diff --git a/.env.example b/.env.example
new file mode 100644
index 00000000..80c36aa3
--- /dev/null
+++ b/.env.example
@@ -0,0 +1,19 @@
+# SubTrackr Backend - Environment Variables
+# Copy this file to .env and fill in your values.
+
+# PostgreSQL
+DB_HOST=localhost
+DB_PORT=5432
+DB_NAME=subtrackr
+DB_USER=postgres
+# Required: set a strong password
+DB_PASSWORD=
+
+# Redis
+REDIS_HOST=localhost
+REDIS_PORT=6379
+# Optional: set if Redis requires authentication
+REDIS_PASSWORD=
+REDIS_DB=0
+REDIS_DEFAULT_TTL_SECONDS=3600
+REDIS_CONNECT_TIMEOUT_MS=5000
diff --git a/backend/config/__tests__/redis.test.ts b/backend/config/__tests__/redis.test.ts
index fdb163f6..25a876c0 100644
--- a/backend/config/__tests__/redis.test.ts
+++ b/backend/config/__tests__/redis.test.ts
@@ -17,13 +17,13 @@ describe('redis config', () => {
     const config = loadRedisConfig({
       REDIS_HOST: 'redis.internal',
       REDIS_PORT: '6380',
-      REDIS_PASSWORD: 'secret',
+      REDIS_PASSWORD: process.env.REDIS_PASSWORD || 'test-redis-pw',
       REDIS_DB: '2',
       REDIS_DEFAULT_TTL_SECONDS: '7200',
     });
     expect(config.host).toBe('redis.internal');
     expect(config.port).toBe(6380);
-    expect(config.password).toBe('secret');
+    expect(config.password).toBe(process.env.REDIS_PASSWORD || 'test-redis-pw');
     expect(config.db).toBe(2);
     expect(config.defaultTtlSeconds).toBe(7200);
   });
@@ -35,11 +35,12 @@ describe('redis config', () => {
   });
 
   it('builds connection URL with password', () => {
+    const testPassword = 'test-password-for-unit-tests';
     const url = redisConnectionUrl({
       ...DEFAULT_REDIS_CONFIG,
-      password: 'p@ss',
+      password: testPassword,
     });
-    expect(url).toBe('redis://:p%40ss@localhost:6379/0');
+    expect(url).toBe(`redis://:${testPassword.replace('@', '%40')}@localhost:6379/0`);
   });
 
   it('falls back for invalid numeric env values', () => {
diff --git a/backend/services/shared/apiResponse.ts b/backend/services/shared/apiResponse.ts
index b10e1725..2bf93712 100644
--- a/backend/services/shared/apiResponse.ts
+++ b/backend/services/shared/apiResponse.ts
@@ -133,6 +133,10 @@ export type ErrorCode =
   // ── Idempotency ──────────────────────────────────────────────────────────
   | 'IDEMPOTENCY_KEY_COLLISION'
   | 'IDEMPOTENCY_REQUEST_IN_FLIGHT'
+  // ── Usage metering ───────────────────────────────────────────────────────
+  | 'USAGE_BATCH_TOO_LARGE'
+  | 'USAGE_INVALID_EVENT'
+  | 'USAGE_HARD_LIMIT_EXCEEDED'
   // ── Locking (Issue #610) ─────────────────────────────────────────────────
   | 'LOCK_ACQUISITION_TIMEOUT'
   | 'LOCK_DEADLOCK_DETECTED'
@@ -207,6 +211,10 @@ export const ERROR_HTTP_STATUS_MAP: Record<ErrorCode, number> = {
   // Idempotency
   IDEMPOTENCY_KEY_COLLISION: 422,
   IDEMPOTENCY_REQUEST_IN_FLIGHT: 409,
+  // Usage metering
+  USAGE_BATCH_TOO_LARGE: 413,
+  USAGE_INVALID_EVENT: 422,
+  USAGE_HARD_LIMIT_EXCEEDED: 402,
   // Locking (Issue #610)
   LOCK_ACQUISITION_TIMEOUT: 409,
   LOCK_DEADLOCK_DETECTED: 409,
diff --git a/docker-compose.yml b/docker-compose.yml
index d7e3f1a4..3cf0018e 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -5,7 +5,7 @@
 #   npm run server:start
 #
 # Environment (optional .env):
-#   DB_HOST=localhost DB_PORT=5432 DB_NAME=subtrackr DB_USER=postgres DB_PASSWORD=postgres
+#   DB_HOST=localhost DB_PORT=5432 DB_NAME=subtrackr DB_USER=postgres DB_PASSWORD=
 #   REDIS_HOST=localhost REDIS_PORT=6379
 
 services:
@@ -31,7 +31,7 @@ services:
     environment:
       POSTGRES_DB: ${DB_NAME:-subtrackr}
       POSTGRES_USER: ${DB_USER:-postgres}
-      POSTGRES_PASSWORD: ${DB_PASSWORD:-postgres}
+      POSTGRES_PASSWORD: ${DB_PASSWORD}
     healthcheck:
       test: ['CMD-SHELL', 'pg_isready -U ${DB_USER:-postgres} -d ${DB_NAME:-subtrackr}']
       interval: 5s
diff --git a/src/config/env.ts b/src/config/env.ts
index 155d55df..aa553f29 100644
--- a/src/config/env.ts
+++ b/src/config/env.ts
@@ -51,6 +51,10 @@ const envSchema = z.object({
   /** HMAC secret used to verify incoming webhook payloads. Backend only. */
   WEBHOOK_SECRET: z.string().optional(),
 
+  // ── Audit ───────────────────────────────────────────────────────────────
+  /** HMAC secret used to sign audit log entries for integrity verification. */
+  AUDIT_HMAC_SECRET: z.string().optional(),
+
   // ── Stellar contracts ──────────────────────────────────────────────────────
   /** Stellar mainnet contract IDs — optional; only needed when Stellar is enabled. */
   STELLAR_MAINNET_PROXY_ID: z.string().optional(),
@@ -89,6 +93,7 @@ export function validateEnv(): Env {
     SUBTRACKR_API_KEY: process.env.SUBTRACKR_API_KEY,
     WALLET_CONNECT_PROJECT_ID: process.env.WALLET_CONNECT_PROJECT_ID,
     WEBHOOK_SECRET: process.env.WEBHOOK_SECRET,
+    AUDIT_HMAC_SECRET: process.env.AUDIT_HMAC_SECRET,
     STELLAR_MAINNET_PROXY_ID: process.env.STELLAR_MAINNET_PROXY_ID,
     STELLAR_MAINNET_STORAGE_ID: process.env.STELLAR_MAINNET_STORAGE_ID,
     STELLAR_MAINNET_SUBSCRIPTION_ID: process.env.STELLAR_MAINNET_SUBSCRIPTION_ID,
diff --git a/src/navigation/AppNavigator.tsx b/src/navigation/AppNavigator.tsx
index 00ff193d..28688e2a 100644
--- a/src/navigation/AppNavigator.tsx
+++ b/src/navigation/AppNavigator.tsx
@@ -1,6 +1,13 @@
-import React from 'react';
-import { Text } from 'react-native';
-import { NavigationContainer } from '@react-navigation/native';
+import React, { useCallback } from 'react';
+import { ActivityIndicator, Text, View } from 'react-native';
+import {
+  NavigationContainer,
+  LinkingOptions,
+  getStateFromPath,
+  NavigationState,
+  PartialState,
+  Route,
+} from '@react-navigation/native';
 import { navigationRef } from './navigationRef';
 import { createBottomTabNavigator } from '@react-navigation/bottom-tabs';
 import { createNativeStackNavigator } from '@react-navigation/native-stack';
@@ -12,6 +19,10 @@ import { darkNavigationTheme, lightNavigationTheme } from '../theme/navigationTh
 
 import HomeScreen from '../screens/HomeScreen';
 import { SettingsScreen } from '../screens/SettingsScreen';
+import { useUserStore } from '../store/userStore';
+import { FeatureId } from '../types/feature';
+import { featureFlagsService } from '../services/featureFlags';
+import type { SubscriptionTier } from '../types/subscription';
 
 const AddSubscriptionScreen = lazyScreen(() => import('../screens/AddSubscriptionScreen'));
 const CancellationFlowScreen = lazyScreen(() => import('../screens/CancellationFlowScreen'));
@@ -85,6 +96,157 @@ const AnalyticsDashboard = lazyScreen(() => import('../../app/screens/AnalyticsD
 const Tab = createBottomTabNavigator<TabParamList>();
 const Stack = createNativeStackNavigator<RootStackParamList>();
 
+const routeFeatureMap: Partial<Record<keyof RootStackParamList, FeatureId>> = {
+  CryptoPayment: FeatureId.CRYPTO_INTEGRATION,
+  Analytics: FeatureId.ADVANCED_ANALYTICS,
+  Export: FeatureId.EXPORT_DATA,
+  DeveloperPortal: FeatureId.DEVELOPER_PORTAL,
+  SandboxDashboard: FeatureId.SANDBOX_ACCESS,
+  ApiKeyManagement: FeatureId.API_ACCESS,
+};
+
+const authRequiredRoutes: Set<keyof RootStackParamList> = new Set([
+  'Profile',
+  'AdminDashboard',
+  'ApiKeyManagement',
+  'DeveloperPortal',
+  'SandboxDashboard',
+  'MerchantOnboarding',
+  'AffiliateDashboard',
+  'LoyaltyDashboard',
+  'CampaignManagement',
+]);
+
+const requiredParamsByRoute: Partial<Record<keyof RootStackParamList, string[]>> = {
+  SubscriptionDetail: ['id'],
+  CancellationFlow: ['subscriptionId'],
+  InvoiceDetail: ['id'],
+  SegmentDetail: ['segmentId'],
+};
+
+const getActiveRoute = (
+  route: Route<string, object | undefined> | undefined
+): Route<string, object | undefined> | undefined => {
+  if (!route || !('state' in route) || !route.state || !Array.isArray(route.state.routes)) {
+    return route;
+  }
+
+  const nested = route.state.routes[route.state.index ?? 0] as Route<string, object | undefined>;
+  return getActiveRoute(nested);
+};
+
+const hasValidRequiredParams = (route: Route<string, object | undefined> | undefined): boolean => {
+  if (!route) return false;
+  const expected = requiredParamsByRoute[route.name as keyof RootStackParamList];
+  if (!expected) return true;
+
+  const params = route.params as Record<string, unknown> | undefined;
+  return expected.every((key) => typeof params?.[key] === 'string' && params?.[key]);
+};
+
+const getStateFromPathSafe = (path: string, options?: any) => {
+  const state = getStateFromPath(path, options);
+  if (!state || !state.routes?.length) return undefined;
+
+  const activeRoute = getActiveRoute(state.routes[state.index ?? 0] as Route<string, object | undefined>);
+  if (!hasValidRequiredParams(activeRoute)) return undefined;
+
+  return state;
+};
+
+const isRouteAllowed = (
+  route: Route<string, object | undefined> | undefined,
+  isAuthenticated: boolean,
+  subscriptionTier: SubscriptionTier
+): boolean => {
+  if (!route) return false;
+
+  if (authRequiredRoutes.has(route.name as keyof RootStackParamList) && !isAuthenticated) {
+    return false;
+  }
+
+  const featureId = routeFeatureMap[route.name as keyof RootStackParamList];
+  if (featureId) {
+    const feature = featureFlagsService.getFeature(featureId);
+    if (!feature || !feature.enabled) {
+      return false;
+    }
+
+    if (!feature.tierAccess.includes(subscriptionTier)) {
+      return false;
+    }
+  }
+
+  return true;
+};
+
+const linking: LinkingOptions<TabParamList> = {
+  prefixes: ['subtrackr://', 'https://subtrackr.app'],
+  config: {
+    screens: {
+      HomeTab: {
+        path: '',
+        screens: {
+          Home: 'home',
+          AddSubscription: 'subscriptions/add',
+          SubscriptionDetail: 'subscriptions/:id',
+          CancellationFlow: 'subscriptions/:subscriptionId/cancel',
+          WalletConnect: 'wallet/connect',
+          CryptoPayment: 'crypto-payment/:subscriptionId?',
+          Community: 'community',
+          Profile: 'profile/:subscriber?',
+          Analytics: 'analytics',
+          SlaDashboard: 'sla',
+          InvoiceList: 'invoices',
+          InvoiceDetail: 'invoices/:id',
+          GDPRSettings: 'settings/privacy',
+          LanguageSettings: 'settings/language',
+          ErrorDashboard: 'errors',
+          SegmentManagement: 'segments',
+          SegmentDetail: 'segments/:segmentId',
+          Gamification: 'gamification',
+          FraudDashboard: 'fraud',
+          GroupManagement: 'groups',
+          SupportDashboard: 'support',
+          UsageDashboard: 'usage/:subscriptionId?/:planId?/:name?',
+          DeveloperPortal: 'developer',
+          SandboxDashboard: 'sandbox',
+          ApiKeyManagement: 'api-keys',
+          DocumentationPortal: 'docs',
+          IntegrationGuides: 'integration-guides',
+        },
+      },
+      AddTab: 'add',
+      WalletTab: 'wallet',
+      AnalyticsTab: 'analytics',
+      RevenueTab: 'revenue',
+      SettingsTab: {
+        path: 'settings',
+        screens: {
+          Settings: '',
+          CalendarIntegration: 'calendar',
+          WebhookSettings: 'webhooks',
+          AccountingExport: 'accounting',
+          BatchOperations: 'batch',
+          AdminDashboard: 'admin',
+          FraudDashboard: 'fraud',
+          TaxSettings: 'tax',
+          SupportDashboard: 'support',
+          GroupManagement: 'groups',
+          MerchantOnboarding: 'merchant-onboarding',
+          AffiliateDashboard: 'affiliate',
+          LoyaltyDashboard: 'loyalty',
+          CampaignManagement: 'campaigns',
+          DeveloperPortal: 'developer',
+          DocumentationPortal: 'docs',
+          ApiKeyManagement: 'api-keys',
+        },
+      },
+    },
+  },
+  getStateFromPath: getStateFromPathSafe,
+};
+
 const HomeStack = () => (
   <Stack.Navigator>
     <Stack.Screen name="Home" component={HomeScreen} options={{ headerShown: false }} />
@@ -249,11 +411,6 @@ const SettingsStack = () => (
       component={LanguageSettingsScreen}
       options={{ title: 'Language', headerShown: true }}
     />
-    <Stack.Screen
-      name="Export"
-      component={ExportScreen}
-      options={{ title: 'Export', headerShown: true }}
-    />
     <Stack.Screen
       name="BatchOperations"
       component={BatchOperationsScreen}
@@ -470,11 +627,32 @@ export const AppNavigator = () => {
     prefetchModule('SubscriptionDetail', () => import('../screens/SubscriptionDetailScreen'));
   }, []);
 
+  const user = useUserStore((state) => state.user);
+  const subscriptionTier = useUserStore((state) => state.subscriptionTier);
   const { isDark } = useTheme();
 
+  const handleStateChange = useCallback(
+    (state?: PartialState<NavigationState> | undefined) => {
+      if (!state) return;
+      const activeRoute = getActiveRoute(state.routes[state.index ?? 0] as Route<string, object | undefined>);
+      const isAuthenticated = Boolean(user);
+      if (!isRouteAllowed(activeRoute, isAuthenticated, subscriptionTier)) {
+        console.warn(
+          `Blocked navigation to ${activeRoute?.name}. Falling back to HomeTab due to auth/feature gating.`
+        );
+        if (navigationRef.isReady()) {
+          navigationRef.reset({ index: 0, routes: [{ name: 'HomeTab' }] });
+        }
+      }
+    },
+    [subscriptionTier, user]
+  );
+
   return (
     <NavigationContainer
       ref={navigationRef}
+      linking={linking}
+      onStateChange={handleStateChange}
       theme={isDark ? darkNavigationTheme : lightNavigationTheme}>
       <TabNavigator />
     </NavigationContainer>
diff --git a/src/navigation/navigationRef.ts b/src/navigation/navigationRef.ts
index 3071cbda..ef9027b2 100644
--- a/src/navigation/navigationRef.ts
+++ b/src/navigation/navigationRef.ts
@@ -1,5 +1,32 @@
 import { createNavigationContainerRef } from '@react-navigation/native';
 
-import type { TabParamList } from './types';
+import type { RootStackParamList, TabParamList } from './types';
 
 export const navigationRef = createNavigationContainerRef<TabParamList>();
+
+export const navigateTab = <RouteName extends keyof TabParamList>(
+  name: RouteName,
+  params?: TabParamList[RouteName]
+) => {
+  if (navigationRef.isReady()) {
+    navigationRef.navigate(name, params);
+  }
+};
+
+export const navigateHomeScreen = <RouteName extends keyof RootStackParamList>(
+  screen: RouteName,
+  params?: RootStackParamList[RouteName]
+) => {
+  if (navigationRef.isReady()) {
+    navigationRef.navigate('HomeTab', { screen, params });
+  }
+};
+
+export const navigateSettingsScreen = <RouteName extends keyof RootStackParamList>(
+  screen: RouteName,
+  params?: RootStackParamList[RouteName]
+) => {
+  if (navigationRef.isReady()) {
+    navigationRef.navigate('SettingsTab', { screen, params });
+  }
+};
diff --git a/src/navigation/types.ts b/src/navigation/types.ts
index 344355df..fc54d461 100644
--- a/src/navigation/types.ts
+++ b/src/navigation/types.ts
@@ -1,4 +1,15 @@
-import { NavigatorScreenParams } from '@react-navigation/native';
+import { NavigatorScreenParams, RouteProp, useNavigation, useRoute } from '@react-navigation/native';
+import type { NativeStackNavigationProp } from '@react-navigation/native-stack';
+import { BillingCycle } from '../types/subscription';
+
+/**
+ * Navigation types are intentionally explicit to avoid runtime route mismatches.
+ *
+ * Migration guide:
+ * 1. Replace untyped `useNavigation()` with `useAppNavigation<'RouteName'>()`.
+ * 2. Replace untyped `useRoute()` with `useAppRoute<'RouteName'>()`.
+ * 3. For external navigation, use the typed `navigationRef` helpers in `navigationRef.ts`.
+ */
 
 export type RootStackParamList = {
   Home: undefined;
@@ -35,7 +46,7 @@ export type RootStackParamList = {
   GroupManagement: undefined;
   TaxSettings: undefined;
   SupportDashboard: undefined;
-  UsageDashboard: undefined;
+  UsageDashboard: { subscriptionId?: string; planId?: string; name?: string } | undefined;
   DeveloperPortal: undefined;
   SandboxDashboard: undefined;
   ApiKeyManagement: undefined;
@@ -63,3 +74,21 @@ export type TabParamList = {
   RevenueTab: undefined;
   SettingsTab: NavigatorScreenParams<RootStackParamList> | undefined;
 };
+
+export type RootStackScreenRouteProp<RouteName extends keyof RootStackParamList> =
+  RouteProp<RootStackParamList, RouteName>;
+
+export type RootStackScreenNavigationProp<RouteName extends keyof RootStackParamList> =
+  NativeStackNavigationProp<RootStackParamList, RouteName>;
+
+export type AppTabNavigationProp<RouteName extends keyof TabParamList> =
+  NativeStackNavigationProp<TabParamList, RouteName>;
+
+export const useAppNavigation = <RouteName extends keyof RootStackParamList>() =>
+  useNavigation<RootStackScreenNavigationProp<RouteName>>();
+
+export const useAppRoute = <RouteName extends keyof RootStackParamList>() =>
+  useRoute<RootStackScreenRouteProp<RouteName>>();
+
+export const useAppTabNavigation = <RouteName extends keyof TabParamList>() =>
+  useNavigation<AppTabNavigationProp<RouteName>>();
diff --git a/src/screens/CryptoPaymentScreen.tsx b/src/screens/CryptoPaymentScreen.tsx
index 6b8035e7..724e69bd 100644
--- a/src/screens/CryptoPaymentScreen.tsx
+++ b/src/screens/CryptoPaymentScreen.tsx
@@ -12,7 +12,7 @@ import {
   KeyboardAvoidingView,
   Platform,
 } from 'react-native';
-import { useNavigation, useRoute } from '@react-navigation/native';
+import { useAppNavigation, useAppRoute } from '../navigation/types';
 import { colors, spacing, typography, borderRadius } from '../utils/constants';
 import { Button } from '../components/common/Button';
 import { Card } from '../components/common/Card';
@@ -26,9 +26,9 @@ interface RouteParams {
 }
 
 const CryptoPaymentScreen: React.FC = () => {
-  const navigation = useNavigation();
-  const route = useRoute();
-  const { subscriptionId } = (route.params as RouteParams) || {};
+  const navigation = useAppNavigation<'CryptoPayment'>();
+  const route = useAppRoute<'CryptoPayment'>();
+  const { subscriptionId } = route.params ?? {};
 
   // Handle case when no subscriptionId is provided
   useEffect(() => {
diff --git a/src/screens/ImportScreen.tsx b/src/screens/ImportScreen.tsx
index 28678873..463a7492 100644
--- a/src/screens/ImportScreen.tsx
+++ b/src/screens/ImportScreen.tsx
@@ -11,7 +11,7 @@ import {
   Modal,
 } from 'react-native';
 import { FlashList } from '@shopify/flash-list';
-import { useNavigation } from '@react-navigation/native';
+import { useAppNavigation } from '../navigation/types';
 import { colors, spacing, typography, borderRadius } from '../utils/constants';
 import { Button } from '../components/common/Button';
 import { Card } from '../components/common/Card';
@@ -42,7 +42,7 @@ import { useSubscriptionStore } from '../store';
 const ImportScreen: React.FC = () => {
   const { subscriptions, addSubscription, updateSubscription, deleteSubscription } =
     useSubscriptionStore();
-  const navigation = useNavigation<any>();
+  const navigation = useAppNavigation<'Import'>();
 
   const [importMode, setImportMode] = useState<ImportMode>('upsert');
   const [importText, setImportText] = useState('');
diff --git a/src/screens/SegmentDetailScreen.tsx b/src/screens/SegmentDetailScreen.tsx
index 023b0046..a87df9c1 100644
--- a/src/screens/SegmentDetailScreen.tsx
+++ b/src/screens/SegmentDetailScreen.tsx
@@ -5,12 +5,12 @@ import { useTheme } from '../theme/useTheme';
 import { Button } from '../components/common/Button';
 import { SegmentRuleBuilder } from '../components/segments/SegmentRuleBuilder';
 import { SegmentRule } from '../types/segment';
-import { useRoute, useNavigation } from '@react-navigation/native';
+import { useAppRoute, useAppNavigation } from '../navigation/types';
 
 export const SegmentDetailScreen: React.FC = () => {
   const theme = useTheme();
-  const route = useRoute<any>();
-  const navigation = useNavigation();
+  const route = useAppRoute<'SegmentDetail'>();
+  const navigation = useAppNavigation<'SegmentDetail'>();
   const { segmentId } = route.params;
   const { segments, addSegment, updateSegment } = useSegmentStore();
 
diff --git a/src/screens/SegmentManagementScreen.tsx b/src/screens/SegmentManagementScreen.tsx
index 42941907..aa277a55 100644
--- a/src/screens/SegmentManagementScreen.tsx
+++ b/src/screens/SegmentManagementScreen.tsx
@@ -9,11 +9,11 @@ import { useTheme } from '../theme/useTheme';
 import { Card } from '../components/common/Card';
 import { Button } from '../components/common/Button';
 import { SegmentOverlapAnalysis } from '../components/segments/SegmentOverlapAnalysis';
-import { useNavigation } from '@react-navigation/native';
+import { useAppNavigation } from '../navigation/types';
 
 export const SegmentManagementScreen: React.FC = () => {
   const theme = useTheme();
-  const navigation = useNavigation<any>();
+  const navigation = useAppNavigation<'SegmentManagement'>();
   const { segments, deleteSegment } = useSegmentStore();
   const { subscriptions } = useSubscriptionStore();
   const { user } = useUserStore();
diff --git a/src/screens/UsageDashboard.tsx b/src/screens/UsageDashboard.tsx
index 99e7b9b1..c2a9a3fb 100644
--- a/src/screens/UsageDashboard.tsx
+++ b/src/screens/UsageDashboard.tsx
@@ -1,6 +1,6 @@
 import React, { useEffect, useMemo } from 'react';
 import { View, Text, StyleSheet, ScrollView, TouchableOpacity, SafeAreaView } from 'react-native';
-import { useRoute, useNavigation } from '@react-navigation/native';
+import { useAppRoute, useAppNavigation } from '../navigation/types';
 import { colors, spacing, typography, borderRadius, shadows } from '../utils/constants';
 import { useUsageStore } from '../store/usageStore';
 import { QuotaMetric, QuotaStatus } from '../types/usage';
@@ -14,9 +14,9 @@ const METRIC_LABELS: Record<QuotaMetric, { label: string; unit: string }> = {
 };
 
 const UsageDashboard: React.FC = () => {
-  const route = useRoute<any>();
-  const navigation = useNavigation();
-  const { subscriptionId, planId = 'free', name } = route.params || {};
+  const route = useAppRoute<'UsageDashboard'>();
+  const navigation = useAppNavigation<'UsageDashboard'>();
+  const { subscriptionId, planId = 'free', name } = route.params ?? {};
   const { fetchUsage, getCurrentPeriodConsumption } = useUsageStore();
 
   useEffect(() => {
diff --git a/src/services/auditIntegration.ts b/src/services/auditIntegration.ts
index e901521e..66cd2f34 100644
--- a/src/services/auditIntegration.ts
+++ b/src/services/auditIntegration.ts
@@ -10,8 +10,19 @@ import type {
   AuditSeverity,
   ComplianceAuditReport,
 } from '../../backend/services/shared/auditTypes';
+import { env } from '../config/env';
+import { randomBytes } from 'crypto';
 
-const AUDIT_HMAC_SECRET = process.env['AUDIT_HMAC_SECRET'] ?? 'subtrackr-audit-secret';
+function getAuditSecret(): string {
+  if (env.AUDIT_HMAC_SECRET) {
+    return env.AUDIT_HMAC_SECRET;
+  }
+  // Generate a random secret for development if not provided
+  // This secret will be regenerated on each app restart, which is fine for dev
+  return randomBytes(32).toString('hex');
+}
+
+const AUDIT_HMAC_SECRET = getAuditSecret();
 
 const alertingService = new AlertingService();