Portfolio Experience Capabilities Contact
Backend Java Developer

Hoang
Kim Tin

Backend Java Developer with 2+ years of experience building and owning microservices in a production cloud platform. Specialized in VM/LXC provisioning integrated with Proxmox & VMware, concurrency handling, and async workflows.

Java

Work
Experience

Mar 2024 – Present

Long Van System Solution

Backend Java Developer · Spring Boot, MongoDB, Redis, GitLab

Current Role

Cloud Computing Module — Sole Developer (Apr 2025 – Present)

  • Architected and owned end-to-end VM/LXC provisioning system integrated with Proxmox & VMware APIs, supporting full lifecycle operations (create, resize, delete).
  • Designed layered architecture: Computing Service → SDK abstraction → Hypervisor Service → Infrastructure, decoupling business logic from hypervisor specifics.
  • Built Computing Pool of pre-provisioned resources, reducing VM provisioning time by ~60% for pool-allocated deployments vs. cold-start.
  • Built async deployment pipeline using Redis-backed queue for IP allocation and background jobs, enabling concurrent provisioning without race conditions.
  • Identified and resolved duplicate IP allocation bug caused by concurrent queue consumers — applied distributed locking, eliminated IP conflicts in production.
  • Implemented resource reconciliation mechanism that periodically compares service state against live infrastructure, detects mismatches, and prevents resource leakage.

Service Management Module — Key Developer (Jun 2024 – Apr 2025)

  • Developed and maintained full service lifecycle: provisioning, renewal, resource scaling, and state management across multi-step deployment workflows.
  • Built REST APIs for user portal covering service creation, modification, and status tracking.
  • Modeled MongoDB schema for service entities, supporting complex lifecycle states (deploying, deployed, failed, expired) with efficient query patterns.

E-Commerce Integration (Mar 2024 – Jun 2024)

  • Integrated order fulfillment APIs and real-time webhook handlers for Shopee, Lazada, and TikTok Shop.
  • Automated order processing pipeline across three major Vietnamese e-commerce platforms.

Key Projects & Impact

VM/LXC Provisioning System

End-to-end machine provisioning integrated with Proxmox & VMware via a clean layered architecture decoupling business logic from hypervisor specifics.

Impact: ~60% reduction in VM provisioning time with pool-allocated deployments.
Async Deployment Pipeline

Redis-backed queue handling IP allocation and concurrent deployments with distributed locking to prevent race conditions.

Impact: Eliminated duplicate IP allocation bugs entirely in production.
E-Commerce Webhook Integration

Real-time webhook handlers for Shopee, Lazada, and TikTok Shop — fully automated order fulfillment pipeline.

Impact: Unified 3 major Vietnamese e-commerce platforms into a single system.

Technical
Capabilities

Languages & Frameworks

Java 11Spring Boot 2.7Spring Data MongoDBJSFPrimeFacesJavaScript

Databases & Caching

MongoDBMySQLRedis

Architecture & Integration

MicroservicesRESTful APIEvent-drivenProxmox APIVMware APIShopee / Lazada / TikTok APIs

Concepts

Async ProcessingConcurrencyDistributed LockingNoSQL ModelingSOLID

Testing & DevOps

JUnitMockitoGitGitLabdraw.io

Education

Software EngineeringGia Dinh UniversityGPA 3.42 / 4.0DistinctionTOEIC 550