Customer's problem, find it,
AI, build with it, fast,
Metrics, prove it.
Across 15 projects over 8 years, one thing became clear: an engineer is on the hook for the outcome, not the code.
Now I build fast with AI, heading toward the role that owns the entire product lifecycle.
Full case studies · portfolio.donggu.site
Sole architect and engineer of the VOC AI Dashboard, manual review replaced by 1,000+/day auto-classification across 4 integrated channels.
Tools I actually use on shipping projects.
Claude Code
Tmux
Cursor
CodexClaude Skills
n8n AI
Ollama
LangChain
Elasticsearch
pgvector
Next.js
Nuxt
React
Tailwind CSS
TypeScript
Vue.js
Flask
Java
Python
Spring Boot
FastAPI
Node.js
Flutter
Swift
PostgreSQL
Supabase
Firebase
MongoDB
MySQL
Oracle
AWS
Docker
GCP
Kubernetes
Terraform
NCP
Git
ArgoCD
GitLab
JenkinsN8N
Railway
Slack
Trello
Jira
Notion
Obsidian
ConfluenceClaude Design
Figma✏️PencilClaude Code💖Lovable🪡StitchPlatform launch • workflow builder • AX training, self-service operations, fully realized.
MVP shipped in 2 months (solo full-stack). Validated: 4.6 on Google Play, 1,000+ downloads.
"You shouldn't have to know how to talk to an AI." The moment a user feels they're writing a prompt, the product has failed.
At Ttukseom Han River, I saw two guys in suits ask if they could join the picnic mat next to ours. No persona research, no market research, no team. I planned, designed, and built it alone, and shipped iOS, Android, and web simultaneously in 3 weeks.
When the slow app got fast, sign-ups doubled.
Turned a month-plus agency-dependent cycle into a same-day, in-house operating cycle.
When the slow app got fast, sign-ups doubled. Lighthouse 33 → 65, sign-ups 1.08M → 2.10M. A story of tech debt cleanup turning into business growth.
Stepped out of the simple "senior service" framing and learned that care is a network.
To really understand your users, you have to stand in their shoes, I didn't learn this from a book, I learned it wearing a helmet on a delivery run.
"User experience is a brand's first impression", one person, one month, turned a stiff corporate identity into something warm.
Joined as a full-time backend engineer for 1 year and 3 months. Solo-designed and built the core inventory-sync module on CQRS, and offloaded the high-traffic bulk product-registration workload, hundreds to thousands of listings across multiple marketplaces at once, onto an SQS + Lambda async pipeline, raising both stability and throughput.
"Technology only creates real value when it speaks the language of the domain", replacing a 10-year-old ASP legacy with Java 17 wasn't a tech problem; it was a fieldwork problem.
"Moving the offline experience online, that's real web development", 30% more visits, 50% more franchise inquiries.
"Designing only for the reward structure brings participation but loses trust", as the product owner, from planning to deployment, I learned how to design trust.
Consulting agency, over four years, won and delivered 12+ enterprise and public-sector projects for clients including GS Caltex, LG, KTO, Samsung Fire, and KB. Recognized as an official Wanted Premium Freelancer.
Backend development for "Oneseller," an integrated shopping-mall management SaaS, seller tools and a messaging architecture on CQRS, SQS, and Lambda.
Backend development for "Come Visit the Market," a traditional-market online delivery platform, a three-sided O2O system spanning merchants, consumers, and riders.
Worked as a foreign dealer at Parq Casino in Vancouver, Canada, for roughly two years. Serving guests from around the world every night sharpened my global communication skills and service-industry instincts, the experience that ultimately pushed me toward a developer career. (Dates approximate, verification pending.)
GS Caltex EnergyPlus app · The first oil-refiner app to win international design awards
Completed a full-time bootcamp after returning to Korea. Studied backend fundamentals on Java, Spring Boot, and MySQL — which led directly to my first job at Market Tree. Bootcamp portfolio: https://www.youtube.com/watch?v=KV3rapFUXTw (Dates approximate — verification pending.)
Built expertise in the service industry within an international environment and developed global communication skills.
Withdrew while majoring in Civil Engineering after rethinking my career direction. What followed — Marine Corps service, language study in Canada, and service-industry work — became the starting point of my switch into a developer career. (Dates approximate — verification pending.)
Graduated from a general high school in Seoul. (Dates approximate — verification pending.)