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• - Software Engineer @ Contents Technologies

  2026.04 ~

  • TypeScript
  • Solid
  • Rust
  • DataFusion
  • StarRocks

  Rejoined Contents Technologies, a company operating various businesses based on music IP, as a full-stack engineer.

  Building on the Solid-based frontend and Rust backend foundation I established during my previous tenure, I contribute across the board, spanning frontend, backend, infrastructure, and data pipelines.

  • Agent Skill-based AI prototype refactoring workflow Prototypes built by product managers with AI had to be manually refactored by developers to match codebase conventions every time they were merged into the product codebase. To solve this, I documented best practices such as state management and code structuring conventions using Solid and Bunja, along with shared component design conventions, as Agent Skills, establishing a workflow where prototypes can be refactored by actively leveraging AI.
  • DSP analytics data processing pipeline The music distribution business needed to process large volumes of analytics data delivered by each DSP. To minimize memory usage and maximize throughput, I built a streaming-oriented data processing and loading pipeline using Arrow, Parquet, and DataFusion. When loading data into StarRocks, I also structured a layered data modeling architecture using Async Materialized Views.

• - Software Engineer @ The Guild

  2025.09 ~ 2026.02

  • TypeScript
  • React
  • GraphQL
  • PostgreSQL

  Worked as a full-stack engineer at The Guild, a company operating a GraphQL schema registry SaaS.

  As a full-stack engineer, I worked on dashboard product features and led a structural migration of the account system.

  • Account Linking implementation The OSS version of SuperTokens does not support Account Linking, which caused unnecessary duplicate accounts to be created for each sign-in method. To solve this, I implemented Account Linking at the application layer, bypassing SuperTokens, and merged existing duplicate accounts by writing a DB migration script that correctly handles every edge case identified through analysis of real production data.

• - Software Engineer @ Contents Technologies

  2024.07 ~ 2025.08

  • TypeScript
  • Solid
  • Rust
  • GraphQL

  Worked as a full-stack engineer at Contents Technologies, a company operating various businesses based on music IP.

  While filling gaps in the Solid ecosystem, the company’s primary framework, by building foundational pieces such as a router and a data layer myself, I developed mobile and web apps for a new business and rewrote the legacy stack of an existing business.

  • Mobile WebView app development and desktop web app transition With Solid adopted as the organization’s primary framework, I ported Stackflow to Solid to implement stack navigation in the mobile app, and developed a plugin to add desktop support. This enabled a single codebase to use stack-based navigation on mobile and nested routing on desktop, improving productivity.
  • Rust-based GraphQL backend API development I established best practices for schema design and code structure, and forked the GraphQL server framework to implement the latest Semantic Nullability proposal. This work was later merged into and used by 1Password’s internal fork as well.
  • Music distribution infrastructure rewrite I ran PoCs of OLAP databases such as StarRocks and ClickHouse to implement real-time analytics, developed the zero-copy-oriented lazycsv crate when a high-performance CSV parser became necessary for processing royalty settlement data, and built and adopted Solid Relay, a Solid binding for Relay, to follow GraphQL best practices in the Solid web frontend.

• - DX Engineer @ PortOne

  2022.10 ~ 2024.07

  • TypeScript
  • React
  • GraphQL
  • Vite
  • Solid

  Worked as a frontend/DX engineer at PortOne, a company building payment-related SaaS products.

  As a DX engineer, I contributed across the board, from the payment SDK used by customers’ developers to the foundational tooling of the internal FE chapter, focusing on improving the development experience and performance both inside and outside the company.

  • JS payment SDK performance and maintainability improvements The existing SDK was a single script with a jQuery dependency, suffering from degraded maintainability and a growing bundle size due to continued unstructured development. To solve this, I led the entire process, from raising the issue through execution and verification, of removing the jQuery dependency and designing a custom SWC/esbuild-based module system that enables per-feature lazy loading without ESM (for IE11 support). This reduced the bundle size by over 100KB, and the modularized codebase significantly sped up the whole team on tasks such as integrating new payment gateways.
  • Custom checkout UI rewrite The existing checkout UI was a React SPA with initial loading performance issues. Judging that edge streaming SSR and server RPC would best solve this, I adopted SolidStart, the framework with the best support for those features at the time. As a result, it achieved an FCP of around 0.3 seconds under typical conditions, and reliably handled over 300,000 payment requests per month.
  • Admin console development environment improvements The existing console used Next.js SSG despite functioning almost like an SPA, causing productivity issues such as slow builds and having to unnecessarily account for SSG during development. To solve this, I migrated the entire product to Vite, achieving results such as shorter build times. I also improved the development environment overall, such as upgrading outdated dependencies like Storybook and TypeScript, and introducing UnoCSS with a compatibility layer as an alternative to the Sass + CSS Modules styling that had become a headache due to soaring complexity and cumbersome usage.
  • Led company-wide GraphQL/Relay adoption While discussing the introduction of an API Gateway on the MSA to improve FE DX, I proposed and actively led the adoption of GraphQL/Relay based on its frontend-side strengths such as normalized caching. To ensure a smooth adoption within the team, I ran onboarding sessions for chapter members, established the code structure of the Scala-based GraphQL Gateway server, and integrated SSE-based @defer support for Relay to leverage Concurrent Features, enabling every team member to work with GraphQL without difficulty.
  • Custom SVG chart component implementation While developing a new analytics service, I implemented SVG chart components from scratch to meet the feature and UX requirements from product and design, such as responsive design, animations, and sticky axis labels. Through appropriate use of Framer Motion and scroll virtualization, I minimized performance degradation even with large datasets, and the reusability-focused design allowed the same components to be shared across other pages later on.

• - Full-stack Developer @ NutritionCourt

  2020.09 ~ 2022.10

  • TypeScript
  • Vue
  • Flutter
  • GraphQL
  • AWS
  • Kubernetes
  • React

  Worked as a full-stack developer at NutritionCourt, an AI healthcare startup.

  Due to the nature of a small startup, I worked across various areas from frontend to backend, mobile apps, and infrastructure. In the later period, I filled the gap left by the departure of the senior backend developer by taking the lead on the backend, while also onboarding junior frontend developers and distributing work to collaborate with them, working as a full-stack developer.

  • Healthcare web product rewrite in Vue/Nuxt I rewrote an Angular 2-based MVP web app in Vue 2, and a B2B product consisting of a desktop web for doctors and a mobile web for patients in Nuxt 2 with SSR optimizations, while also maintaining the Python/Falcon API backend.
  • Solo development and maintenance of the Welcoach mobile app I joined as the sole developer of Welcoach, a Flutter app that analyzes National Health Insurance Service checkup data to provide personalized food and supplement solutions, shipped it to the Play Store, and reached over 1,000 downloads. I continued maintenance afterwards, including features such as simplified authentication via native module integration.
  • Welcoach Shop MSA GraphQL backend I built an MSA backend for extending the Welcoach Shop Shopify store as a single Schema Stitching-based GraphQL API on Kubernetes, and implemented the entire flow from purchasing a checkup product to delivering the report through partner API integration.
  • Shopify customization and web frontend development I customized the Shopify store with Liquid and Svelte, developed the questionnaire and report pages with Vilay, a Vite-based SSR framework I built myself, and mentored junior developers along the way.