About

I am a freelance software development expert based in Seoul, South Korea. Founders, teams, and businesses can hire me for product work. The identity I want this site to express is not just “full-stack engineer,” but someone who works across planning, development, and launch. I do not stop at implementing requested features. I work through why the product should exist, which user flow matters most, where the MVP boundary should be, and how that plan becomes a real shipped service.

Since 2002, the technology landscape has changed constantly, and I have moved with it: from Windows desktop software to mobile apps, from monoliths to service-oriented systems, from on-premise environments to the cloud. Over time, that reinforced a simple lesson: the technology matters, but the product structure, user flow, and operating model matter just as much. More recently, that has also meant working with generative AI and automation in practical ways across product features, internal operations, and development productivity.

Having studied both Computer Science and Business Administration, I can move comfortably between technical conversations and business ones. What I do best is run alongside you through the process of turning an idea into a working product. If there is something you have been wanting to build, reach out — let’s make it happen together.

How I Work

Reframe the problem first. Before breaking down features, align on the real user problem and the conversion goal.
Draw a clear MVP boundary. Decide what must be in v1 and what should be intentionally deferred.
Focus on user flow. A product becomes easier to build when the decision path is already clear.
Use AI deliberately. Not because it is fashionable, but when it improves real user value or operating leverage.
Think past launch. Operations, repeat usage, and learning loops are part of the product.

Experience

Nov 2020 - Present: Freelance

Partner with clients across multiple domains while owning problem definition, structure, implementation, and delivery. In parallel, I keep building and operating my own products so my product thinking is shaped by real launch and operating experience, not theory alone.

Aug 2018 - Oct 2020: PuzzleVentures (Director of Engineering)

Drove technical direction, architecture, and execution processes while taking the product from early concept to launch. After launch, focused on performance and operational stability so the service could keep running as a durable product.

Oct 2016 - Jul 2018: Freelance

Went independent after 14 years in companies, and expanded my experience across fintech, commerce, healthcare, and other domains where product and engineering execution had to move together.

Aug 2015 - Dec 2016: Eazler (Executive & Engineer)

Worked across operations and product building inside a business messaging startup. That environment made the connection between product decisions and business outcomes very concrete.

Feb 2003 - Jun 2015: ESTsoft (Lead Programmer)

Spent more than 12 years building large-scale products used by tens of millions of people, leading teams and learning how to ship reliably at scale.

Jan 2002 - Feb 2003: Comcast Korea (Developer)

Started my career by building internet broadcasting solutions and Windows applications.

Education

2019 - 2020: B.S. in Social Welfare (Self-Education Examination)
2012 - 2015: M.A. in Business Administration (MBA), Korea National Open University
2009 - 2011: M.S. in Computer Science, Chung-Ang University
1999 - 2008: B.S. in Computer Software, Gachon University

Services

Products I personally planned, designed, and operate:

InverseOne - Quant-driven contrarian intelligence platform that surfaces oversold rebound opportunities across Korea, US, Japan, and crypto
StartupXO - Human-curated talent matching platform that quickly connects startups and AI teams with pre-screened freelance specialists
DeepThought - Zero-install browser mind map tool that turns scattered ideas into clear visual structure in seconds
The Weple - Mood-based social lounge for short check-ins, low-pressure matching, and conversations that naturally expire

View all services

You can also browse public in-progress concepts in Ideas Lab and see my offer structure in Work With Me.