diff --git a/app/(auth)/purchase.tsx b/app/(auth)/purchase.tsx
index 04eeba0..814e784 100644
--- a/app/(auth)/purchase.tsx
+++ b/app/(auth)/purchase.tsx
@@ -21,8 +21,8 @@ const STRIPE_API_URL = 'https://wellnuo.smartlaunchhub.com/api/stripe';
 
 const STARTER_KIT = {
   name: 'WellNuo Starter Kit',
-  price: '$249',
-  priceValue: 249,
+  price: '$399',
+  priceValue: 399,
 };
 
 export default function PurchaseScreen() {
@@ -260,7 +260,7 @@ export default function PurchaseScreen() {
           <Text style={styles.productPrice}>{STARTER_KIT.price}</Text>
 
           <Text style={styles.productDescription}>
-            4 smart sensors that easily plug into any outlet and set up through the app in minutes
+            5 smart sensors that easily plug into any outlet and set up through the app in minutes
           </Text>
 
           {/* Security Badge */}
@@ -282,7 +282,7 @@ export default function PurchaseScreen() {
             ) : (
               <>
                 <Ionicons name="card" size={20} color={AppColors.white} />
-                <Text style={styles.purchaseButtonText}>Buy Now - {STARTER_KIT.price}</Text>
+                <Text style={styles.purchaseButtonText}>Buy Now</Text>
               </>
             )}
           </TouchableOpacity>
diff --git a/app/(auth)/verify-otp.tsx b/app/(auth)/verify-otp.tsx
index b00816f..8744f01 100644
--- a/app/(auth)/verify-otp.tsx
+++ b/app/(auth)/verify-otp.tsx
@@ -185,6 +185,17 @@ export default function VerifyOTPScreen() {
     const success = await verifyOtp(email, codeToVerify);
 
     if (success) {
+      // If user has invite code, try to accept it (silent - don't block flow)
+      if (inviteCode) {
+        console.log('[VerifyOTP] Accepting invite code:', inviteCode);
+        const inviteResult = await api.acceptInvitation(inviteCode);
+        if (inviteResult.ok) {
+          console.log('[VerifyOTP] Invite code accepted:', inviteResult.data?.message);
+        } else {
+          console.warn('[VerifyOTP] Failed to accept invite code:', inviteResult.error?.message);
+          // Don't block - continue with registration flow
+        }
+      }
       await navigateAfterSuccess();
       return;
     }
diff --git a/app/(tabs)/beneficiaries/[id]/purchase.tsx b/app/(tabs)/beneficiaries/[id]/purchase.tsx
index 373a096..e77d3b2 100644
--- a/app/(tabs)/beneficiaries/[id]/purchase.tsx
+++ b/app/(tabs)/beneficiaries/[id]/purchase.tsx
@@ -32,9 +32,9 @@ const STRIPE_API_URL = 'https://wellnuo.smartlaunchhub.com/api/stripe';
 
 const STARTER_KIT = {
   name: 'WellNuo Starter Kit',
-  price: '$249',
-  priceValue: 249,
-  description: '4 smart sensors that easily plug into any outlet and set up through the app in minutes',
+  price: '$399',
+  priceValue: 399,
+  description: '5 smart sensors that easily plug into any outlet and set up through the app in minutes',
 };
 
 export default function PurchaseScreen() {
@@ -245,7 +245,7 @@ export default function PurchaseScreen() {
             ) : (
               <>
                 <Ionicons name="card" size={20} color={AppColors.white} />
-                <Text style={styles.buyButtonText}>Buy Now — {STARTER_KIT.price}</Text>
+                <Text style={styles.buyButtonText}>Buy Now</Text>
               </>
             )}
           </TouchableOpacity>
diff --git a/backend/scripts/setup-stripe-products.js b/backend/scripts/setup-stripe-products.js
index 4bc97c5..9a52af2 100644
--- a/backend/scripts/setup-stripe-products.js
+++ b/backend/scripts/setup-stripe-products.js
@@ -24,16 +24,16 @@ async function setupStripeProducts() {
     });
     console.log(`✓ Product created: ${starterKit.id}`);
 
-    // Create price for Starter Kit ($249 one-time)
+    // Create price for Starter Kit ($399 one-time)
     const starterKitPrice = await stripe.prices.create({
       product: starterKit.id,
-      unit_amount: 24900, // $249.00
+      unit_amount: 39900, // $399.00
       currency: 'usd',
       metadata: {
         display_name: 'Starter Kit'
       }
     });
-    console.log(`✓ Price created: ${starterKitPrice.id} ($249.00)\n`);
+    console.log(`✓ Price created: ${starterKitPrice.id} ($399.00)\n`);
 
     // 2. Create Premium Subscription product
     console.log('Creating Premium Subscription product...');
diff --git a/backend/src/config/stripe.js b/backend/src/config/stripe.js
index 791e0e0..0b524c7 100644
--- a/backend/src/config/stripe.js
+++ b/backend/src/config/stripe.js
@@ -9,7 +9,7 @@ const PRODUCTS = {
   STARTER_KIT: {
     name: 'WellNuo Starter Kit',
     description: '2x Motion Sensors + 1x Door Sensor + 1x Hub',
-    price: 24900, // $249.00 in cents
+    price: 39900, // $399.00 in cents
     type: 'one_time'
   },
   PREMIUM_SUBSCRIPTION: {
diff --git a/components/screens/auth-purchase/PurchaseScreen.native.tsx b/components/screens/auth-purchase/PurchaseScreen.native.tsx
index 04eeba0..814e784 100644
--- a/components/screens/auth-purchase/PurchaseScreen.native.tsx
+++ b/components/screens/auth-purchase/PurchaseScreen.native.tsx
@@ -21,8 +21,8 @@ const STRIPE_API_URL = 'https://wellnuo.smartlaunchhub.com/api/stripe';
 
 const STARTER_KIT = {
   name: 'WellNuo Starter Kit',
-  price: '$249',
-  priceValue: 249,
+  price: '$399',
+  priceValue: 399,
 };
 
 export default function PurchaseScreen() {
@@ -260,7 +260,7 @@ export default function PurchaseScreen() {
           <Text style={styles.productPrice}>{STARTER_KIT.price}</Text>
 
           <Text style={styles.productDescription}>
-            4 smart sensors that easily plug into any outlet and set up through the app in minutes
+            5 smart sensors that easily plug into any outlet and set up through the app in minutes
           </Text>
 
           {/* Security Badge */}
@@ -282,7 +282,7 @@ export default function PurchaseScreen() {
             ) : (
               <>
                 <Ionicons name="card" size={20} color={AppColors.white} />
-                <Text style={styles.purchaseButtonText}>Buy Now - {STARTER_KIT.price}</Text>
+                <Text style={styles.purchaseButtonText}>Buy Now</Text>
               </>
             )}
           </TouchableOpacity>
diff --git a/components/screens/auth-purchase/PurchaseScreen.web.tsx b/components/screens/auth-purchase/PurchaseScreen.web.tsx
index 90ab36d..62b5ca3 100644
--- a/components/screens/auth-purchase/PurchaseScreen.web.tsx
+++ b/components/screens/auth-purchase/PurchaseScreen.web.tsx
@@ -22,8 +22,8 @@ import { hasBeneficiaryDevices } from '@/services/BeneficiaryDetailController';
 
 const STARTER_KIT = {
     name: 'WellNuo Starter Kit',
-    price: '$249',
-    priceValue: 249,
+    price: '$399',
+    priceValue: 399,
 };
 
 export default function PurchaseScreen() {
@@ -158,7 +158,7 @@ export default function PurchaseScreen() {
                     <Text style={styles.productPrice}>{STARTER_KIT.price}</Text>
 
                     <Text style={styles.productDescription}>
-                        4 smart sensors that easily plug into any outlet and set up through the app in minutes
+                        5 smart sensors that easily plug into any outlet and set up through the app in minutes
                     </Text>
 
                     {/* Security Badge */}
@@ -180,7 +180,7 @@ export default function PurchaseScreen() {
                         ) : (
                             <>
                                 <Ionicons name="card" size={20} color={AppColors.white} />
-                                <Text style={styles.purchaseButtonText}>Buy Now - {STARTER_KIT.price}</Text>
+                                <Text style={styles.purchaseButtonText}>Buy Now</Text>
                             </>
                         )}
                     </TouchableOpacity>
diff --git a/components/screens/purchase/PurchaseScreen.native.tsx b/components/screens/purchase/PurchaseScreen.native.tsx
index 373a096..e77d3b2 100644
--- a/components/screens/purchase/PurchaseScreen.native.tsx
+++ b/components/screens/purchase/PurchaseScreen.native.tsx
@@ -32,9 +32,9 @@ const STRIPE_API_URL = 'https://wellnuo.smartlaunchhub.com/api/stripe';
 
 const STARTER_KIT = {
   name: 'WellNuo Starter Kit',
-  price: '$249',
-  priceValue: 249,
-  description: '4 smart sensors that easily plug into any outlet and set up through the app in minutes',
+  price: '$399',
+  priceValue: 399,
+  description: '5 smart sensors that easily plug into any outlet and set up through the app in minutes',
 };
 
 export default function PurchaseScreen() {
@@ -245,7 +245,7 @@ export default function PurchaseScreen() {
             ) : (
               <>
                 <Ionicons name="card" size={20} color={AppColors.white} />
-                <Text style={styles.buyButtonText}>Buy Now — {STARTER_KIT.price}</Text>
+                <Text style={styles.buyButtonText}>Buy Now</Text>
               </>
             )}
           </TouchableOpacity>
diff --git a/components/screens/purchase/PurchaseScreen.web.tsx b/components/screens/purchase/PurchaseScreen.web.tsx
index 9d1989c..87d1b5a 100644
--- a/components/screens/purchase/PurchaseScreen.web.tsx
+++ b/components/screens/purchase/PurchaseScreen.web.tsx
@@ -33,9 +33,9 @@ import { hasBeneficiaryDevices } from '@/services/BeneficiaryDetailController';
 
 const STARTER_KIT = {
     name: 'WellNuo Starter Kit',
-    price: '$249',
-    priceValue: 249,
-    description: '4 smart sensors that easily plug into any outlet and set up through the app in minutes',
+    price: '$399',
+    priceValue: 399,
+    description: '5 smart sensors that easily plug into any outlet and set up through the app in minutes',
 };
 
 export default function PurchaseScreen() {
@@ -167,7 +167,7 @@ export default function PurchaseScreen() {
                         ) : (
                             <>
                                 <Ionicons name="card" size={20} color={AppColors.white} />
-                                <Text style={styles.buyButtonText}>Buy Now — {STARTER_KIT.price}</Text>
+                                <Text style={styles.buyButtonText}>Buy Now</Text>
                             </>
                         )}
                     </TouchableOpacity>
diff --git a/package-lock.json b/package-lock.json
index 9d8f983..4218322 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9,6 +9,7 @@
       "version": "1.0.0",
       "dependencies": {
         "@expo/vector-icons": "^15.0.3",
+        "@orbital-systems/react-native-esp-idf-provisioning": "^0.5.0",
         "@react-native-async-storage/async-storage": "^2.2.0",
         "@react-navigation/bottom-tabs": "^7.4.0",
         "@react-navigation/elements": "^2.6.3",
@@ -21,7 +22,6 @@
         "expo-camera": "~17.0.10",
         "expo-clipboard": "~8.0.8",
         "expo-constants": "~18.0.12",
-        "expo-crypto": "~15.0.8",
         "expo-file-system": "~19.0.21",
         "expo-font": "~14.0.10",
         "expo-haptics": "~15.0.8",
@@ -43,6 +43,7 @@
         "react-native": "0.81.5",
         "react-native-fs": "^2.20.0",
         "react-native-gesture-handler": "~2.28.0",
+        "react-native-get-random-values": "^2.0.0",
         "react-native-reanimated": "~4.1.1",
         "react-native-root-toast": "^4.0.1",
         "react-native-safe-area-context": "~5.6.0",
@@ -4699,6 +4700,46 @@
         "node": ">=10"
       }
     },
+    "node_modules/@orbital-systems/react-native-esp-idf-provisioning": {
+      "version": "0.5.0",
+      "resolved": "https://registry.npmjs.org/@orbital-systems/react-native-esp-idf-provisioning/-/react-native-esp-idf-provisioning-0.5.0.tgz",
+      "integrity": "sha512-CDwWVkRCgZF4zLWR4F/R1G5JzXPBxS5leURpYnKhpoKz9xJzxixa8gMJZes/zUYeSoDDHpIZo15YrorCJuQjFA==",
+      "license": "MIT",
+      "dependencies": {
+        "buffer": "^6.0.3"
+      },
+      "engines": {
+        "node": ">= 18.0.0"
+      },
+      "peerDependencies": {
+        "react": "*",
+        "react-native": "*"
+      }
+    },
+    "node_modules/@orbital-systems/react-native-esp-idf-provisioning/node_modules/buffer": {
+      "version": "6.0.3",
+      "resolved": "https://registry.npmjs.org/buffer/-/buffer-6.0.3.tgz",
+      "integrity": "sha512-FTiCpNxtwiZZHEZbcbTIcZjERVICn9yq/pDFkTl95/AxzD1naBctN7YO68riM/gLSDY7sdrMby8hofADYuuqOA==",
+      "funding": [
+        {
+          "type": "github",
+          "url": "https://github.com/sponsors/feross"
+        },
+        {
+          "type": "patreon",
+          "url": "https://www.patreon.com/feross"
+        },
+        {
+          "type": "consulting",
+          "url": "https://feross.org/support"
+        }
+      ],
+      "license": "MIT",
+      "dependencies": {
+        "base64-js": "^1.3.1",
+        "ieee754": "^1.2.1"
+      }
+    },
     "node_modules/@pkgjs/parseargs": {
       "version": "0.11.0",
       "resolved": "https://registry.npmjs.org/@pkgjs/parseargs/-/parseargs-0.11.0.tgz",
@@ -10699,18 +10740,6 @@
         "react-native": "*"
       }
     },
-    "node_modules/expo-crypto": {
-      "version": "15.0.8",
-      "resolved": "https://registry.npmjs.org/expo-crypto/-/expo-crypto-15.0.8.tgz",
-      "integrity": "sha512-aF7A914TB66WIlTJvl5J6/itejfY78O7dq3ibvFltL9vnTALJ/7LYHvLT4fwmx9yUNS6ekLBtDGWivFWnj2Fcw==",
-      "license": "MIT",
-      "dependencies": {
-        "base64-js": "^1.3.0"
-      },
-      "peerDependencies": {
-        "expo": "*"
-      }
-    },
     "node_modules/expo-file-system": {
       "version": "19.0.21",
       "resolved": "https://registry.npmjs.org/expo-file-system/-/expo-file-system-19.0.21.tgz",
@@ -11409,6 +11438,12 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/fast-base64-decode": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/fast-base64-decode/-/fast-base64-decode-1.0.0.tgz",
+      "integrity": "sha512-qwaScUgUGBYeDNRnbc/KyllVU88Jk1pRHPStuF/lO7B0/RTRLj7U0lkdTAutlBblY08rwZDff6tNU9cjv6j//Q==",
+      "license": "MIT"
+    },
     "node_modules/fast-deep-equal": {
       "version": "3.1.3",
       "resolved": "https://registry.npmjs.org/fast-deep-equal/-/fast-deep-equal-3.1.3.tgz",
@@ -18789,6 +18824,18 @@
         "react-native": "*"
       }
     },
+    "node_modules/react-native-get-random-values": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/react-native-get-random-values/-/react-native-get-random-values-2.0.0.tgz",
+      "integrity": "sha512-wx7/aPqsUIiWsG35D+MsUJd8ij96e3JKddklSdrdZUrheTx89gPtz3Q2yl9knBArj5u26Cl23T88ai+Q0vypdQ==",
+      "license": "MIT",
+      "dependencies": {
+        "fast-base64-decode": "^1.0.0"
+      },
+      "peerDependencies": {
+        "react-native": ">=0.81"
+      }
+    },
     "node_modules/react-native-is-edge-to-edge": {
       "version": "1.2.1",
       "resolved": "https://registry.npmjs.org/react-native-is-edge-to-edge/-/react-native-is-edge-to-edge-1.2.1.tgz",
diff --git a/package.json b/package.json
index e6cf09c..68fb7fe 100644
--- a/package.json
+++ b/package.json
@@ -12,6 +12,7 @@
   },
   "dependencies": {
     "@expo/vector-icons": "^15.0.3",
+    "@orbital-systems/react-native-esp-idf-provisioning": "^0.5.0",
     "@react-native-async-storage/async-storage": "^2.2.0",
     "@react-navigation/bottom-tabs": "^7.4.0",
     "@react-navigation/elements": "^2.6.3",
@@ -24,7 +25,6 @@
     "expo-camera": "~17.0.10",
     "expo-clipboard": "~8.0.8",
     "expo-constants": "~18.0.12",
-    "expo-crypto": "~15.0.8",
     "expo-file-system": "~19.0.21",
     "expo-font": "~14.0.10",
     "expo-haptics": "~15.0.8",
@@ -46,6 +46,7 @@
     "react-native": "0.81.5",
     "react-native-fs": "^2.20.0",
     "react-native-gesture-handler": "~2.28.0",
+    "react-native-get-random-values": "^2.0.0",
     "react-native-reanimated": "~4.1.1",
     "react-native-root-toast": "^4.0.1",
     "react-native-safe-area-context": "~5.6.0",
diff --git a/services/api.ts b/services/api.ts
index dd651a0..c37e425 100644
--- a/services/api.ts
+++ b/services/api.ts
@@ -1,8 +1,8 @@
 import type { ApiError, ApiResponse, AuthResponse, Beneficiary, BeneficiaryDashboardData, ChatResponse, DashboardSingleResponse, NotificationSettings } from '@/types';
-import * as Crypto from 'expo-crypto';
 import { File } from 'expo-file-system';
 import * as SecureStore from 'expo-secure-store';
 import AsyncStorage from '@react-native-async-storage/async-storage';
+import 'react-native-get-random-values'; // Polyfill for crypto.getRandomValues
 
 // Callback for handling unauthorized responses (401)
 let onUnauthorizedCallback: (() => void) | null = null;
@@ -67,7 +67,9 @@ class ApiService {
   }
 
   private generateNonce(): string {
-    const randomBytes = Crypto.getRandomBytes(16);
+    // Use Web Crypto API (polyfilled by react-native-get-random-values)
+    const randomBytes = new Uint8Array(16);
+    crypto.getRandomValues(randomBytes);
     return Array.from(randomBytes)
       .map(b => b.toString(16).padStart(2, '0'))
       .join('');
@@ -1080,6 +1082,51 @@ class ApiService {
     }
   }
 
+  // Accept invitation code
+  async acceptInvitation(code: string): Promise<ApiResponse<{
+    success: boolean;
+    message: string;
+    beneficiary?: {
+      id: number;
+      firstName: string | null;
+      lastName: string | null;
+      email: string | null;
+    };
+    role?: string;
+  }>> {
+    const token = await this.getToken();
+    if (!token) {
+      return { ok: false, error: { message: 'Not authenticated', code: 'UNAUTHORIZED' } };
+    }
+
+    try {
+      const response = await fetch(`${WELLNUO_API_URL}/invitations/accept`, {
+        method: 'POST',
+        headers: {
+          'Authorization': `Bearer ${token}`,
+          'Content-Type': 'application/json',
+        },
+        body: JSON.stringify({ code }),
+      });
+
+      const data = await response.json();
+
+      if (response.ok) {
+        return { data, ok: true };
+      }
+
+      return {
+        ok: false,
+        error: { message: data.error || 'Failed to accept invitation' },
+      };
+    } catch (error) {
+      return {
+        ok: false,
+        error: { message: 'Network error. Please check your connection.' },
+      };
+    }
+  }
+
   // Activate equipment for beneficiary (saves to server)
   async activateBeneficiary(beneficiaryId: number, serialNumber: string): Promise<ApiResponse<{
     success: boolean;
diff --git a/services/espProvisioning.ts b/services/espProvisioning.ts
index 9f9b3c6..a21e361 100644
--- a/services/espProvisioning.ts
+++ b/services/espProvisioning.ts
@@ -6,27 +6,23 @@
  *
  * Uses @orbital-systems/react-native-esp-idf-provisioning which wraps
  * Espressif's official provisioning libraries.
+ *
+ * NOTE: This module requires a development build. In Expo Go, a mock
+ * implementation is used that returns empty results.
  */
 
-import {
-  ESPProvisionManager,
-  ESPDevice,
-  ESPTransport,
-  ESPSecurity,
-  type ESPWifi,
-} from '@orbital-systems/react-native-esp-idf-provisioning';
 import { Platform, PermissionsAndroid, Alert } from 'react-native';
+import Constants from 'expo-constants';
+
+// Check if we're running in Expo Go (no native modules available)
+const isExpoGo = Constants.appOwnership === 'expo';
 
 // WellNuo device prefix (matches WP_xxx_xxxxxx pattern)
 const WELLNUO_DEVICE_PREFIX = 'WP_';
 
-// Security mode - most ESP32 devices use secure or secure2
-// Try unsecure first if device doesn't have proof-of-possession
-const DEFAULT_SECURITY = ESPSecurity.unsecure;
-
 export interface WellNuoDevice {
   name: string;
-  device: ESPDevice;
+  device: any; // ESPDevice when native module available
   wellId?: string;      // Extracted from name: WP_<wellId>_<mac>
   macPart?: string;     // Last part of MAC address
 }
@@ -37,14 +33,44 @@ export interface WifiNetwork {
   auth: string;
 }
 
+// Dynamic import types - will be null in Expo Go
+let ESPProvisionManager: any = null;
+let ESPTransport: any = null;
+let ESPSecurity: any = null;
+
+// Try to load native module only in development builds
+if (!isExpoGo) {
+  try {
+    const espModule = require('@orbital-systems/react-native-esp-idf-provisioning');
+    ESPProvisionManager = espModule.ESPProvisionManager;
+    ESPTransport = espModule.ESPTransport;
+    ESPSecurity = espModule.ESPSecurity;
+    console.log('[ESP] Native provisioning module loaded');
+  } catch (e) {
+    console.warn('[ESP] Native provisioning module not available:', e);
+  }
+}
+
 class ESPProvisioningService {
-  private connectedDevice: ESPDevice | null = null;
+  private connectedDevice: any | null = null;
   private isScanning = false;
 
+  /**
+   * Check if ESP provisioning is available (development build only)
+   */
+  isAvailable(): boolean {
+    return ESPProvisionManager !== null;
+  }
+
   /**
    * Request necessary permissions for BLE on Android
    */
   async requestPermissions(): Promise<boolean> {
+    if (!this.isAvailable()) {
+      console.warn('[ESP] Provisioning not available in Expo Go');
+      return false;
+    }
+
     if (Platform.OS !== 'android') {
       return true;
     }
@@ -76,6 +102,16 @@ class ESPProvisioningService {
    * Returns list of devices matching WP_xxx_xxxxxx pattern
    */
   async scanForDevices(timeoutMs = 10000): Promise<WellNuoDevice[]> {
+    if (!this.isAvailable()) {
+      console.warn('[ESP] Scan not available - running in Expo Go');
+      Alert.alert(
+        'Development Build Required',
+        'WiFi provisioning requires a development build. This feature is not available in Expo Go.',
+        [{ text: 'OK' }]
+      );
+      return [];
+    }
+
     if (this.isScanning) {
       console.warn('[ESP] Already scanning, please wait');
       return [];
@@ -93,12 +129,12 @@ class ESPProvisioningService {
       const devices = await ESPProvisionManager.searchESPDevices(
         WELLNUO_DEVICE_PREFIX,
         ESPTransport.ble,
-        DEFAULT_SECURITY
+        ESPSecurity.unsecure
       );
 
       console.log(`[ESP] Found ${devices.length} WellNuo device(s)`);
 
-      return devices.map((device: ESPDevice) => {
+      return devices.map((device: any) => {
         // Parse device name: WP_<wellId>_<macPart>
         const parts = device.name?.split('_') || [];
         return {
@@ -122,9 +158,14 @@ class ESPProvisioningService {
    * @param proofOfPossession - Optional PoP for secure devices
    */
   async connect(
-    device: ESPDevice,
+    device: any,
     proofOfPossession?: string
   ): Promise<boolean> {
+    if (!this.isAvailable()) {
+      console.warn('[ESP] Connect not available - running in Expo Go');
+      return false;
+    }
+
     if (this.connectedDevice) {
       console.warn('[ESP] Already connected, disconnecting first...');
       await this.disconnect();
@@ -148,6 +189,11 @@ class ESPProvisioningService {
    * Scan for available WiFi networks through connected device
    */
   async scanWifiNetworks(): Promise<WifiNetwork[]> {
+    if (!this.isAvailable()) {
+      console.warn('[ESP] WiFi scan not available - running in Expo Go');
+      return [];
+    }
+
     if (!this.connectedDevice) {
       throw new Error('Not connected to any device');
     }
@@ -159,7 +205,7 @@ class ESPProvisioningService {
 
       console.log(`[ESP] Found ${wifiList.length} WiFi network(s)`);
 
-      return wifiList.map((wifi: ESPWifi) => ({
+      return wifiList.map((wifi: any) => ({
         ssid: wifi.ssid,
         rssi: wifi.rssi,
         auth: this.getAuthModeName(wifi.auth),
@@ -176,6 +222,11 @@ class ESPProvisioningService {
    * @param password - WiFi password
    */
   async provisionWifi(ssid: string, password: string): Promise<boolean> {
+    if (!this.isAvailable()) {
+      console.warn('[ESP] Provisioning not available - running in Expo Go');
+      return false;
+    }
+
     if (!this.connectedDevice) {
       throw new Error('Not connected to any device');
     }
@@ -246,4 +297,4 @@ class ESPProvisioningService {
 export const espProvisioning = new ESPProvisioningService();
 
 // Export types for components
-export type { ESPDevice };
+export type ESPDevice = any;
diff --git a/services/sherpaTTS.ts b/services/sherpaTTS.ts
index e79c1d8..a7c20b9 100644
--- a/services/sherpaTTS.ts
+++ b/services/sherpaTTS.ts
@@ -1,10 +1,13 @@
 /**
- * Sherpa TTS Service - STUB for Expo Go development
- * The real implementation requires native modules which don't work in Expo Go
- * This stub returns "not available" so the app falls back to expo-speech
+ * Sherpa TTS Service - Native implementation for offline Text-to-Speech
+ * Uses react-native-sherpa-onnx-offline-tts with Piper VITS models
  */
 
-// Available Piper neural voices - kept for type compatibility
+import { Platform, NativeModules, NativeEventEmitter } from 'react-native';
+import * as FileSystem from 'expo-file-system';
+import { Asset } from 'expo-asset';
+
+// Available Piper neural voices
 export interface PiperVoice {
   id: string;
   name: string;
@@ -25,23 +28,57 @@ export const AVAILABLE_VOICES: PiperVoice[] = [
     gender: 'female',
     accent: 'US',
   },
+  {
+    id: 'ryan',
+    name: 'Ryan',
+    description: 'American Male (Natural)',
+    modelDir: 'vits-piper-en_US-ryan-medium',
+    onnxFile: 'en_US-ryan-medium.onnx',
+    gender: 'male',
+    accent: 'US',
+  },
+  {
+    id: 'alba',
+    name: 'Alba',
+    description: 'British Female',
+    modelDir: 'vits-piper-en_GB-alba-medium',
+    onnxFile: 'en_GB-alba-medium.onnx',
+    gender: 'female',
+    accent: 'UK',
+  },
 ];
 
 interface SherpaTTSState {
   initialized: boolean;
   initializing: boolean;
   error: string | null;
+  currentVoice: PiperVoice;
+}
+
+// Check if native module is available
+const TTSManager = NativeModules.TTSManager;
+const NATIVE_MODULE_AVAILABLE = !!TTSManager;
+
+let ttsManagerEmitter: NativeEventEmitter | null = null;
+if (NATIVE_MODULE_AVAILABLE) {
+  ttsManagerEmitter = new NativeEventEmitter(TTSManager);
 }
 
 let currentState: SherpaTTSState = {
   initialized: false,
   initializing: false,
-  error: 'Sherpa TTS disabled for Expo Go development',
+  error: null,
+  currentVoice: AVAILABLE_VOICES[0],
 };
 
 // State listeners
 const stateListeners: ((state: SherpaTTSState) => void)[] = [];
 
+function updateState(updates: Partial<SherpaTTSState>) {
+  currentState = { ...currentState, ...updates };
+  notifyListeners();
+}
+
 function notifyListeners() {
   stateListeners.forEach(listener => listener({ ...currentState }));
 }
@@ -59,12 +96,179 @@ export function getState(): SherpaTTSState {
   return { ...currentState };
 }
 
-// Stub implementations - always return false/unavailable
-export async function initializeSherpaTTS(): Promise<boolean> {
-  console.log('[SherpaTTS STUB] Sherpa TTS disabled for Expo Go - using expo-speech instead');
-  return false;
+/**
+ * Copy bundled TTS model assets to document directory for native access
+ * NOTE: Temporarily disabled dynamic requires for Metro bundler compatibility
+ */
+async function copyModelToDocuments(voice: PiperVoice): Promise<string | null> {
+  // TEMP: Skip dynamic requires - TTS models will be loaded differently
+  console.log('[SherpaTTS] copyModelToDocuments temporarily disabled');
+  return null;
+
+  /* DISABLED - dynamic requires don't work with Metro bundler
+  try {
+    const destDir = `${FileSystem.documentDirectory}tts-models/${voice.modelDir}`;
+    const onnxPath = `${destDir}/${voice.onnxFile}`;
+
+    // Check if already copied
+    const onnxInfo = await FileSystem.getInfoAsync(onnxPath);
+    if (onnxInfo.exists) {
+      console.log('[SherpaTTS] Model already exists at:', destDir);
+      return destDir;
+    }
+
+    console.log('[SherpaTTS] Copying model to documents directory...');
+
+    // Create destination directory
+    await FileSystem.makeDirectoryAsync(destDir, { intermediates: true });
+
+    // For Expo, we need to copy from assets
+    // The models are in assets/tts-models/
+    const assetBase = `../assets/tts-models/${voice.modelDir}`;
+
+    // Copy main ONNX file
+    const onnxAsset = Asset.fromModule(require(`../assets/tts-models/${voice.modelDir}/${voice.onnxFile}`));
+    await onnxAsset.downloadAsync();
+    if (onnxAsset.localUri) {
+      await FileSystem.copyAsync({
+        from: onnxAsset.localUri,
+        to: onnxPath,
+      });
+    }
+
+    // Copy tokens.txt
+    const tokensAsset = Asset.fromModule(require(`../assets/tts-models/${voice.modelDir}/tokens.txt`));
+    await tokensAsset.downloadAsync();
+    if (tokensAsset.localUri) {
+      await FileSystem.copyAsync({
+        from: tokensAsset.localUri,
+        to: `${destDir}/tokens.txt`,
+      });
+    }
+
+    // Copy espeak-ng-data directory
+    // This is more complex - need to copy entire directory
+    const espeakDestDir = `${destDir}/espeak-ng-data`;
+    await FileSystem.makeDirectoryAsync(espeakDestDir, { intermediates: true });
+
+    // For now, we'll use the bundle path directly on iOS
+    console.log('[SherpaTTS] Model copied successfully');
+    return destDir;
+
+  } catch (error) {
+    console.error('[SherpaTTS] Error copying model:', error);
+    return null;
+  }
+  */
 }
 
+/**
+ * Get the path to bundled models (iOS bundle or Android assets)
+ */
+function getBundledModelPath(voice: PiperVoice): string | null {
+  if (Platform.OS === 'ios') {
+    // On iOS, assets are in the main bundle
+    const bundlePath = NativeModules.RNFSManager?.MainBundlePath || '';
+    if (!bundlePath) {
+      // Try to construct path from FileSystem
+      // Models should be copied during pod install or prebuild
+      return null;
+    }
+    return `${bundlePath}/assets/tts-models/${voice.modelDir}`;
+  } else if (Platform.OS === 'android') {
+    // On Android, assets are extracted to files dir
+    return `${FileSystem.documentDirectory}tts-models/${voice.modelDir}`;
+  }
+  return null;
+}
+
+/**
+ * Initialize Sherpa TTS with a specific voice model
+ */
+export async function initializeSherpaTTS(voice?: PiperVoice): Promise<boolean> {
+  if (!NATIVE_MODULE_AVAILABLE) {
+    console.log('[SherpaTTS] Native module not available (Expo Go mode)');
+    updateState({
+      initialized: false,
+      error: 'Native module not available - use native build'
+    });
+    return false;
+  }
+
+  if (currentState.initializing) {
+    console.log('[SherpaTTS] Already initializing...');
+    return false;
+  }
+
+  const selectedVoice = voice || currentState.currentVoice;
+  updateState({ initializing: true, error: null });
+
+  try {
+    console.log('[SherpaTTS] Initializing with voice:', selectedVoice.name);
+
+    // Get model paths
+    // For native build, models should be in the app bundle
+    // We use FileSystem.bundleDirectory on iOS
+    let modelBasePath: string;
+
+    if (Platform.OS === 'ios') {
+      // iOS: Models are copied to bundle during build
+      // Access via MainBundle
+      const mainBundle = await FileSystem.getInfoAsync(FileSystem.bundleDirectory || '');
+      if (mainBundle.exists) {
+        modelBasePath = `${FileSystem.bundleDirectory}assets/tts-models/${selectedVoice.modelDir}`;
+      } else {
+        // Fallback: try document directory
+        modelBasePath = `${FileSystem.documentDirectory}tts-models/${selectedVoice.modelDir}`;
+      }
+    } else {
+      // Android: Extract from assets to document directory
+      modelBasePath = `${FileSystem.documentDirectory}tts-models/${selectedVoice.modelDir}`;
+    }
+
+    // Check if model exists
+    const modelPath = `${modelBasePath}/${selectedVoice.onnxFile}`;
+    const tokensPath = `${modelBasePath}/tokens.txt`;
+    const dataDirPath = `${modelBasePath}/espeak-ng-data`;
+
+    console.log('[SherpaTTS] Model paths:', { modelPath, tokensPath, dataDirPath });
+
+    // Create config JSON for native module
+    const config = JSON.stringify({
+      modelPath,
+      tokensPath,
+      dataDirPath,
+    });
+
+    // Initialize native TTS
+    // Sample rate 22050, mono channel
+    TTSManager.initializeTTS(22050, 1, config);
+
+    updateState({
+      initialized: true,
+      initializing: false,
+      currentVoice: selectedVoice,
+      error: null
+    });
+
+    console.log('[SherpaTTS] Initialized successfully');
+    return true;
+
+  } catch (error) {
+    const errorMessage = error instanceof Error ? error.message : 'Unknown error';
+    console.error('[SherpaTTS] Initialization error:', errorMessage);
+    updateState({
+      initialized: false,
+      initializing: false,
+      error: errorMessage
+    });
+    return false;
+  }
+}
+
+/**
+ * Speak text using Sherpa TTS
+ */
 export async function speak(
   text: string,
   options?: {
@@ -75,30 +279,108 @@ export async function speak(
     onError?: (error: Error) => void;
   }
 ): Promise<void> {
-  options?.onError?.(new Error('Sherpa TTS disabled for Expo Go'));
+  if (!NATIVE_MODULE_AVAILABLE || !currentState.initialized) {
+    options?.onError?.(new Error('Sherpa TTS not initialized'));
+    return;
+  }
+
+  const speed = options?.speed ?? 1.0;
+  const speakerId = options?.speakerId ?? 0;
+
+  try {
+    options?.onStart?.();
+
+    await TTSManager.generateAndPlay(text, speakerId, speed);
+
+    options?.onDone?.();
+  } catch (error) {
+    const err = error instanceof Error ? error : new Error('TTS playback failed');
+    console.error('[SherpaTTS] Speak error:', err);
+    options?.onError?.(err);
+  }
 }
 
+/**
+ * Stop current speech playback
+ */
 export function stop(): void {
-  // No-op
+  if (NATIVE_MODULE_AVAILABLE && currentState.initialized) {
+    try {
+      TTSManager.deinitialize();
+      // Re-initialize after stop to be ready for next speech
+      setTimeout(() => {
+        if (currentState.currentVoice) {
+          initializeSherpaTTS(currentState.currentVoice);
+        }
+      }, 100);
+    } catch (error) {
+      console.error('[SherpaTTS] Stop error:', error);
+    }
+  }
 }
 
+/**
+ * Deinitialize and free resources
+ */
 export function deinitialize(): void {
-  // No-op
+  if (NATIVE_MODULE_AVAILABLE) {
+    try {
+      TTSManager.deinitialize();
+    } catch (error) {
+      console.error('[SherpaTTS] Deinitialize error:', error);
+    }
+  }
+  updateState({ initialized: false, error: null });
 }
 
+/**
+ * Check if Sherpa TTS is available (native module loaded)
+ */
 export function isAvailable(): boolean {
-  return false;
+  return NATIVE_MODULE_AVAILABLE && currentState.initialized;
 }
 
+/**
+ * Get current voice
+ */
 export function getCurrentVoice(): PiperVoice {
-  return AVAILABLE_VOICES[0];
+  return currentState.currentVoice;
 }
 
+/**
+ * Set and switch to a different voice
+ */
 export async function setVoice(voiceId: string): Promise<boolean> {
-  return false;
+  const voice = AVAILABLE_VOICES.find(v => v.id === voiceId);
+  if (!voice) {
+    console.error('[SherpaTTS] Voice not found:', voiceId);
+    return false;
+  }
+
+  // Deinitialize current and reinitialize with new voice
+  deinitialize();
+  return initializeSherpaTTS(voice);
 }
 
+/**
+ * Add listener for volume updates during playback
+ */
+export function addVolumeListener(callback: (volume: number) => void): (() => void) | null {
+  if (!ttsManagerEmitter) return null;
+
+  const subscription = ttsManagerEmitter.addListener('VolumeUpdate', (event) => {
+    callback(event.volume);
+  });
+
+  return () => subscription.remove();
+}
+
+/**
+ * Load saved voice preference
+ */
 export async function loadSavedVoice(): Promise<PiperVoice> {
+  // For now, just return default voice
+  // Could add AsyncStorage persistence later
   return AVAILABLE_VOICES[0];
 }
 
@@ -114,4 +396,5 @@ export default {
   getCurrentVoice,
   setVoice,
   loadSavedVoice,
+  addVolumeListener,
 };