SyncCode

SyncCode is a production-ready, real-time collaborative coding workspace designed to enable developers to code together seamlessly with shared editor states, live cursor tracking, and secure, isolated execution of code in multiple programming languages.

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🚀 Key Features

• Real-time Collaborative Editing: Seamless code collaboration powered by Yjs CRDTs over WebSockets.
• Live User Presence: Track remote cursor positions, selection ranges, active typing states, and online users in real-time.
• Multi-language Sandbox Execution: Safely run Python, JavaScript, and C++ code. Executions are strictly isolated inside Docker containers with custom CPU/memory caps, disabled networking, and read-only filesystems.
• Production Security: Secured with JSON Web Tokens (JWT) for authentication, custom input sanitization, rate-limiting on endpoints, and Docker security isolation.
• Scalable Core Architecture: Utilizes Redis for horizontal scaling and adapter syncing across multiple WebSocket server instances.
• Full Observability: Integrated Prometheus metrics endpoints and Grafana dashboards for monitoring system status and container metrics.

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📁 Repository Structure

├── synccode_frontend/     # React + Vite frontend client
├── synccode_backend/      # Express + Socket.io collaboration server
├── synccode-executor/     # Sandboxed code execution service (Docker based)
├── monitoring/            # Prometheus config and Grafana provision files
├── nginx/                 # Nginx configurations for reverse-proxy routing
├── Docker-compose.yml     # Local orchestration stack
├── SyncCode-local.sh      # All-in-one setup bash script
└── architecture.md        # Technical architectural design document

For a detailed walkthrough of the system flow, database syncs, and sandbox architecture, read architecture.md.

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⚙️ Configuration & Environment Variables

All main services use environment variables. A template is provided in env.example.

Setup Environment

Create a .env file at the project root by copying the template:

cp env.example .env

The setup script SyncCode-local.sh automatically creates and populates the .env file with a cryptographically secure JWT_SECRET key if one doesn't exist.

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🛠️ Getting Started

📋 Prerequisites

Make sure you have the following installed on your machine:

• Node.js (v18+)
• npm
• Docker & Docker Compose

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Method A: Docker Compose Deployment (Recommended)

To run the complete production-grade stack (Frontend, Backend, Executor, Redis, Nginx, Prometheus, Grafana) automatically:

1. Run the local setup script:

   ./SyncCode-local.sh

   This pulls the required sandbox Docker images (node:24-alpine, python:3.11-alpine, gcc:13-alpine), installs Node dependencies, and creates runtime configs.

2. Start the services:

   ./start.sh

3. Access the applications:

   • Backend Server: http://localhost:3001
   • Code Executor: http://localhost:3002
   • Prometheus: http://localhost:9090
   • Grafana: http://localhost:3000 (Default credentials: admin / admin)
   • Nginx Proxy Gateway: http://localhost:80

4. Stop the services:

   ./stop.sh

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Method B: Native Setup (No Containers)

If you prefer to run services natively on your local environment:

1. Start Redis Server on your default port (6379).
2. Run the native start script:

   ./start-native.sh

   This launches the backend server and code executor as background processes and logs stdout to ./logs/.
3. Stop native processes:

   ./stop-native.sh

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🧪 Testing and Verification

To verify that the backend and executor services are operational:

# Check Backend Health Status
curl http://localhost:3001/health

# Check Code Executor Health Status
curl http://localhost:3002/health

Both endpoints should return status "healthy" along with runtime statistics.