MiniBank Backend API

MiniBank is a Spring Boot REST API that simulates core digital banking operations: secure user authentication, account management, money transfers, transaction history, fraud flagging, and admin oversight.

Features

• JWT-based authentication with Spring Security
• Role-based access control (CUSTOMER, ADMIN)
• Account creation and balance tracking
• Account statuses: ACTIVE, FROZEN, CLOSED
• Internal transfers with transactional consistency (@Transactional)
• Transaction history filtering (date, amount, type) with pagination/sorting
• Fraud/risk flagging for suspicious transfers (high-value/frequent activity)
• Admin APIs for dashboard metrics, account freezing, and flagged transaction review
• Audit logging for sensitive admin actions

Tech Stack

• Java 17
• Spring Boot 4
• Spring Web MVC
• Spring Data JPA
• Spring Security
• JWT (jjwt)
• MySQL 8
• Liquibase (migrations + seed data)
• OpenAPI/Swagger (springdoc)
• JUnit 5 + Mockito
• Docker Compose (local MySQL)
• dotenv support for local environment secrets

Data Model

• users
• roles
• user_roles
• accounts
• transactions
• fraud_flags
• audit_logs

API Documentation

• Swagger UI: http://localhost:8080/swagger-ui.html
• OpenAPI JSON: http://localhost:8080/api-docs

Notes

• Configuration is environment-driven for sensitive values (JWT/admin secrets)
• Built as a practical backend foundation for digital banking workflows and future production-style enhancements