Huy Đào Ngọc
Backend Software Engineer building scalable systems.
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Built a robust core booking module to handle complex, multi-step flight reservation workflows. The service ensures strict data integrity across multiple relational database tables using transactional boundaries.
Key responsibilities
Atomic transactions: Applied @Transactional to guarantee that parent booking records (BookingMaster), child entity details (BookingFlight), and payment states succeed or fail as a single unit, preventing orphaned data.
Data validation: Implemented rigorous pre-checks for crucial business inputs (flight numbers, PNR codes, routing, and pricing) before any database operations occur.
Clean code: Leveraged the Builder design pattern for clean, readable entity construction and maintained strict relational mapping between core operational tables.
Tech Stack: Java, Spring Boot, JPA/Hibernate, Relational Database.
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Developed a transactional and real-time bidding module for a distributed auction platform. The system ensures data consistency, enforces strict bidding business rules, and updates all active clients instantaneously.
Key logic and features:
Microservices integration: Implemented cross-service communication (auctionServiceClient) to securely fetch external auction states and trigger remote time-extension events.
Anti-Snipe algorithm: Engineered an automated validation mechanism that detects last-minute bids and dynamically extends auction deadlines to ensure fair competition.
Real-Time broadcasting: Integrated WebSocket (STOMP) protocols to push instant, live bid updates to all concurrent users viewing the auction room.
Data consistency: Utilized @Transactional boundaries to maintain strict database integrity and prevent race conditions during high-frequency bidding scenarios.
Tech Stack: Java, Spring Boot, WebSockets (STOMP), Microservices Architecture.
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Developed a dynamic backend module that automatically transforms standard two-sided flashcards into interactive, 4-option multiple-choice quizzes.
Key logic and features:
Dynamic question fipping: Implemented randomized logic to swap questions and answers (front/back of cards) on the fly, ensuring a unique test experience every time.
Smart distractor generation: Wrote algorithms to randomly fetch and filter incorrect answers, guaranteeing 4 unique options per question without duplications.
Data serialization: Seamlessly processed QuerySets and serialized complex Python dictionaries into optimized JSON format (DjangoJSONEncoder) for easy frontend rendering.
Tech Stack: Python, Django, JSON.
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Implemented a robust and secure checkout flow for a service-based platform. This module handles everything from validating user inputs and calculating dynamic discounts to generating secure payment URLs.
Key responsibilities and logic flow:
Data validation: Verified service existence and validated promotional/coupon codes against the database to prevent fraudulent checkouts.
Transaction safety: Engineered a "Temp order" mechanism to store pending transactions, ensuring the main database remains clean if the payment process is abandoned.
Payment integration: Successfully integrated third-party payment gateway APIs (VNPAY sandbox), handling cryptographic hashing (SHA512) and secure URL building for seamless redirection.
Tech Stack used: Node.js, Express.js, SQL Database, Cryptography.
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