Yew Jung Sien

Yew Jung Sien email: yewjung@gmail.com	Version	v0.1.5
Updated	2025-07-26

Summary

Backend engineer with 5+ years of experience building scalable systems in fintech. Skilled in leading architecture, improving performance, and delivering product features end-to-end.

Fun Stuffs

Multiplayer Poker

Built a real-time multiplayer Texas Hold ’Em game using Rust
Developed the terminal-based client UI with Ratatui, providing an interactive and responsive TUI experience
Implemented game state synchronization, room and player management and concurrent gameplay using WebSocket
Used Redis and PostgreSQL for real-time game state and persistent storage

Deck API

Developed a RESTful API in Go to simulate a 52-card deck
Used Redis for fast, im-memory state storage and efficient deck management

Experience

Backend Engineer @ BigPay (2023 - Present)

Led the architecture and implementation of credit and debit card top-ups, enabling seamless funding of user wallets at scale
Designed and built a new in-person onboarding flow, significantly streamlining the signup process for face-to-face customer interactions
Led the development of a feature enabling users to make charity donations through the app, integrating with external partners to ensure secure, user-friendly transactions.
Redesigned a core transaction storage system, improving performance, reliability, and maintainability while reducing system complexity. Oversaw the migration of all historical transaction data with zero downtime.
Architected and delivered a budget tracking service that empowers users to set and monitor overall and category-specific spending limits. Integrated real-time push notifications to proactively alert users when budgets are exceeded.
Built a real-time monitoring and alerting infrastructure using Grafana and Prometheus to detect unusual user behaviours and potential malicious activities. This system ensures early intervention and platform security.
Integrated Singpass, Singapore’s digital identity service, into the signup flow for Singaporean users, ensuring seamless onboarding experience.
Stack: Rust, Java, Kotlin, Spring Boot, Redis, PostgreSQL, Kafka, Prometheus, Grafana

Senior Software Engineer @ Theta Service Partner (2023 - 2023)

Led and design and implementation of an internal backend framework to streamline workflows and improve engineering efficiency
Optimized loan system performance for financial clients achieving a 10x reduction in response time.
Mentored and onboarded new engineers, helping them ramp up quickly and contribute effectively to client projects.
Stack: Java, Spring Boot, Angular, Vue, SQL Server

Software Engineer @ Theta Service Partner (2019 - 2023)

Created internal tools, optimising team workflows and productivity
Provided support to UK-based client projects and managed server deployment for seamless system operations
Stack: Java, Spring Boot, Angular, Vue, SQL Server