I am Lee Sangyoon, a full-stack engineer in South Korea. Twelve years, mostly in small teams where one person takes a feature from the spec to production and then answers for it afterwards. I am open to remote contract work and remote roles.
One condition, stated first so nobody wastes time: I work in writing only. Email, chat, issue trackers, pull requests. No calls, no video interviews. If that rules me out, it rules me out early, and that is fair to both sides. What I offer in exchange is a written trail of every decision, an answer within 24 hours, and a plan you can read before you pay for anything.
And the written trail is the part I would keep even if calls were easy. Every request you make and every answer I give stays on the record. A change of scope and what it costs is written down the moment it is agreed, so it is not a memory contest three weeks later. You can search the whole history of the project, and hand it to whoever takes over from you. In my experience most disputes in contract work start with "but we said" about something nobody wrote down.
Work I was paid for
Children's news app (Flutter, iOS and Android), 2024 to 2026. Shipped to both stores. Then rebuilt the backend from AWS Amplify to Spring Boot WebFlux while the app was live, as the only engineer. Because the API boundary was GraphQL, the app shipped no forced update during the migration. Recurring subscription billing through a payment gateway, Google and Apple sign-in, refresh-token auth. After launch: realtime ratings over GraphQL subscriptions, streak rewards, article translation.
Unmanned study cafe system, 2023. The whole thing: web seat booking and passes, an Electron kiosk in the store, an admin for both, card payment with recurring billing, and a door controller wired to pass state so access reflects payment in realtime.
Healthcare platform, 2020 to 2023. Rebuilt a hospital, patient and operator platform on Laravel 8 API plus React. Three role boundaries and SSO, API documented in Swagger so the app team could work in parallel, AWS setup and deploys run by me.
Realtime chat app, 2019 to 2020. Flutter and Firebase, FCM push, SMS-verified signup, in-app purchase with server-side receipt validation. Scaled from one server to four when traffic outgrew the box.
Before that, 2014 to 2019. A gold trading platform and its app, realtime chat and browser games, an eCRF solution for academic conferences, public sector sites, and a lot of commerce builds. PHP, jQuery and the habit of running my own servers came from here.
Side projects, all live, all built and operated solo
- SearchLink (https://searchlink.namubase.com). Connects Google Search Console to Claude and ChatGPT over MCP, mails a weekly report with three things to fix, and alerts when clicks drop. Cloudflare Workers, D1, OAuth, billing.
- Public auction price statistics site. A daily cron pulls a government open API and generates about 350 statistics pages. Workers plus D1.
- Atlassian Marketplace apps. A Jira markdown editor and dashboard gadgets, through Atlassian's security review and publicly installable. Forge and React.
- Marketplace extensions published on WordPress.org, JetBrains, VS Code, Figma and Wix.
- Open source. An MCP server for Search Console on npm, listed in several MCP directories.
Stack
TypeScript and Node, Python, PHP and Laravel, Java and Spring Boot (WebFlux), React, Next.js, Vue, Flutter, React Native, Electron. PostgreSQL, MySQL, Redis, SQLite, D1. AWS, Cloudflare Workers, Docker, Nginx, Linux. GraphQL and REST. Payment gateways, in-app purchase receipt validation, social login, FCM.
What I am looking for
Remote contract work or a remote role, backend or full-stack, with written communication. Data pipelines, API integrations, LLM-backed tooling and "this thing must keep running unattended" work are what I enjoy most and what I am fastest at.
Reach me at globalmatchhub@gmail.com. Tell me what is broken or what you want built, and you will get a written plan back, not a meeting invite.
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