Car Rental Microservices

Overview

I built this project to practice production-style backend architecture instead of a single monolith. The system handles core rental workflows and enforces role-based access for customer and admin operations. A major goal was proving I could move a local database setup into AWS RDS while keeping development setup simple for day-to-day work.

Highlights

• Split business capabilities into focused Spring Boot services with clear REST contracts.
• Implemented JWT authentication with Cognito-backed OAuth2 flows for secure access.
• Added role checks to protect admin-only actions such as fleet management and pricing updates.
• Containerized local development so services and dependencies spin up consistently.

Architecture

• API layer routes requests to service-specific handlers with validation at the boundary.
• Each service owns its persistence concerns and communicates through HTTP APIs.
• Auth flow uses Cognito-issued tokens that are verified in backend middleware.
• Application secrets and environment values are externalized for local and cloud parity.

Key Learnings

• Service boundaries are easier to maintain when contracts are defined early.
• Token lifecycle handling is a common source of bugs and needs explicit testing.
• Migration to managed databases is smoother when schema changes are automated.
• Dockerized workflows reduce setup friction and onboarding time.

Outcomes

• Services: 3 domain services plus auth integration
• Deployment target: AWS RDS-backed environment