Frontend Engineer

About the work

I build internal web tools with React and TypeScript so operators, QA, and support teams can repeat work with stable state, clear input contracts, and visible verification steps. Recent work includes FC Online account lookup and edit flows, server-state refresh, gRPC test UI, Content Manager validation, and build cost reduction.

Location: Seoul, Korea
Active: Jul 2023 - present
Open source: 10 PRs in official releases
Primary stack: React, TypeScript, Next.js

Experience timeline

Career

Mar 2025 - Present
EA Korea
FC Online operations tool
Aligned account lookup and edit screens around URL state and React Query cache so QA can reopen the same screen state.
- Kept forms, URL params, and internal validation tools on the same TypeScript and Zod input contract; refreshed nine stale-after-mutation flows.
- Grouped Content Manager validation and a gRPC test UI inside the operations tool; reduced entry JS gzip from 195.9KB to 111.1KB through Vite 8, chunk, and preload changes.
May 2024 - Mar 2025
NHN Injeinc
Ticketlink
Preserved filters and scroll context across list, detail, and reservation screens with React Query cache.
- Reduced loop-swipe rendering and painting events from 156 per second to 32 per second.
- Mitigated long-list crashes on older iPhone Safari and raised sub-20fps sections to an average above 50fps.
Jul 2023 - May 2024
PandoraTV
Cobak, crypto community
Refetched payment and membership state after app payment-completion notifications to prevent duplicate requests and stale status.
- Designed a draft autosave flow with a backend developer so long posts survive app exits and back navigation.
- Separated public search-entry pages behind a Next.js SSR boundary and migrated 100+ files from JS to TS and React 16 to 18 by feature.

What I care about

Flows that let operators and QA reopen the same state
Input contracts shared by forms, URLs, and test tools
Regressions caused by browser and runtime differences
Open-source PRs that landed in official releases

Evidence

Merged open-source work

PRs that landed in official releases across performance, SSR regression tests, runtime compatibility, type safety, and CI stability.

#8641TanStack Query
Optimized useQueries from O(N²) to O(N)
Reduced function calls in the 500-query benchmark from 4,500 to 2,000 (about -55%).
#9592TanStack Query
Fixed persist + memoized combine bug
Resolved stale UI after page refresh.
#9623TanStack Query
Fixed CI timeout
Stabilized a mismatch in the Nx Cloud distributed execution config.
#14286React Router
Fixed missing middleware skipRevalidation handling
Prevented unnecessary parent loader re-executions.
#14335React Router
Handled restricted browser storage environments
Added safe handling for session save failures in private mode.
#14534React Router
Fixed fetcher.submit JSON bug
Added regression tests for SSR environments.
#14336React Router
Fixed generatePath suffix parameter handling
Resolved failures generating :id.json paths.
#14687React Router
Added crossOrigin attribute to <Links />
Mitigated CSS preload failures and cache conflicts in CDN CORS environments.
#12865React Hook Form
Fixed useController type regression
Resolved the never-lock issue and added type tests.
#3611TanStack Router
Fixed params.parse notFound() handling
Changed 500 to 404 behavior and added tests.

Impact at a glance

Official-release PRs: 10
Career chapters: 3
Active since: 2023.07
Primary stack: React

What I reach for

React, TypeScript, and Next.js as a base. TanStack Query, React Router, and Zustand for state and routing. Vite, Vitest, Playwright, and ESLint to keep build and tests honest. Node, Fastify, Prisma, and tRPC when I need a backend.

Core: React, TypeScript, Next.js
State/routing: TanStack Query, React Router, Zustand
Build/test: Vite, Vitest, Playwright, ESLint
Backend: Node, Fastify, Prisma, tRPC