Mr. Latte Story

About

This English page is a machine translation of the Korean original, so some wording may read a little off.

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 - InverseOne tests 118 trading rules across 60 Korean large caps after costs. Inspect each surviving rule on a stock, check its current conditions, edit a strategy and run automated paper trading on your own server. Historical results do not imply future returns.
  • Reputo - A five-language career guide that turns a vague job title into a deep report split across fit, roadmap, study, reality, competencies and resources. Saving a prep plan, per-item notes, career matching and Reality Session requests come with a Reputo Plus subscription. Reports, job comparison, hiring requirements and roadmaps are free for anyone to read.
  • StartupXO - StartupXO is a multilingual community for discussing how technology and products change work and daily life. Read links, clear summaries and editorial comments, then share questions, projects and job posts. Korean, English, Japanese, Spanish and Arabic share votes and discussions on the same posts.
  • Typdit - A web rich-text editor you can start writing in right away. Markdown shortcuts, slash commands, writing modes, clean paste from Notion and Word, autosave and document templates, plus the same editor droppable into any site with a single script tag.
  • DeepThought - Read annotated maps, fork them into your own drafts, and publish them as links. Basic editing and sharing are free; file exports and map review come with Plus.
  • BootSignal - A drop-in tool workshop that keeps adding the small tools any website needs. One subscription, $20 a month or $200 a year, turns on every widget for one domain. Free visitor tools (QR generator, D-day calculator, JSON tidy) need no sign-up, and embed widgets (countdown, announcement bar, comments, ratings, feedback) go on your own site in a single line.
  • Out of Service - Out of Service monitors major Korean services and personal URLs. Check response times, incident history, official notices and user reports, receive outage and recovery alerts, and share status widgets. Available in Korean, English and Japanese.
  • DoYouBox - A play portal of personality tests, ideal-type tournaments, mini games and draws to enjoy lightly and share with friends. Friends react to your result, take the same test to compare, or guess your answers, so one share turns into a conversation. In Korean, English, Japanese, and Simplified and Traditional Chinese.

View all services

See my offer structure in Work With Me.

Projects

Recent highlighted projects.

See Projects for the full list.

Research & Patents

Papers

Book

Patents

Credentials

National Certifications

  • Engineer Information Processing
  • Linux Master Level 1
  • Computer Literacy Level 1
  • Office Automation Engineer
  • Information Device Operator
  • Web Design Technician
  • Word Processor Level 1
  • E-Commerce Manager Level 2
  • Social Worker Level 2

Online Certifications

  • Blockchain Specialization, Coursera (University at Buffalo)
  • Blockchain Platforms, Coursera
  • Decentralized Applications (Dapps), Coursera
  • Smart Contracts, Coursera
  • Blockchain Basics, Coursera
  • RPA Developer Advanced Certification, UiPath
  • RPA Developer Foundation, UiPath
  • RPA Developer - SAP Automation Training, UiPath
  • UiPath Security Training
  • UiPath Licensing Training
  • Advanced Google Analytics, Google
  • Google Analytics for Beginners, Google
  • Entrepreneurship Foundations, LinkedIn
  • Chief Technology Officer Career Guide, LinkedIn
  • Programming Foundations: Fuzzy Logic, LinkedIn
  • Working Remotely, LinkedIn
  • ExO Foundations, OpenExO
  • MCAS Master, Microsoft
  • GTQ Level 1
  • Ubiquitous Knowledge Certification
  • Internet Information Manager Expert

Support

If my content or open source work has been helpful, consider supporting me.

Looking for a product partner or a lecture? Founders, teams, businesses: from problem framing to launch, plus development lectures shaped for teams and schools.
Work With Me Teaching Get in touch →