📘 README.md — Content Calendar API (Spring Boot 3)

🚀 Project Summary

The Content Calendar API is a full Spring Boot 3 backend application built as part of my advanced learning path. This project demonstrates how to build, structure, deploy, and operate a real-world Spring Boot service — from local development with H2 to a fully deployed PostgreSQL-backed service on Railway.

I built this project to:

• Refresh and deepen my Spring Boot knowledge (especially SB3 changes)
• Strengthen my Java backend portfolio for job applications
• Learn modern deployment workflows (Docker → Railway)
• Understand environment configurations (dev vs prod)
• Build a real API that is accessible online

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🧩 Why This Project Exists

Backend engineering involves much more than writing endpoints. This project shows full-stack backend competency:

• Building REST APIs the Spring way
• Managing two databases (H2 for dev, PostgreSQL for prod)
• Working with Docker containers
• Using profiles for environment-specific behavior
• Deploying production-ready apps using Railway
• Handling sensitive configuration with environment variables
• Debugging DB schema & connection issues in real deployment environments

It demonstrates the skills companies expect from a Junior → Mid Java Backend Developer.

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🧠 What Problem This Project Solves

This project is a teaching and demonstration tool. It solves the questions every beginner backend engineer faces:

• How do I build a Spring Boot 3 REST API?
• How do I work with PostgreSQL and H2?
• How do I configure Docker + containers?
• How do I switch between dev and prod environments?
• How do I deploy a Java backend to Railway?
• How do I manage environment variables safely?
• How do I structure a real backend application cleanly?

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🔥 Tech Stack

Layer	Technology
Language	Java 17
Framework	Spring Boot 3
Web	Spring MVC
Persistence	Spring Data JPA
Local DB	H2 (in-memory)
Production DB	PostgreSQL
Deployment	Railway
Container	Docker / Docker Compose
Monitoring	Spring Boot Actuator
Build Tool	Maven
Version Control	GitHub

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🏗️ Architecture Overview

                ┌──────────────────────────────┐
                │         Frontend (optional)   │
                │  React / Next.js / Vue        │
                └───────────────┬──────────────┘
                                │ HTTP/JSON
                                ▼
                    ┌────────────────────────┐
                    │    Spring Boot API     │
                    │  Controllers (MVC)     │
                    ├────────────────────────┤
                    │   Service Layer        │
                    │  Business Logic        │
                    ├────────────────────────┤
                    │ Repository Layer (JPA) │
                    └──────────────┬─────────┘
                                   │
                        ┌──────────┴───────────┐
                        │                       │
                 ┌──────────────┐      ┌────────────────┐
                 │  H2 (Dev)    │      │ PostgreSQL Prod │
                 └──────────────┘      └────────────────┘

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🧪 Screenshots

📌 Railway Deployment Screenshot

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🐳 Docker Container Screenshot

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📡 API Response Screenshot (Postman / Thunder Client)

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⚙️ Quick Start (TL;DR)

🖥️ Local Development (H2)

This uses the development profile and H2 in-memory DB.

git clone <YOUR_GITHUB_REPO_LINK>
cd content-calendar
./mvnw spring-boot:run

Access H2 console (dev only):

http://localhost:8080/h2-console

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🐳 Local with Docker + PostgreSQL

docker compose up -d
SPRING_PROFILES_ACTIVE=prod ./mvnw spring-boot:run

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☁️ Production Deployment (Railway)

Steps:

1. Push code to GitHub

2. Connect Railway → New Service → Deploy from Repo

3. Add environment variables:

   • SPRING_DATASOURCE_URL
   • SPRING_DATASOURCE_USERNAME
   • SPRING_DATASOURCE_PASSWORD

4. Deploy Docker image

5. Railway auto-creates PostgreSQL DB

6. Run health checks via Actuator

7. The API becomes public

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📚 API Examples

POST — Create Content

POST /api/content
Content-Type: application/json

{
  "title": "First Content",
  "description": "Learning Spring Boot",
  "status": "IDEA",
  "contentType": "VIDEO"
}

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GET — Get All Content

GET /api/content

Example Response

[
  {
    "id": 1,
    "title": "First Content",
    "description": "Learning Spring Boot",
    "status": "PUBLISHED",
    "contentType": "ARTICLE"
  }
]

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🛠️ Technical Decisions

✔ H2 for Development

• Instant startup
• No external dependencies
• Perfect for fast testing

✔ PostgreSQL for Production

• Durable / reliable

• Cloud compatible

• Supports real-world scaling needs

✔ Environment Profiles

• dev → H2, debug logs
• prod → PostgreSQL, env variables, no dev tools

✔ Docker & Compose

• Standardized environment
• Same config everywhere
• Railway supports Docker natively

✔ Actuator

• Health checks
• Metrics
• Info endpoints

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🧩 Challenges & How I Solved Them

🧱 1. Docker Deployment

Railway requires correct env variable mapping + working Dockerfile. Solved via standardized Dockerfile + Railway environment config.

🔑 2. Sensitive Data Management

Learned to avoid hardcoded DB credentials. Used environment variables everywhere.

🔄 3. Switching Between H2 and PostgreSQL

Implemented profile-based config:

• application-dev.yml
• application-prod.yml

🗄️ 4. Initial Schema & Sample Data

Railway calls schema at startup — needed to ensure proper migrations per profile.

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🧠 What I Learned

• Spring Boot 3 fundamentals (MVC, JPA, Actuator)
• Dependency Injection, IoC, Spring Context
• REST API structure & layering
• PostgreSQL & H2 configuration
• Docker images, containers, Compose
• Railway deployment pipeline
• Working with profiles & env variables
• Diagnosing real production failures

This project made me more confident as a backend developer.

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👤 Author

Jo — Java Backend Developer Building production-ready backend services with Spring Boot.

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