Transaction Service API

Secure RESTful backend for personal finance tracking
User authentication (JWT), transaction CRUD (income/expense/transfer), PostgreSQL + Flyway, clean architecture

Live Demo: https://transaction-service-29ts.onrender.com
Swagger UI (local): http://localhost:8080/swagger-ui.html

✨ Features

• JWT Authentication — secure registration, login, role-based claims
• Transaction Management — create, list income/expense/transfer entries
• Input Validation — DTOs + Jakarta Bean Validation + clean error responses
• Database — Flyway migrations, PostgreSQL (production), H2 (dev/tests)
• Clean Architecture — layered structure (controllers → services → repositories)
• Testing — unit tests (Mockito), context loading with Flyway integration
• Deployment Ready — Render-friendly with environment variables

🛠️ Tech Stack

Category	Technology
Language	Java 17
Framework	Spring Boot 3
Security	Spring Security + JWT
Persistence	Spring Data JPA + Hibernate
Database	PostgreSQL (prod) / H2 (dev/test)
Migrations	Flyway
Validation	Jakarta Bean Validation
Testing	JUnit 5 + Mockito
Deployment	Render
Documentation	Springdoc OpenAPI / Swagger UI

🚀 Quick Start (Local)

1. Clone the repository

   git clone https://github.com/LauraBaillie/transaction-service.git
   cd transaction-service
   

2. Set environment variables (or create .env file)

  export DB_URL=jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=FALSE
  export DB_USERNAME=sa
  export DB_PASSWORD=""
  export JWT_SECRET=super-secret-local-test-key-do-not-use-in-production-abcdefghijklmnopqrstuvwxyz123456
  export JWT_EXPIRATION=86400000   # 24 hours in ms

3. Build & run

  mvn clean spring-boot:run
  Test endpoints (Postman / curl)
  POST /api/auth/register → { "username": "testuser", "password": "test123" }
  POST /api/auth/login → get JWT token
  POST /api/transactions (with Authorization: Bearer <token>) → create transaction
  GET /api/transactions → list user's transactions

🧪 Testing All tests pass with clean separation: Bashmvn clean test

• Unit tests — service layer (Mockito)
• Integration-style — context loading + Flyway migrations in H2
• Coverage — focused on business logic & security mocking

🌐 Deployment (Render)

1. Connect GitHub repo to Render
2. Build command: mvn clean package
3. Start command: java -jar target/transaction-service-*.jar
4. Set environment variables in Render dashboard:
   • DB_URL, DB_USERNAME, DB_PASSWORD (use Render PostgreSQL add-on)
   • JWT_SECRET, JWT_EXPIRATION