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Sangyoon Lee, full-stack developer, 13 years (small teams, one person from spec to production to the pager). Everything below is public, so you can check it instead of taking my word:
- SearchLink, a live SaaS I built and run alone (Cloudflare Workers + D1, OAuth, billing, MCP server): https://searchlink.namubase.com - Marketplace extensions that passed store review: VS Code https://marketplace.visualstudio.com/items?itemName=sellerki..., JetBrains https://plugins.jetbrains.com/plugin/34045, WordPress.org https://wordpress.org/plugins/podsync-for-woocommerce/, Apify https://apify.com/sellerkit/google-trends-scraper. Also an Atlassian Marketplace Jira app (vendor: Global Match Hub). - Write-ups of what broke and how I fixed it: https://reviewgated.hashnode.dev and https://dev.to/globalmatchhub_b7ad9cba
Passing a marketplace review means finding the bugs before submission, so QA and verification are how I work: I find what breaks before your users do. In 13 years I have never missed a KPI I was given. Whatever number you measure me on, I will hit it, and I will report progress against it in writing every week.
Open to: a monthly salary-style retainer (part-time or full-time), a 12-month contract, or fixed-price projects (web/API development, QA and test automation, Ansible/DevOps, integrations). Also happy to be the quiet backend partner behind a small team. Available now.
How I keep it low-risk for you: I work fully in writing (email/Slack/Notion, async), no calls, and everything is documented. Your code lives in a repo you own from the first commit, with handover notes. Instead of an interview, the first small task is free. We agree on the scope in writing first (up to about 10 hours of work), and I deliver within a week with a short written update every day. If you like the result, we continue on a paid basis. If not, you've lost nothing. One free task per company.
Sangyoon Lee, full-stack developer, 13 years (small teams, one person from spec to production to the pager). Everything below is public, so you can check it instead of taking my word:
- SearchLink, a live SaaS I built and run alone (Cloudflare Workers + D1, OAuth, billing, MCP server): https://searchlink.namubase.com - Marketplace extensions that passed store review: VS Code https://marketplace.visualstudio.com/items?itemName=sellerki..., JetBrains https://plugins.jetbrains.com/plugin/34045, WordPress.org https://wordpress.org/plugins/podsync-for-woocommerce/, Apify https://apify.com/sellerkit/google-trends-scraper. Also an Atlassian Marketplace Jira app (vendor: Global Match Hub). - Longer write-up of past paid work (kids news app on Flutter + Spring Boot WebFlux, unmanned study cafe system with payments and door control, healthcare platform on Laravel + React): https://dev.to/globalmatchhub_b7ad9cba/i-ship-backends-alone...
Passing a marketplace review means finding the bugs before submission, so QA and verification are how I work: I find what breaks before your users do.
Open to: a monthly salary-style retainer (part-time or full-time), a 12-month contract, or fixed-price projects (web/API development, QA and test automation, Ansible/DevOps, integrations). Also happy to be the quiet backend partner behind a small team. Available now.
How I keep it low-risk for you: I work fully in writing (email/Slack/Notion, async), no calls, and everything is documented. Your code lives in a repo you own from the first commit, with handover notes. I am happy to do a small paid first task so you can judge the quality before committing to a month or a year.
Location: Seoul, South Korea
Remote: Yes (remote only)
Willing to relocate: No
Available: February 2027
Technologies: Flutter, Spring Boot/WebFlux, Laravel, React, Vue,
TypeScript, Node.js, GraphQL, MySQL, Redis, AWS, Cloudflare Workers,
Docker, Electron
Résumé/CV: https://sangyun-lee.sellerkit.workers.dev
Email: [email protected]
I am looking for part-time, ongoing work rather than one full-time seat: about 20 hours a week per company, and I can hold two at once. I am free from February 2027, and happy to talk now and line up a start date.
Most recently I shipped a kids news app in Flutter for a Dong-A Ilbo subsidiary, then rebuilt its backend on Spring Boot WebFlux and moved the app across without an app-side rewrite, because the API boundary was GraphQL from the start. Before that: an unattended study-cafe system (Electron kiosk, recurring card billing, door controllers), a healthcare platform on Laravel/React serving clinics, patients and operators, and a Flutter/Firebase chat app with push and in-app purchases.
Part-time works with me because nothing waits on a handoff. I own the app, the API and the server, so a feature goes from spec to release without three people syncing. Payment integrations and "the app runs but the backend needs replacing" are both familiar ground.
I am in KST (UTC+9) and can hold a few hours of European or US-morning overlap.