secure-chat

P2P chat app built with Expo + React Native.

Supports two uplink modes:

• Online chat: peer discovery/signaling over WebSocket + P2P data channel
• Local chat: Bluetooth Low Energy (BLE) chat using react-native-ble-plx

Setup

npm install

Create .env in project root:

EXPO_PUBLIC_SIGNALING_URL=ws://<your-ip>:8080
# or
# EXPO_PUBLIC_SIGNALING_WS_URL=ws://<your-ip>:8080

The app reads either variable from services/env.ts.

Run

npx expo start

Expo Go not supported as BLE and WebRTC use native modules make a custom dev build. Use expo-prebuild or eas-cli to build.

Build and run on device/emulator:

npx expo run:android
# or
npx expo run:ios

Run lint:

npm run lint

Signaling Server

Check out secure-chat-signaling

BLE Notes

• BLE requires Bluetooth enabled and runtime permissions.
• For best reliability, test on two physical devices nearby.
• Current BLE service uses UART-like UUIDs inside services/chatSessionBluetooth.ts.
• If your peer peripheral uses different service/characteristic UUIDs, update:
  • CHAT_SERVICE_UUID
  • CHAT_TX_CHAR_UUID
  • CHAT_RX_CHAR_UUID

Project Scripts

• npm run android - build + run Android
• npm run ios - build + run iOS
• npm run web - web preview (limited for native features)
• npm run lint - lint project

Folder structure

• app/ - routes/screens (onboarding, user, chat)
• services/chatSession.ts - internet/WebRTC session logic
• services/chatSessionBluetooth.ts - BLE session logic
• store/ - Zustand stores for user/chat/session state

secure-chat.mp4