added express payload validation

backend/src/middleware/rateLimit.ts

@@ -0,0 +1,16 @@
+import rateLimit from 'express-rate-limit';
+
+export const authLimiter = rateLimit({
+  windowMs: 15 * 60 * 1000, // 15 minutes
+  max: 5, // Limit each IP to 5 login requests per windowMs
+  message: { error: 'Zu viele Login-Versuche, bitte versuchen Sie es später erneut' },
+  standardHeaders: true,
+  legacyHeaders: false,
+});
+
+export const apiLimiter = rateLimit({
+  windowMs: 15 * 60 * 1000, // 15 minutes
+  max: 100, // Limit each IP to 100 requests per windowMs
+  standardHeaders: true,
+  legacyHeaders: false,
+});