Hi, I'm Jeffy Fung
Full-stack engineer with a behavior-driven, systematic mindset rooted in statistics and AI. I build robust web and mobile applications — from React/Next.js interfaces to scalable back-end systems — and incorporate AI solutions to explore innovative possibilities.
Who I Am
About Me
A bit more about my background, professional story, and what drives me as an engineer.
Fung Ming Chung
Jeffy Fung
Software Engineer
Status
Available to explore new possibilities
Location
Hong Kong
Focus
Full-Stack Engineering
Languages
English · 中文
My Story
I'm Jeffy Fung, a full-stack engineer with 4+ years shipping web and mobile applications — Rails/Next.js portals serving 20k+ users, a React Native app launched in 2 months, and back-end systems covering payments, scheduling, and notifications.
I also incorporate AI into my work: building RAG chatbots, automation pipelines, and AI tooling. I approach software with a behavior-driven, systematic mindset — designing for scale and thinking through the full product lifecycle.
Outside of work, I enjoy sharing what I've learned by writing technical articles. I'm currently open to new roles where I can tackle challenging problems and keep growing as an engineer.
Career Interests
What I Know
Skills & Technologies
Technologies and tools I use to build modern, scalable applications.
Languages
Frontend
Backend
Tools & Practices
Math & Statistics
My Journey
Work Experience
4+ years building full-stack web and mobile applications across EdTech, sports retail, and academia.
Senior Software Engineer
PUMA
Full-time 1-year Contract
- Developing internal automation pipeline for PUMA global sourcing, carefully handling sensitive price list data for suppliers and the costing team.
- Assisting in developing an internal AI chatbot for handling post-order issues for related parties.
Senior Software Engineer
Preface
Full-time Promoted from Software Engineer
- Developed and maintained scalable Rails/Next.js web portals serving 20k+ users (admins, franchises, teachers, and customers) including QR code attendance, class/event scheduling across 10+ locations with conflict detection.
- Launched a cross-platform EdTech lifestyle mobile app (React Native) from 0 to 1 in 2 months, deployed to iOS and Android app stores.
- Designed scalable systems to support the full customer journey: payment, notification, voucher, and course/notes viewing systems.
- Built a RAG chatbot POC using Python/Ollama, self-hosted on GCP, demonstrating AI capabilities for admin operation automation.
Research Assistant
Hong Kong Polytechnic University
Part-time
- Performed causal inference analysis using Mendelian Randomization in R, identifying key factors affecting disease pathways.
- Led statistical analysis for maternal health studies on sustaining exclusive breastfeeding using linear regression (ANOVA).
- Created reproducible R pipelines for processing clinical datasets.
- Developed the Hong Kong Growth Study website.
Student Intern
Hong Kong Observatory
Full-time One Year Placement
- Researched and developed an SVM-based rainfall intensity prediction model (Python, scikit-learn) using EFI/SoT indices.
- Discovered imaginary regions for EFI/SoT through Calculus, contributing to the mathematical foundation of the model.
- Visualised results with decision boundary diagrams in Python; successfully integrated findings into the weather forecasting system.
Senior Software Engineer
PUMA
Full-time 1-year Contract
- Developing internal automation pipeline for PUMA global sourcing, carefully handling sensitive price list data for suppliers and the costing team.
- Assisting in developing an internal AI chatbot for handling post-order issues for related parties.
My Work
Featured Projects
A selection of projects I've built — each solving real-world problems.
AI RAG Chatbot
An agentic RAG chatbot that summarises news articles. Built with Python and Ollama, self-hosted on GCP, demonstrating retrieval-augmented generation for automated information processing.
Object Detection Playground
A side project for exploring real-time object detection using the YOLO model family. Experiments with model configurations, inference speed, and visualising detection results.
Chatbot Load Test
A simplified infrastructure load test simulating 1,000 concurrent active users on a chatbot system. Analyses throughput, latency, and bottlenecks under pressure.
Writing
Blog
I write about software engineering, TypeScript, React, Node.js, and lessons learned along the way. All posts are published on Medium.
Read my articles on Medium
Visit my Medium profile to browse all my posts on full-stack development, architecture, and engineering best practices.
Let's Connect
Get In Touch
Always open to exploring new possibilities — feel free to reach out and I'll get back to you promptly.
Whether you have a job opportunity, a project idea, or just want to say hi — my inbox is always open.