Hi, I'm
HyoGeun Kim
|
I build fast, well-structured web applications. Most recently, I took a site from Lighthouse 52 to 87 as a solo frontend engineer, and I have a habit of building things from scratch when libraries fall short -- like a custom SVG infinite canvas with raw DOM manipulation.
About Me
I'm a Frontend Engineer with 2+ years of experience, mostly as the sole frontend developer on small teams. I have been responsible for everything from performance optimization and architecture decisions to payment integrations and CMS builds.
At AwareLab, I inherited a site scoring Lighthouse 52 with a 9-second LCP. I brought it to 87 by cutting the bundle 46% with dynamic imports, subsetting fonts from 800KB to 250KB, and fixing race conditions in financial chart rendering. Before that, I studied Computer Graphics as an undergrad researcher (published at CIA 2023) and competed in ACM-ICPC regionals -- which is where I picked up the habit of thinking about problems systematically.
These days I'm focused on FSD architecture for organizing large codebases, Stripe and Directus integrations with full type safety, and building custom editors with TipTap. I like working on products where I can own the frontend end-to-end and make real impact on user experience.
Performance First
Took Lighthouse from 52 to 87. Bundle analysis, code splitting, font subsetting, fixing CLS -- whatever it takes to make the site fast.
Scalable Architecture
I use Feature-Sliced Design (FSD) to keep large codebases organized and maintainable as they grow.
System Integration
Stripe payments, Directus CMS, 3-language i18n -- I wire up complex systems with type safety so things stay reliable.
Experience
Where I have worked and what I built there.
Frontend Engineer
Solo frontend engineer on an investment portfolio analysis platform. The team went from 6 to 4 devs, and I became the only frontend engineer after my colleague was let go.
- Improved Core Web Vitals: LCP 9s to 3.8s (60% reduction), CLS 0.126 to 0, Lighthouse 52 to 87.
- Cut bundle size 46% (253KB to 136KB) using @next/bundle-analyzer to find the worst offenders, then applied code splitting and dynamic imports.
- Set up Feature-Sliced Design (FSD) architecture to keep the growing codebase manageable.
- Built an Admin Dashboard with Zustand Factory pattern for reusable filter stores, RBAC, and TanStack Table.
- Developed a TipTap CMS editor with 12 custom extensions including SlashCommand, Paywall blocks, and Stock chart embeds.
- Fixed race conditions in financial chart rendering -- closures were capturing stale data, solved it with closure scoping + Map-based caching + gsap.context().revert().
- Integrated Stripe (membership, period selection, coupon, payment flow) and Directus CMS with shared types between FE and BE.
- Implemented 3-language support (EN/KO/JA) with next-intl, including hreflang tags for SEO.
Frontend Engineer
Solo frontend developer on a 3-person dev team (CTO, backend, me). Built and migrated products for funeral-related services at a 30-person company.
- Migrated The Prestige from legacy ASP.NET to Next.js (8 pages in 6 weeks). The old site had full page refreshes on every filter change -- I rebuilt it as a SPA with real-time filtering. Alpha testers said it was a much better experience.
- Set up Vercel CI/CD to replace the old manual deployment process (deploy time went from 10 min to 2 min). Previously had to hand off build files because I had no access to the Windows Server.
- Worked with the backend developer to design clean API response structures.
- Built a gift e-commerce site with Vite+React (chose it over Next.js since there was no SEO need). Used LocalStorage persistence to stop users from losing order data when switching between the site and their contacts app for recipient info -- this directly reduced phone-order fallback CS calls.
Frontend Engineer
Selected for the 14th cohort of SW Maestro, a government software talent program.
- Built 'Kumo Factory', a no-code cloud deployment platform where you design infrastructure visually on a canvas.
- Started with react-zoom-pan-pinch but hit canvas size limitations for large architectures. Ended up building a custom infinite canvas with pure SVG DOM manipulation and 3x3 affine transformation matrices. The hardest part was getting pixel calculations right at different zoom levels.
- Achieved 60fps rendering and 30% memory reduction through data normalization and Zustand selective subscribing.
- Reduced unnecessary API calls by 50%+ with a 3-layer state architecture (domain/UI/server).
- Implemented real-time deployment logs using Server-Sent Events (SSE) with <100ms latency.
Frontend Developer
Core member of Google Developer Student Clubs at Seoul National University of Science & Technology.
- Built a shared fridge service for food donations using Next.js 13 and Recoil.
- Integrated Google Maps API for finding and visualizing fridge locations.
- Learned and implemented Optimistic Updates here -- a pattern I later used in production at Daqda.
Technical Skills
Tools and technologies I use day-to-day.
Frontend Core
Styling & UI
State & Data
Forms & Tables
Infrastructure & Tools
Integrations
Featured Projects
Things I have built.
AwareLab Membership
Investment portfolio analysis platform with financial charts, Stripe-powered memberships, and 3-language support. I handle all frontend work as the sole FE engineer.
The Prestige
Funeral home location and comparison service. Migrated the entire frontend from legacy ASP.NET to Next.js in 6 weeks, ahead of a demo for Yonsei Severance Hospital.
Kumo Factory
No-code cloud deployment platform where you design infrastructure visually on an infinite canvas. Built during SW Maestro 14th cohort.
Let's Connect
I'm open to full-time roles or interesting contract work. If you are looking for a frontend engineer who can own the entire frontend independently, I'd love to hear from you.