Alpha-Pay: Distributed Digital Wallet System

Alpha-Pay is a production-ready, microservices-based digital wallet application. Built with Spring Boot 3.x and Java 21, it features a fully dockerized environment, secure JWT authentication, and a robust CI/CD pipeline.

System Architecture

The application is architected as a set of decoupled microservices that communicate over a virtualized Docker network:

• API Gateway (8080): Central entry point using Spring Cloud Gateway. Handles JWT validation and request routing.
• User Service (8081): Manages user lifecycle, authentication, and secure profile storage.
• Wallet Service (8083): Core ledger service that manages user balances.
• Transaction Service (8082): Auditing service that tracks every credit/debit event across the system.

Tech Stack & Tools

• Language: Java 21 (LTS)
• Framework: Spring Boot 3.x, Spring Cloud Gateway, Spring Data JPA
• Security: Spring Security, JSON Web Token (JWT)
• Database: PostgreSQL (Cloud-hosted via Neon DB)
• Containerization: Docker & Docker Compose
• CI/CD: GitHub Actions (Automated build & test pipelines)

Local Setup Instructions

1. Prerequisites

• Install Docker Desktop
• Install Git

2. Configuration

Create a .env file in the root directory:

DB_URL=jdbc:postgresql://your-neon-db-instance-url
DB_USERNAME=your_db_username
DB_PASSWORD=your_db_password

3. Launching the System

Run the following command to build and start all services:

docker-compose up --build

The services will be accessible at localhost:8080 via the Gateway.

API Endpoints & Testing Flow

Step 1: User Registration

POST http://localhost:8080/alphapay/user/register

Payload:

{
  "fullName": "John",
  "email": "john@test.com",
  "password": "securePassword123"
}

Step 2: Login (Get JWT Token)

POST http://localhost:8080/alphapay/user/login

(Copy the generated token for subsequent requests)

Step 3: Add Money to Wallet

POST http://localhost:8080/alphapay/wallet/{userId}/add-money?amount=500

Headers:

Authorization: Bearer <your_jwt_token>

🔄 CI/CD Workflow

This repository is integrated with GitHub Actions. The pipeline automatically builds all 4 microservices individually on every push to the beta and alpha branches to ensure build stability.

🚧 Roadmap

• Rate Limiting: Implement request throttling at the Gateway level.
• Saga Pattern: Distributed transaction management for data consistency.
• Service Discovery: Integration with Netflix Eureka.

---

Developed by Abhishek Gour

Solving digital payment complexities one microservice at a time.