('//supabase-kong:8000', `//${targetUrl.host}`)
+        .replace('//kong:8000', `//${targetUrl.host}`)
+        .replace('//supabase-kong', `//${targetUrl.host}`)
+        .replace('//kong', `//${targetUrl.host}`);
     }
   }
   return url;