Yeonggyun Kim

Yeonggyun Kim

Web Frontend Engineer in Seoul

Projects

2024

An advertising product that people can upload their short-form videos and link to their own site.
To show how their video source displayed in our main feed, I created an preview component as same as native app view.

However, we also achieved big improvement of our code base such as migrate build system, refactoring network controller and bump many other dependencies. This work makes our team's development experience much better.

  • Typescript, React, vite, tanstack-query, zustand, vanilla-extract
2024

Viral marketing dashboard page. It helps people signup the promotion and check their progress.

Especially focused on app landing using universal link and web page performance.

Achieved 1,000% of ROAS.

  • Typescript, Next, SSR, tanstack-query, tailwind-css
2024

Rebuild AD manage service to responsive layout not only mobile webview platform, but also PC desktop view.

We created and replaced many components both supports various width of PC and Mobile devices.

Build BFF server to support GraphQL API gateway.
The api services are created automatically based on open api spec.
BFF aggregates all other backend api servers and makes them as a GraphQL resolver.
We build an optimized client schema and it works as a flexible layer to server side changes.

  • React, Typescript, Vite, GraphQL(relay), zustand, vanilla extract.

  • Typescript, Fastify, graphql-yoga, graphql-envelop, Docker

2024

Building new web site of Karrot Business.
It has landing pages of our several services, and blog.

To update content easily without engineer's hand, I used CMS to this project.

The site was linked by NextJS's rewrite feature, to keep previous SEO results by using same domain and paths.

  • Typescript, Next.JS, SSR, GraphQL, Sanity CMS, Vanilla-extract

  • Tracking SEO metrics, and organizing sitemaps

2024
Low quality AD thumbnail notice at Karrot

Let users know their advertisement source has low quality of image like too small size, don't have any context with the content, or too many text in the image.

To check the quality of thumbnail image, we used AI powered solution based on Google Vision API.

  • Achieved 36% of users who seen the message changed their thumbnail more good quality and get better ad performance.
2024
Onboarding user marketting agreement process improvement at Karrot

Improve flow of marketing agreement more user friendly changing steps, adding bottom-sheet component after signup component.

  • Achieved new agreement more than 200 people per day, 9% of actual user who didn't allow.
2023

Make an QR code generate and manage service to connect local store and customers. The owner of store can link their homepage to random generated QR codes and printed it in front of counter; like banner.
People who visit the store can subscribe the store's news and get benefits easily.

I developed both mobile webview client pages and QR code validation API servers.

  • Typescript, React, Vite, vanilla-extract, Cloudflare Pages,

  • Node.JS(Hono), Zod, Cloudflare KV, Cloudflare Workers.

2023
External WEB landing AD product at Karrot

An advertising product that supports advertise their own homepage to our app service.
To make this new product based on our service, we tried to refactor our service structure and remove many legacy code lines.

  • Migrated legacy recoil based structure to zustand. it makes easier state change tracking and make crystal clear the origin of source.
2023
Karrot AD landing SDK at Karrot

An react component package that encourage people to advertise their shops and make it easy to see the results. This components have used in other services in our company.

We could make AB test to this component and learned which UI is effective to engage people.

2022

Build Karrot Business PC web site.

  • Developed Karrot business service

  • I developed advertising part of Karrot Business. It serves same feature of our webview service, running and configuring ads, managing ad performances.

  • Run several A/B testings.

  • Apply Google Analytics, Microsoft Clarity to analyze user actions.

  • Typescript, React, tanstack-query, recoil, stitches.

2022
Rebuild of AD managing webview service at Karrot

I re-builded whole part of our advertisement manage service.

  • Webview Based Service of Karrot.

  • Apply new design system of our company, Seed-Design

  • Completely rebuild project based on React Typescript.

  • Build CI/CD pipeline using Github Actions, to AWS S3.
    At first I tried to using Netlify, Cloudflare pages, to solve few problems, I finally selected AWS S3 as our serving platform.

  • Connected Google Analytics, Datadog RUM, to analyze User Action.

  • Typescript, React, GraphQL, Relay, Recoil

2021
AD service landing page at Karrot

I developed new landing page of our service.

Tech Stacks
Typescript, React, GraphQL, Stitches, Gatsby, SSR.

2021
Domoverse at Samkrion Inc.

After release of MVP product, we found our new supporters and founders.
We continued to our product and made decision of migrate to new tech stack - React Native.

  • Developed New App Client, named as Domoverse(도모버스) using React Native

  • Applied Microsoft CodePush service to make live patch of our client app. It reduced update delay time and serves our new feature right away.

  • Developed OCR feature to automatically recognize user's report card using Clova OCR.

  • Developed In-App-Purchase feature.(Apple, Google Play)
    We had both one time purchase items and monthly subscriptions.

  • Developed app push service using Google Firebase

  • Construct CI/CD pipeline using Fastlane and Github Actions.
    It makes different build artifacts depends on build flavor, environments.
    Using "Fastlane match" service, we can manage our iOS Signing Key centralized. It helps sync the keys between engineers.

  • Developed Chatting feature using Channel Talk.

  • Tech Stacks
    Typescript, React, Redux, React query
    Microsoft AppCenter, Firebase, FastLane, Datadog

2020
Domo at Samkiron Inc.

I joined as a client product engineer; however, I solved many technical challenges across various domains.

  • Release MVP product of our service "DOMO(도모)", using Ionic React to support multi-platform.

  • Apply Datadog RUM and Google Analytics to analyze our customers and improve UX.

  • Apply Google, Facebook, Kakao SSO

Side Projects

2020

Personal Side Project

  • 202 DSC Solution Challenge

  • An app that helps you take medications safely by searching for possible interactions when taking multiple medications together.

  • Kotlin, Android

2019

School shuttle bus information service

  • Backend (Express)

  • Frontend (Vue, PWA, Migrated to React)

  • CI/CD (Jeknins, Google App Engine, Google Cloud Builder, Docker)

2019
HYBUS

School shuttle bus information service.

  • Supports connecting public transportation info using OPEN API

  • Flutter

2019
TradeDog

Frontend Engineer

  • Capstone Project (CoinOne, Hanyang Univ. ERICA)

  • Cryptocurrency Trading Info Dashboard

  • Vue.JS

Work Experience

2021 — Now
Seoul, South Korea

Work as a Frontend engineer at Karrot.

As a member of advertising business department, I solve many business problem using engineering tech skills.

2020 — 2021
Seoul, South Korea

I joined to make whole part of client side product; however, I solved many technical challenges across various domains.

  • Developed cross-platform MVP product with Ionic, React and Cordova.

  • Developed initial release product with React Native.

  • Developed web back-office product. (React, Typescript)

  • Build CI/CD environment with Fastlane.

2016 — 2018
Full Stack Engineer at Korea Defence Security Army
South Korea

Serviced as web fullstack engineer

  • Work as CERT member.

  • Javascript, PHP, MySQL

Education

Contact

LinkedIn
GitHub