Jannis Braun
0d74d1d112
HEALTH_CHECK_INTERVAL_MS was 1 h, but ROTATION_GRACE_PERIOD_MS is 15 min.
Phase skew between two peers' health-check ticks could stretch rotation
finalization desync up to ~1 h, during which signatures from the already-
finalized side verify against the other side's primary-only secret (grace
has expired; verifyPeerSignature stops trying the pending secret). With
AUTH_FAILURE_THRESHOLD = 5 and the existing backoff schedule, this
occasionally tripped legitimate rotations into needs_attention.
Setting the interval to 15 min (= ROTATION_GRACE_PERIOD_MS) guarantees a
finalization tick fires within one grace window on each side, so the
cross-verification window where one peer signs with NEW while the other
still treats NEW as pending cannot outlast the grace period.
Per-tick cost is negligible for the worker's steady state: the only
network fetches are per-active-peer /peer/rotate calls when the 90-day
rotation interval hits (rare) and per-unreachable-peer /instance/info
health pings (bounded by outage count). Going lower than 15 min would
reduce the residual desync but increase tick overhead with diminishing
returns; 15 min is the grace-period-aligned value that the original spec
("runs hourly") deviated from without justification.
Follow-up #20 from S2S DM unification backlog; reduces #19 false-positive
rate (outbox auth-failure transition) on legitimate rotations.
Backspace
Open-source, self-hosted Discord alternative built with TypeScript.
Features
- Real-time text messaging with WebSocket
- Servers, channels, and role-based permission management
- Voice and video chat via LiveKit
- Screen sharing with configurable quality (VP9)
- Direct messages (1-on-1 and group DMs up to 10)
- DM voice/video calls with ringing
- Friend system with requests
- File uploads and image sharing
- Markdown message formatting with syntax highlighting
- Message reactions, replies, and editing
- Typing indicators, presence status, and read states
- Invite system with shareable codes
- Instance-level admin panel (streaming limits)
- Desktop app (Electron)
- Mobile-responsive web UI
- Docker deployment
Tech Stack
| Layer | Technology |
|---|---|
| Backend | Fastify + TypeScript |
| Database | SQLite (better-sqlite3) + Drizzle ORM |
| Auth | JWT + bcrypt |
| Real-time | WebSocket (ws) |
| Frontend | React 18 + Tailwind CSS + Zustand |
| Voice/Video | LiveKit |
| Desktop | Electron |
| Build | Vite + pnpm workspaces |
Quick Start with Docker
# Clone the repository
git clone https://github.com/your-username/backspace.git
cd backspace
# Create environment file
cp .env.example .env
# Generate a JWT secret
echo "JWT_SECRET=$(openssl rand -hex 32)" >> .env
# Start Backspace
docker compose up -d
Open http://localhost:3000 in your browser. A default server "Backspace" is created automatically.
Default admin account: admin / admin123 (change this after first login).
Development Setup
Prerequisites
- Node.js 20+
- pnpm 8+
Install
pnpm install
Configure
cp .env.example .env
# Edit .env with your settings (generate a JWT_SECRET)
Run
# Start both server and web dev server
pnpm dev
# Or start individually
pnpm dev:server # API server on :3005
pnpm dev:web # Vite dev server on :5173
Build
pnpm build
This builds the shared types, server, and web frontend. The server serves the built frontend in production mode.
Project Structure
Backspace/
├── packages/
│ ├── shared/ # Shared TypeScript types & permissions
│ ├── server/ # Fastify API + WebSocket server
│ ├── web/ # React frontend (Vite + Tailwind)
│ └── desktop/ # Electron desktop app
├── data/ # SQLite DB + uploads (created at runtime)
├── Dockerfile
├── docker-compose.yml
└── .env.example
Voice & Video
Voice and video requires a LiveKit server. Set these in your .env:
LIVEKIT_URL=wss://your-livekit-server
LIVEKIT_API_KEY=your-api-key
LIVEKIT_API_SECRET=your-api-secret
Without LiveKit configured, text chat works fully but voice/video channels will not connect.
API
The server exposes a REST API and WebSocket endpoint:
- REST API:
http://localhost:3000/api/* - WebSocket:
ws://localhost:3000/ws - Health check:
GET /api/health
See CLAUDE.md for the full API reference.
Desktop App
The Electron desktop app wraps the web UI and adds system tray, notifications, and native window controls.
cd packages/desktop
pnpm build:ts # Compile TypeScript
pnpm dev # Run in development
pnpm build # Package for distribution
License
MIT