Java Backend Developer

Lê Phát Khôi Nguyên

Software Developer

**.***.**2.09 **********.******@*****.*** https://github.com/overcode250204 Ho Chi Minh EXPERIENCE

FPT Software Sep 2025 - Dec 2025

Java Developer

Team size: 11 Role: Back-end Developer

Project: Laboratory Management System (LMS)

An enterprise-grade software solution designed to digitize, automate, and integrate laboratory operations within clinical environments. It manages the complete lifecycle of laboratory workflows — from patient registration, test ordering, and instrument integration to result validation and reporting.

Key Responsibilities:

• Participated in designing and implementing IAM Service, Patient Service, and Test Order Service APIs under the guidance of senior developers.

• Contributed to configuring Spring Cloud Config Server, API Gateway, and Eureka Discovery Server for the microservices architecture.

• Assisted in developing a custom API Gateway using Spring Cloud Gateway, supporting authentication, rate limiting, and centralized routing.

• Implemented Inbox-Outbox Pattern with Kafka to help ensure event consistency in inter-service communication.

• Gained hands-on experience with AWS services (Cognito, Lambda, S3, CloudWatch, DynamoDB) in a real production-grade environment.

• Collaborated with a team of 11 members, participating in code reviews and resolving integration issues. PROJECTS

BizLedger — Polyglot Microservices Platform July 2026 - August 2026 Team size: 1 (Personal project) Role: Full-stack Developer A self-initiated, enterprise-style multi-tenant SaaS platform for business/inventory management (catalog, inventory, orderto-cash, payments), built as 9 independently deployable microservices across Java and C# to practice production distributed-systems patterns end-to-end, from architecture to observability.

Key Responsibilities:

• Designed and built 7 Java Spring Boot microservices (Identity, Catalog, Inventory, Order, Payment, Audit, API Gateway) plus a C# .NET Notification service, each owning its own PostgreSQL database (database-per-service).

• Implemented the Saga Orchestrator pattern in the Order Service to coordinate order approval across Inventory and Payment services with compensating transactions on failure, avoiding distributed-lock 2-phase commit.

• Implemented multi-tenant Identity Service: JWT with rotating refresh tokens, RBAC (roles/permissions), API key management, and SSO/MFA endpoints; centralized JWT verification at the API Gateway (Spring Cloud Gateway), which forwards trusted identity headers downstream.

• Added Spring Cloud Config Server and Eureka Service Registry for centralized configuration and service discovery.

• Integrated Elasticsearch for full-text product search and centralized audit-log search/analytics via a dual-write strategy from PostgreSQL.

• Set up an observability stack: distributed tracing (Zipkin/Micrometer), Prometheus + Grafana dashboards, structured JSON logging, and Redis-based rate limiting at the gateway.

• Built the C# Notification Service with SignalR for real-time push, a Kafka inbox consumer, and a webhook subscription/delivery system.

• Built the frontend (React 18, TypeScript, Tailwind CSS) covering Identity/RBAC, Catalog, Inventory, Orders, Billing, Audit, Compliance, Security and Realtime modules.

• Containerized the full stack with Docker Compose (Postgres, Kafka, Redis, Elasticsearch, Kibana, Prometheus, Grafana, Zipkin) and set up a GitHub Actions CI pipeline building every service in parallel. Tech Stack: Java 21, Spring Boot, Spring Cloud (Gateway, Config, Eureka), Spring Security, Apache Kafka, PostgreSQL, Flyway, Redis, Elasticsearch, C# / .NET, SignalR, React, TypeScript, Tailwind CSS, Docker Compose, GitHub Actions, Prometheus, Grafana, Zipkin. Github:

• https://github.com/overcode250204/bizledger

• https://github.com/overcode250204/bizledger-ui

SKILLS

Java Java Core, OOP, Collections, Exception Handling, Java 21, Servlet, JSP Spring Boot Spring MVC, Spring Data JPA, Hibernate, Spring Security, RESTful API Microservices Spring Cloud, API Gateway, Eureka, Config Server C# & .NET ASP.NET Core, EF Core, LINQ, Razor Pages, Blazor Pages, SignalR Database & SQL PostgreSQL, SQL Server, MongoDB, SQL, Database design, Flyway Messaging & Distributed Systems Apache Kafka, event-driven architecture, Inbox-Outbox, Asynchronous processing Frontend Development JavaScript, HTML, CSS, ReactTS, Material UI, AJAX, jQuery Cloud & AWS AWS Cognito, IAM, Lambda, S3, CloudWatch, DynamoDB, EC2, ECR DevOps & Deployment Docker, Jenkins, GitHub Actions, Nginx, CI/CD Testing JUnit, TestNG, TDD, DDT, Selenium

Observability Prometheus, Grafana, Zipkin

Operating Systems Linux (Arch Linux), Windows

Version Control Git, GitHub, GitLab

AI-assisted development Claude, Gemini, ChatGPT, Prompting for workflow optimization Soft Skills Teamwork, Communication, Self-learning, Adaptability, Time management Languages English, Vietnamese, Japanese

EDUCATION

FPT University October 2022 - July 2026

Bachelor of Information Technology - BIT, Software Engineering CyberSoft Coding Academy March 2024 - October 2024 Comprehensive Java & Spring Boot Backend Development Course

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