formating and env documentation

.env.example

@@ -1,5 +1,12 @@
-HOSTNAME=localhost
+# Network configuration
+HOSTNAME=localhost  # hostname for service discovery across docker network
 
-# PORTS
+# Application configuration
-KAFKA_PORT=9092
+STORE_MODE=hotel  # platform mode: 'hotel' or 'airline' - determines product catalog and UI theme
-REDIS_PORT=6377
+NEXT_PUBLIC_API_BASE=http://localhost:3000  # base URL for API endpoints, must be valid URL format
+NEXT_PUBLIC_APP_ENV=dev  # application environment: 'dev' or 'prod' - controls logging, error handling
+
+# Service ports - used by docker-compose and service communication
+KAFKA_PORT=9092  # kafka broker port for event streaming
+REDIS_PORT=6377  # redis port for worker queue and caching
+REDPANDA_CONSOLE_PORT=8084  # redpanda console UI port for kafka monitoring

web/package-lock.json

@@ -11,7 +11,8 @@
         "kafkajs": "^2.2.4",
         "next": "16.0.0",
         "react": "19.2.0",
-        "react-dom": "19.2.0"
+        "react-dom": "19.2.0",
+        "zod": "^4.1.12"
       },
       "devDependencies": {
         "@tailwindcss/postcss": "^4",
@@ -1616,6 +1617,15 @@
       "integrity": "sha512-iwDZqg0QAGrg9Rav5H4n0M64c3mkR59cJ6wQp+7C4nI0gsmExaedaYLNO44eT4AtBBwjbTiGPMlt2Md0T9H9JQ==",
       "dev": true,
       "license": "MIT"
+    },
+    "node_modules/zod": {
+      "version": "4.1.12",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-4.1.12.tgz",
+      "integrity": "sha512-JInaHOamG8pt5+Ey8kGmdcAcg3OL9reK8ltczgHTAwNhMys/6ThXHityHxVV2p3fkw/c+MAvBHFVYHFZDmjMCQ==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/colinhacks"
+      }
     }
   }
 }

web/package.json

@@ -11,7 +11,8 @@
     "kafkajs": "^2.2.4",
     "next": "16.0.0",
     "react": "19.2.0",
-    "react-dom": "19.2.0"
+    "react-dom": "19.2.0",
+    "zod": "^4.1.12"
   },
   "devDependencies": {
     "@tailwindcss/postcss": "^4",

web/src/lib/config.ts

@@ -0,0 +1,30 @@
+import { z } from 'zod';
+
+type Env = z.infer<typeof envSchema>;
+const envSchema = z.object({
+    STORE_MODE: z.enum(['hotel', 'airline'], {
+        errorMap: () => ({ message: 'STORE_MODE must be either "hotel" or "airline"' })
+    }),
+    NEXT_PUBLIC_API_BASE: z.string().url({
+        message: 'NEXT_PUBLIC_API_BASE must be a valid URL (e.g., http://localhost:3000)'
+    }),
+    NEXT_PUBLIC_APP_ENV: z.enum(['dev', 'prod'], {
+        errorMap: () => ({ message: 'NEXT_PUBLIC_APP_ENV must be either "dev" or "prod"' })
+    }),
+});
+
+// parse and validate env at module load, fail fast with descriptive errors
+const parseEnv = (): Env => {
+    const result = envSchema.safeParse({
+        STORE_MODE: process.env.STORE_MODE,
+        NEXT_PUBLIC_API_BASE: process.env.NEXT_PUBLIC_API_BASE,
+        NEXT_PUBLIC_APP_ENV: process.env.NEXT_PUBLIC_APP_ENV,
+    });
+    if (!result.success) {
+        const errors = result.error.errors.map((err) => `${err.path.join('.')}: ${err.message}`).join('\n');
+        throw new Error(`Environment validation failed:\n${errors}`);
+    }
+    return result.data;
+};
+
+export const config: Env = parseEnv();