BitChat for Flipper Zero

A decentralized Bluetooth mesh messaging app ported to Flipper Zero.

Made by lalo with <3 for jack

Features

• Bluetooth Mesh Network: Send messages to nearby Flipper devices
• Multi-hop Relay: Messages relay through nearby devices (max 7 hops)
• Noise Protocol Encryption: End-to-end encrypted private messages
• No Internet Required: Works completely offline
• Peer Discovery: Automatic discovery of nearby BitChat users
• Intuitive UI: Clean, optimized interface for Flipper's 128x64 display
  • Scrollable message history (up to 50 messages)
  • Real-time peer count indicator
  • Connection status with visual feedback
  • Easy text input with Flipper's keyboard
  • Smooth navigation between views
  • Visual and haptic feedback for actions

Architecture

This is a C port of the BitChat protocol, implementing:

• Binary protocol encoder/decoder
• Noise XX handshake for encryption
• BLE transport layer using Flipper's BLE API
• Simple message storage and UI

Building

Using ufbt (recommended):

cd flipperBITCHAT
ufbt

Installing

ufbt launch

Or copy the built .fap file to your Flipper's apps/Bluetooth directory.

Usage

1. Launch BitChat from Applications > Bluetooth
2. First Time Setup: Enter your nickname when prompted
3. View Messages: Scroll through chat history with Up/Down buttons
4. Send Messages: Press OK button to open keyboard, type and send
5. Monitor Status: Check connection indicator (●) and peer count in header
6. Navigation: Press Back to return to previous view or exit

Interface Guide

Main Chat View:

• Header shows connection status (●/○) and peer count
• Message area displays conversation history
• Your messages are marked with ">"
• Use Up/Down to scroll through messages
• Press OK to compose new message
• Press Back to exit

Message Input:

• Enter your message using Flipper keyboard
• Press OK to send
• Press Back to cancel

Status Indicators:

• ● (Filled circle) = Connected to BLE mesh
• ○ (Empty circle) = Disconnected
• Number shows active peers nearby

Protocol Compatibility

This implementation is compatible with the main BitChat app (iOS/macOS) and uses the same:

• Binary wire format (v1)
• Noise XX handshake pattern
• BLE service UUID: F47B5E2D-4A9E-4C5A-9B3F-8E1D2C3A4B5C

UI/UX Design

The interface is designed specifically for the Flipper Zero's 128x64 monochrome display:

Design Principles:

• Clarity: High contrast, readable fonts (Primary & Secondary)
• Efficiency: Minimal button presses to perform actions
• Feedback: Visual (status icons) and haptic (vibrations) confirmations
• Simplicity: Focus on core messaging functionality
• Navigation: Intuitive back-button behavior for easy flow

View Structure:

Nickname Setup → Main Chat View ⇄ Message Input
     (First launch)     ↑               ↓
                        └───────────────┘

Screen Layout:

┌──────────────────────────┐
│ ● BitChat      2 peers   │ ← Status Header
├──────────────────────────┤
│ sender1: Hello there     │
│ > You: Hi! How are you?  │ ← Message List
│ sender2: Great!          │   (Scrollable)
│          ↕               │
├──────────────────────────┤
│  OK=Send Back=Menu       │ ← Help Footer
└──────────────────────────┘

Limitations

Due to Flipper Zero hardware constraints:

• Limited message history (~50 messages)
• No Nostr support (internet-based features)
• No location channels
• Text-only (no media)
• Simplified UI optimized for small display

Development Status

✅ Completed:

• Binary protocol encoder/decoder
• Identity management and storage
• BLE transport layer structure
• Complete UI/UX implementation
• Chat view with scrolling
• Text input for messages
• Nickname setup flow
• Status indicators and feedback

🚧 In Progress:

• Noise Protocol encryption
• Actual BLE advertising/scanning
• Message relay implementation
• Peer discovery

License

Public domain (Unlicense) - same as BitChat