Skip to content
yceffort
PostsSeriesTagsAboutπŸ§ͺ Research
KO

Tweaks

theme
accent palette
film grain
minimal mode

FRONTEND ENGINEER AND WRITER

yceffort.

A record of the experience I gained by building and running things.

root@yceffort.kr β†—GitHub β†—
AboutResume

EXPERIENCE AND CONTRIBUTIONS

From building services to the ground a team works on.

I have built and run software across many domains since 2014. I have led a frontend team and built libraries and tools shared by many services. I pass on what I learned through books, writing, and open source.

Frontend engineer, currently employed

Building services
React, TypeScript, Next.js
Operations and performance
Node.js, Kubernetes, web performance
Team foundations
Shared libraries, CLIs, code review
01Experience02Publications03Open source04Beyond work05Education

Experience

Experience from the places I have worked.

  1. NAVER Financial

    2020.09 to 2026.03

    Frontend Engineer, Card FE Lead

    Built financial services and the shared foundation of the frontend organization

    • Built mobile financial services including MyData, member authentication, and the card tab
    • Moved services from SPA to SSR, and designed, deployed, and operated them on Next.js, Koa, and Kubernetes
    • Built and maintained the shared ESLint config and plugins, a state management library, and the design system
    • Made a project scaffolding tool, Node.js CLIs, and MCP servers for everyday productivity
    • Led code review and mentoring on the team, and built and published shared npm packages

    React, TypeScript, Next.js, Node.js, Kubernetes, pnpm, Turborepo

    See the public packages β†—

  2. Triple

    2019.05 to 2020.08

    Frontend Engineer

    Built a travel web service that runs from discovery through booking and payment

    • Built and operated global city search and flight ticket sales
    • Migrated the payment service and shared components from JavaScript to TypeScript
    • Built a one-to-one chat service between sellers and customers

    React, TypeScript, Next.js, Koa, Docker, Amazon ECS

  3. Kakao

    2016.09 to 2019.05

    Software Engineer

    Built and operated the frontend and server of Kakao Together, a donation platform

    • Migrated a legacy AngularJS application to Angular
    • Built admin tools and operated the Ruby on Rails server alongside them

    Angular, TypeScript, Ruby on Rails, MySQL, Redis

  4. Samsung SDS

    2014.03 to 2016.06

    Software Engineer

    Built global healthcare solutions and proofs of concept for new technology

    • Built an EHR solution for overseas hospitals and a nursing ward service
    • Built iOS beacon based indoor navigation and a blockchain PoC for a financial client
    • Validated data consistency and integrity with Python

    Delphi, Oracle DB, Spring, JavaScript, Python

Publications

  • Author

    Frontend Performance Optimization Deep Dive

    From the network to the browser and frameworks, the principles behind performance

    Publisher page (Korean) β†—
  • Co-author

    npm Deep Dive

    Module systems, package management, and the JavaScript ecosystem

    Publisher page (Korean) β†—
  • Author

    Modern React Deep Dive

    How React works and how to build web applications with it

    Publisher page (Korean) β†—
  • Translator

    React Interview Guide

    React knowledge through questions and answers

    Publisher page (Korean) β†—

WRITING NOWWho Learns the Judgment That Remains β†—An essay on developers, judgment, and learning in the age of AI. Working title, in progress (Korean).

Open source

  • Developer tool

    coldpath β†—

    A Rust CLI that traces JavaScript bundle bytes back to their original sources with source maps and V8 coverage. It separates code that runs on load from code that runs only on interaction, and produces bundle treemaps and pull request comparisons. Analysis runs offline, without Node.js or a browser.

    • #rust
    • #source-map
    • #v8-coverage
  • Fork and extension

    number-flow β†—

    A fork of barvian/number-flow that makes its number animations work in older browsers and webviews. It keeps the original API, adds a fallback engine built on requestAnimationFrame, and was verified on real legacy browsers.

    • #typescript
    • #javascript
    • #react
    • #web-component
  • Webview debugging

    storage-inspector β†—

    A Lit web component for inspecting and editing localStorage and sessionStorage inside a webview. Each key gets a description and type from a schema, and values are validated as you edit them.

    • #typescript
    • #lit
    • #web-component
  • Developer tool

    rust-markdownlint β†—

    A Markdown linter written in Rust that aims to be compatible with markdownlint-cli2. Its diagnostics and auto-fixes were checked against the original tool, and it runs on the repositories I maintain.

    • #rust
    • #rayon
  • macOS app

    yc.clipboard β†—

    A macOS menu bar app for searching and reusing your clipboard history, including text, images, and files. It supports pinning, previews, and pasting back into the previous app.

    • #swift
    • #swiftui
    • #appkit

Beyond work

  • 2024

    Talk at DAN24

    Spoke about optimizing the bundle size of web services.

  • 2021.01 to 2021.12

    SSAFY mentor

    Supported young developers at the Samsung Software Academy For Youth by answering programming questions and writing columns.

  • 2018 to present

    Tech blog yceffort.kr β†—

    I build and run this blog myself, and write about framework internals, performance and operations, developer tools, and working with AI.

  • 2016.03 to present

    Board member, JUMP (nonprofit) β†—

    I help with work automation on Google Cloud Platform and with programming education.

Education

  • 2018.03 to 2020.02

    KAIST

    M.S., Graduate School of Management of Technology

    Highest Honors, GPA 4.23 / 4.3

  • 2007.03 to 2014.02

    Dongguk University

    B.A. in International Trade, double major in English Interpretation and Translation

mailMail icongithubtwitter
yceffort
β€’
Β© 2026
β€’
https://yceffort.kr