Portfolio | Seung-Ju Oh

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I work across frontend, backend, infrastructure, and cloud to understand and design the full service flow.

01 / Selected work

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Unicorea · 2026.04–Present

Payment and Settlement Service Development

Full-Stack Engineer

Developing merchant web, settlement APIs, and shared deployment operations

React, TypeScript, Kotlin, Spring Boot, Kubernetes

크림쿠키스튜디오 · 2026.03–Present

Daechang Brassone Web Development

Web development

Web development with Next.js

Next.js

Personal open-source project · 2026.03

Coupang Review Draft Assistant CLI

Implemented a browser-based review-drafting assistant CLI

Connects to a Chrome remote-debugging session and waits for manual sign-in
Extracts product context from review pages and separately generates seller-service and product-review drafts
Validates generated text before filling the review form

TypeScript, Node.js, Puppeteer, OpenAI/OpenRouterSource ↗

V2C Co., Ltd. · 2025.11

Muju Healthcare Admin Frontend Development

Developed admin web frontend

Built admin operation screens

Next.js

Korea Pharmaceutical and Bio-Pharma Manufacturers Association · 2025.07 - 2025.10

KPBMA Digital Archive Development

Developed website and digital archive

Implemented dynamic archive management by auto-generating detail pages with Node.js

HTML, CSS, JS, NodeJS

Veterans / Dmonster · 2025.01 - 2025.03

Veterans Backend Development

Developed backend for education platform admin

Built admin backend using NestJS

NestJS(TypeScript), Prisma

Current public promotional dashboard image for ENSolution. — Current public service image, viewed 2026-09-23ENSolution public site

EN Media · 2024.10–2025.09

ENSolution Development

Developing a marketing solution

Implemented visitor tracking and crawler for search/place/shopping channels
Implemented automated report publishing
Built payment flow with Toss Payments
Built automated re-registration and auto-bidding for Naver keywords/assets

Next.js(TypeScript), Spring Boot(Kotlin), AWS Lambda(Node.js), K8S, AWSWeb ↗

Korean Association / Dmonster · 2024.08 - 2024.09

Korean Student Association Upgrade & Server Migration

Upgraded operations and migrated infrastructure

Migrated PHP-CGI to PHP-FPM
Migrated Apache to Nginx
Migrated CentOS7 to Amazon Linux 2023
Switched outbound mail to Gmail SMTP
Improved security/operations features (captcha, drag-block, per-board editor)

PHP, 그누보드, AWS EC2Web ↗

Personal open-source project · 2024.08

React Native Action Sheet

Implemented a React Native action-sheet library for iOS and Android

Provided an ActionSheet API for titles, messages, and button configurations
Included Swift/Objective-C iOS modules and a Kotlin Android module
Configured the package to build CommonJS, ESM, and TypeScript declarations

React Native, TypeScript, Swift, Objective-C++, KotlinSource ↗

Hanuri / Dmonster · 2024.07 - 2024.08

Hanuri IoT Application Development

Developed IoT-integrated mobile app

Implemented Bluetooth-based front detection and gyro-sensor alerts

React Native, BluetoothAOS ↗iOS ↗

Personal open-source project · 2024.05

OpenAPI Generator

Implemented a CLI that generates TypeScript interfaces from OpenAPI schemas

Fetches schemas from OpenAPI URLs declared in a configuration file
Generates namespaces and TypeScript interfaces from schema names
Writes package metadata alongside generated output

TypeScript, Node.js, Rollup, PrettierSource ↗

JEP / Dmonster · 2024.04 - 2024.08

JEP World E-commerce Development

Built user/seller/admin web and backend

Built website with Next.js
Built backend application with Spring Boot

Next.js, Spring Boot, MySQL, 스윗트래커, 다날 결제모듈

AEND Co., Ltd. · 2024.04

Prostate Self-Diagnosis Survey Site

Built survey website

Built survey site with React
Built admin side with PHP GNUBoard

React, PHP, 그누보드Web ↗

Tinker / Dmonster · 2024.03 - 2024.04

Tinker Admin Backend Development

Built shopping mall admin backend

Designed and implemented admin APIs with NestJS

NestJS, TypeORM

Chungho Nice / Idenit · 2024.01 - 2024.03

Chungho Nice CS PHP Development

Developed full Chungho customer center

Built and operated customer center features on PHP 5.2

jQuery, PHP 5.2, Oracle, KG 이니시스 결제 모듈Web ↗

Majangdong Sky Livestock / Idenit · 2023.11 - 2023.12 (about 1 month)

Majangdong Sky Livestock Admin Development

Developed admin web

Implemented ordering flow linked with Naver products and QR codes

React, Antd, Spring Boot, AWS S3, Elastic Beanstalk, CloudFront, NCP SMS

TopPeople Co., Ltd. · 2023.10 - 2023.11 (about 1 month)

PeopleT Map Feature Development

Developed map feature using KakaoMap

Built map UI in React app
Integrated map via React Native WebView

React Native, React, Tailwind CSS, KakaoMap API, Node, Express

Shinsegae I&C / Actbase LLC · 2023.06 - 2023.09

Shinsegae SSG EDU LCMS Renewal

Handled PM and development (API, Web, DevOps)

Containerized Spring Boot API and deployed to EKS
Built/exported Next.js web and delivered via S3 + CloudFront
Implemented LCMS with SCORM and xAPI
Implemented S3 upload/chunk upload/download
Implemented JWT access/refresh tokens with Redis-based refresh token management

Next.js, React, Spring Boot, SCORM, xAPI, AWS EKS, CloudFront, S3, Route53, RDS, ElastiCache

Personal work · 2023.03

Storage API

File-storage API tool

Built upload, metadata lookup, file delivery, and image-variant cache flows

NestJS, SharpSource ↗

Personal work · 2023.03

UI Library

React component and Storybook documentation experiment

Experimented with typed UI components and Storybook documentation

React, TypeScript, SCSS, StorybookSource ↗

Maybeone / Actbase LLC · 2023.01 - 2023.04

Bizprint Renewal

Led front-end development

Built frontend and CMS with Next.js

Next.js, React

SKKU IMBA website displayed on a desktop monitor, from an earlier portfolio. — Archived portfolio screenArchived portfolio PDF

Shinsegae I&C / Actbase LLC · 2023.01 - 2023.03 (about 3 months)

SKKU IMBA Renewal

Developed front-end, CMS, and API

Built web and CMS with React
Built API server with Spring Boot JPA

React, Next.js, Spring Boot

Shinsegae I&C / Actbase LLC · 2022.07 - 2022.12 (about 6 months)

Pangaia SPVRKD Development

Led overall project development

Built the app with React Native
Built Node.js server with Express/Sequelize
Built Next.js frontend and deployed serverless on AWS S3/CloudFront/Lambda
Built React-based CMS and deployed to AWS S3/CloudFront
Set up production, staging, and development environments

React Native, Next.js, React, Express, Sequelize, AWS S3, CloudFront, Lambda

2022.07 - 2023.01 (about 7 months)

mKWP App Maintenance

Maintained mKWP app with React Native

Maintained mKWP app built with React Native

React Native

Aikuka / Actbase LLC · 2022.06 - 2022.06 (about 1 month)

Aikuka Enhancement

Developed Aikuka app with React Native

Built Aikuka mobile app with React Native

React Native

Two HomeGrit mobile app screens, from an earlier portfolio. — Archived portfolio screenArchived portfolio PDF

Kang & Kim Partners / Actbase LLC · 2022.03 - 2022.12 (about 10 months)

HomeGrit Development

Led overall project development

Built HomeGrit app with React Native
Built HomeGrit CMS/Partners with React
Built API server with Spring Boot JPA/QueryDSL
Set up production and development environments

React Native, React, Spring Boot, JPA, QueryDSL

Personal work · 2022.01–2023.05

SANA Portfolio

Full-stack personal portfolio implementation

Built a Next.js frontend alongside a NestJS server
Implemented authentication, profile, and portfolio create, update, and delete APIs and screens
Recorded responsive portfolio, about, and contact pages plus Docker configuration in public source

Next.js, TypeScript, NestJS, TypeORM, PostgreSQL, DockerSource ↗