Bằngg

Backend Developer with 2 years of experience building e-commerce and B2B platforms for Korean clients. Skilled in payment, order and third-party API integrations, using idempotency and the outbox pattern for reliable processing. Adapts quickly to new domains and tech stacks, and works closely with clients and teammates to deliver on schedule.

Software Engineer (Backend) at WALA-ICT (2025-10 – Present)

Backend developer in a Vietnam–Korea team building commerce platforms for Korean clients.

• Tech stack: Java, Spring Boot, Spring Security, Spring Data JPA, PostgreSQL, Redis, Flyway, WebSocket, AWS, Docker, GitLab CI/CD.

Backend Developer — Multilingual E-commerce Platform (MOMO Plus) at WALA-ICT (2026-04 – Present)

Online grocery platform for foreign residents in Korea, serving customer, vendor and admin apps in 9 languages. Owned the order domain from checkout to refund.

• Payment: Integrated the Toss Payments API for card and virtual-account payments and refunds, with idempotent payment confirmation, webhook handling and cancellation.
• Order: Implemented parent/child checkout and cancel/return/exchange flows, using an event-driven design to decouple modules.
• WMS: Integrated orders with the warehouse management system using the transactional outbox pattern and idempotency keys for reliable, duplicate-free order sync.
• Address verification: Moved address-photo OCR to an async after-commit listener with confidence scores and Kakao postal-code lookup.

Backend Developer — B2B Dropshipping Platform (Domerang) at WALA-ICT (2025-10 – 2026-07)

Sellers list supplier products on major Korean marketplaces (Naver, Coupang, Gmarket) without holding stock, and suppliers ship directly to end customers.

• Authentication: JWT login, SMS/email account recovery, Redis-backed OTP with throttling, and AOP-based role checks.
• Multi-tenant accounts: business-scoped users, departments and permissions, with registrations verified via the Korean National Tax Service API.
• Notification system: after-commit events feed a Redis queue; a batch worker sends in-app, email, SMS messages, with per-user settings.
• CS conversations: 1:1 support inquiries, real-time bulk-purchase chat over WebSocket/STOMP, and marketplace inquiry sync.
• Infrastructure & DevOps: Set up GitLab CI/CD and Docker Compose environments.
• Infrastructure & DevOps: Provisioned AWS EC2, RDS and S3 for hosting, database and file storage.
• Infrastructure & DevOps: Built monitoring with Prometheus, Loki and Grafana on Actuator metrics and structured logs.

Software Engineer (Backend) at Cosmodern (2024-11 – 2025-10)

In-house e-commerce marketplace connecting Vietnamese local fashion brands with shoppers, built and run by the company as its own production product.

• Tech stack: PHP, Laravel, Java, Spring Boot, MySQL, HTML/CSS, jQuery, Docker, GitLab.
• Maintained a legacy full-stack Laravel e-commerce system (server-rendered Blade views), shipping features and production fixes.
• Contributed to a new Java REST API layer the team built to support a mobile app, replacing page-bound request handling with reusable endpoints.
• Integrated the OnePay payment gateway and GHTK shipping API (fee calculation, shipment creation and order tracking) into the checkout flow.
• Integrated Slack notifications for new orders and payments, and rebuilt brand filtering with sorting and visibility rules.

Bachelor of Engineering in Information Technology – Nong Lam University – Ho Chi Minh City (2021-09 – 2025-11)