Jahun Koo

Jahun Koo

Software Engineer

Seoul, South Korea

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I'm Jahun Koo, an engineer who finds fulfillment in creating a new future through programming.
Throughout my career, I have opened up new business opportunities as an engineer. The AI era is no different — keeping pace with the speed of change, I'm building the future together with AI as a colleague. I hope to meet great people and build a better future together.

  • Co-founded a global startup
  • Experience leading an AI Native development culture and agent engineering
  • Extensive experience designing, developing, and operating frontends for web/app services
  • Strong understanding of UI/UX and user interaction from building multiple design systems
  • Experience collaborating with PMs, designers, backend engineers, and QA
  • Quick to adapt to and learn new technologies

Technical Skills

  • Typescript, Javascript
  • Next.js, React, React Native
  • HTML, CSS, Less, Sass, styled-components, tailwindcss
  • Node.js, MySQL
  • Context Engineering, Agent Orchestration
  • AWS, Firebase, Supabase, Convex
  • Git, Github, rush

Work Experience

Engineering Manager & Frontend Engineer, Coxwave

2025.02 ~ Present

AI Native Team Leadership (Engineering Manager, 2026.04 ~)
  • Built an AI Native organizational culture and led hiring
  • Led planning and development of a new agent service
  • Built a leadership workspace that runs team-lead duties (1:1s, evaluations, hiring) on agents
Align Product Development & Operations (Frontend Engineer, 2025.02 ~)
  • Developed and operated a solution that analyzes conversations between AI and users to deliver insights
Main Languages & Technologies
  • Typescript, React, Next.js, Node.js
  • Context Engineering, Agent Orchestration

[Freelancer] Senior Frontend Engineer, Aivelabs

2023.09 ~ 2024.10

CRM Tool — SaaS Version
  • Built a SaaS targeting Cafe24 merchants
    • Converted the previously built B2B web-based CRM App into a SaaS
    • Implemented onboarding for Cafe24 merchants
    • Integrated the Toss Payments billing module
    • Added a landing page
    • Implemented the frontend for Kakao carousel-type campaign messages
AI CRM Tool
  • Overall frontend development of the B2B web-based CRM App
    • Implemented a design system for a consistent UI/UX
    • Implemented JWT-based authentication
    • Built a view that shows multiple mobile screens side by side to manage customer-tailored campaign messages
  • WYSIWYG editor for mobile content
    • Rendered GPT-generated content in the WYSIWYG editor
    • Added editor components so users can easily compose content
    • Deployed mobile content written in the editor to a static server
  • Implemented the frontend for creating and managing campaign messages (SMS, Kakao Alimtalk, Kakao Friendtalk)
Main Languages & Technologies
  • Typescript, React for view framework
  • react-router for client side routing
  • axios, swr, zustand for state management
  • react-hook-form, yup for form validation
  • bootstrap, rsuite, sass, styled-components for styling
  • lexical for handling wysiwyg editor
  • fetch-event-source for server-sent event
  • github action for CI/CD pipeline
  • AWS S3, Cloudfront for static file hosting

[Freelancer] Fullstack Engineer, Anapavo

2023.02 ~ 2023.05

Mobile Prototype App for an A-CBT Service
  • A prototype built to collect feedback on a self-acceptance service from specific customer groups
  • Implemented the minimum prototype requirements within a limited timeframe using the Ionic framework and Firebase
Main Languages & Technologies

Co-founder & Frontend Lead, Swingvy.

2016.10 ~ 2022.07

Frontend Lead of a SaaS-based HR Platform
  • Built and maintained the React-based web app
  • Built and maintained the design system
  • Localized the service for each market
  • Built the automated FE deployment pipeline
  • Migrated project management to a monorepo as the number of projects grew
    • HR & leave management service
    • Payroll service
    • Expense claim service
    • Time management service
  • Maintained the React Native mobile app
Main Languages & Technologies (CSR webapp, React Native mobile)
  • Language: Javascript, Typescript
  • Frameworks: React, React Native, Expo, Backbone
  • State management: redux, react context, react-query, zustand
  • Styling: Less, styled-component
  • Bundling & version control: webpack, babel, git
  • CI/CD: jenkins, AWS pipeline, S3, cloudfront, github action
  • Monorepo management: rush.js, lerna & yarn

Android Developer, Watcha

2015.06 ~ 2016.06

Watcha Play Android App — Development & Launch
  • Owned Android on the Watcha Play project from kickoff to a successful service launch
  • Continuously shipped user feedback to the app through two-week sprints after launch
  • Handled asynchronous user interactions of the video player per scenario using RxJava
Watcha Android App Maintenance
  • Localization for the Japanese service launch
  • Supported the Watcha 3.0 major update and added new features
Main Languages & Technologies
  • Java, Android, RxJava

Software Engineer, GetBanana.

2013.08 ~ 2015.01

Platform Connecting Tutors and Students
  • Built and launched the Android app from scratch
  • Designed and implemented the server and database
Main Languages & Technologies
  • Java, Android, Java Servlet, MyBatis, Mysql

Activities

Research Fellow, AFHI

2011.04 ~ 2012.12

  • Completed the foresight basic (16th) and advanced courses
  • Contributed to the Future Smart Home report
  • Researched megatrends as a member of Futures Finder (2nd)
  • Worked as a member of Futures Designer (4th)
  • Key skills
    • Environment Scanning, System Thinking, Futures Wheel

Education

NHN Software Membership Preparatory Course, NHN

2012.12 ~ 2013.05

  • Studied the foundations needed as a web developer through the membership program
    • OS & networking, database design, Java web server programming, design patterns, html, css

Kyung Hee University, Seoul Campus

2008.03 ~ 2015.02

  • B.S. in Mathematics, College of Sciences

Languages

  • Korean: Native
  • English: Upper-Intermediate