Todo Backend

A production-ready REST API for a task management application with Pomodoro timer integration. Built with Spring Boot and deployed on a Linux VM.

Live Demo: phasetheday.me

Tech Stack

Category	Technology
Language	Java 21
Framework	Spring Boot 3.5.4
Security	Spring Security, JWT
Database	PostgreSQL
ORM	Spring Data JPA (Hibernate)
Build	Gradle
Deployment	Linux VM, Systemd, Nginx

Architecture

┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│   React     │────▶│ Spring Boot │────▶│ PostgreSQL  │
│  Frontend   │     │   REST API  │     │  Database   │
└─────────────┘     └─────────────┘     └─────────────┘
                           │
                    ┌──────┴──────┐
                    │ JWT Auth    │
                    │ Filter      │
                    └─────────────┘

Key Features

Secure Authentication

• Stateless JWT-based authentication
• Password encryption with BCrypt
• Token validation filter chain

RESTful API Design

• Clean resource-based URL structure
• Proper HTTP methods and status codes
• Request/Response DTOs for data transfer

Pomodoro Integration

• Track focus sessions per task
• Aggregate duration statistics
• Productivity metrics support

API Endpoints

Method	Endpoint	Description
POST	/api/v1/auth/signup	Register new user
POST	/api/v1/auth/login	Authenticate and get JWT
GET	/api/v1/todos	Get all todos
POST	/api/v1/todos	Create todo
GET	/api/v1/todos/{id}	Get specific todo
PATCH	/api/v1/todos/{id}	Update todo
DELETE	/api/v1/todos/{id}	Delete todo
POST	/api/v1/todos/{id}/pomodoros	Log pomodoro session

Technical Highlights

Security Implementation

• Custom JwtAuthenticationFilter for token validation
• Configured CORS for frontend integration
• Stateless session management

Database Design

• JPA entity relationships (User → Todo → Pomodoro)
• Optimized queries with Spring Data JPA
• Environment-specific configurations (local/prod)

Deployment Pipeline

• Systemd service management
• Environment variables for sensitive data
• Nginx reverse proxy configuration

Local Development

# Prerequisites: Java 21, PostgreSQL

# Set environment variables
export DB_PASSWORD=your_password
export JWT_SECRET=your_secret

# Run the application
./gradlew bootRun

Project Structure

src/main/java/com/moon/todo/
├── config/          # Security, CORS configuration
├── controller/      # REST API endpoints
├── dto/             # Request/Response objects
├── entity/          # JPA entities
├── repository/      # Data access layer
├── security/        # JWT filter, auth components
└── service/         # Business logic

What I Learned

• Implementing JWT authentication from scratch with Spring Security
• Managing environment-specific configurations for local and production
• Deploying Spring Boot applications on Linux with systemd
• Database migration from MariaDB to PostgreSQL
• CORS configuration for frontend-backend communication