Architecture

Booking Calendar is designed with a focus on simplicity, performance, and ease of self-hosting.

Unified Process

In production, the application runs as a single process. The Bun server serves both the REST API and the Frontend Static Assets.

• API Prefix: /api/
• Frontend Dir: src/client/dist

Directory Structure

├── src
│   ├── client          # React frontend (Vite)
│   ├── server          # Bun backend
│   │   ├── controllers # Request handlers
│   │   ├── services    # Business logic
│   │   ├── repositories # Data access
│   │   ├── entities    # TypeORM definitions
│   │   └── mail        # Handlebars templates
│   └── docs            # VitePress documentation
├── data                # SQLite database storage
└── docker-compose.yml  # Production deployment

Data Persistence

The system uses TypeORM with SQLite (via sqljs or native driver). This allows for file-based storage, making the database portable and easy to back up without complex database management systems.

Asynchronous Tasks

Notifications and heavy tasks are handled asynchronously. For example, email sending is non-blocking, ensuring that the user receives an immediate response after booking while the email is sent in the background.

Security Layers

1. JWT Auth: Token-based authentication for the admin panel.
2. Rate Limiting: Protects endpoints from brute-force and spam.
3. HMAC Signing: Ensures integrity and authenticity of webhooks.
4. CORS: Configured to restrict access as needed.