Hello, I'm
Sunho Hong
Senior Software Engineer · Product & Tech Leader
Senior software engineer and product-focused technologist with 19+ years of experience across enterprise systems, consumer platforms, collaborative tools, and digital healthcare. Strength in scalable backend design, workflow-driven product engineering, and end-to-end delivery across cross-functional teams.
Skills & Expertise
Core
Technologies
What I'm Building
Linglo
In DevelopmentFounder / Full-stack Engineer
Problem
Korean adult English learners often develop strong reading and listening skills through years of exam-focused education, but struggle significantly with real-world speaking.
Despite having extensive exposure to English, many learners find it difficult to produce natural responses in conversations, as their learning has been largely passive and memorization-driven.
Existing language learning apps such as Duolingo (over $1B annual revenue) and Speak (over $100M annual revenue), as well as popular Korean apps, focus heavily on vocabulary and short reactive expressions. While effective for beginners, these approaches are often insufficient for adult learners who need to develop practical conversational fluency.
Solution
Linglo is an AI-powered English speaking practice platform designed to help learners move from passive knowledge to active fluency.
It uses LLM-driven repetition learning, where users practice real-life conversational scenarios until expressions become natural and immediately usable in real interactions.
The product is built from the perspective of a real user — as someone who has personally experienced the gap between understanding English and being able to speak it fluently, Linglo focuses on solving this specific problem in a practical and scalable way.
Approach
Rather than relying entirely on LLM-generated content and grading (which can introduce inconsistency and quality issues), Linglo combines structured learning design with AI capabilities.
Content is curated and structured based on real English learning materials, and enhanced with LLM-powered on-demand dictionary and phrase engines.
The system is designed to ensure consistent learning quality while leveraging AI for flexibility and personalization. This approach is informed by prior experience building LLM-based products (including Alan Works, Memics, and AI-driven medical reporting systems), allowing for a more reliable and production-ready implementation.
Vision
Linglo begins with Korean adult learners, where the need for practical speaking-focused learning is particularly strong due to the structure of existing education systems.
Given the size of the Korean English education market and the proven demand for language learning products, there is significant opportunity to capture a meaningful segment with a more effective approach.
Over time, this learning model can be extended to similar cultural contexts and eventually to global English learners, positioning Linglo as a scalable platform for practical, conversation-focused language learning.
Experience
Senior Software Engineer
HemoAI Co., Ltd.
- Built an AI-based blood test reporting system with clinical-style reporting; adopted by GC Greenross (Korea's leading clinical lab).
- Developing Memics AI, an AI music creation app (in progress).
- Designed and maintained backend/web services for AI-driven healthcare and data analysis products.
Full-stack Developer
Enterprise multi-LLM SaaS platform built in collaboration with ESTsoft. Currently in early sales phase with 5 enterprise clients and ~1,000 active users.
Mobile App Lead / System Architect
AI music creation service where AI producers generate music tailored to user preferences. Built the entire mobile app and designed the system architecture.
Product Engineer / Senior Software Engineer
- Designed and developed a collaborative workspace platform connecting YouTubers and video editors.
- Implemented workflow-oriented web features for review, iteration, and role-based collaboration.
- Built the mobile app using React Native, handling both iOS and Android platforms.
Senior Software Engineer
Collaborative workspace connecting YouTubers and video editors. Workflow-oriented features for review, iteration, and role-based collaboration.
Co-founder / CTO
- Co-founded a startup addressing information asymmetry in the senior care market.
- Led end-to-end product development from prototyping to production.
Co-founder / Full-stack Developer
Designed and built the caregiver matching system with full-stack architecture. Now serving 280,000+ active users connecting caregivers with senior care facilities.
Head of Product / Head of Engineering
- Led product and engineering for Goodoc, a leading digital healthcare platform in Korea.
- Spearheaded complete app renewal and new feature launches including telemedicine and vaccine pass.
- Led a major system integration programme with cross-team coordination and legacy migration.
Goodoc Renewal
Project Lead
Full system renewal of Goodoc's 7+ year-old platform — hospital search, appointments, patient management, advertising, and product sales. Redesigned infrastructure end-to-end.
Goodoc Vaccine Pass
Project Lead / Developer
Designed and implemented a vaccine certification system during COVID-19, including verification workflows and integrations with partner venues.
Product Engineer / Product Owner
- Joined as the 10th team member; grew with the company as it became a unicorn (valued at 1T+ KRW).
- Developed core features for financial/business management services for small businesses.
- Built accounting, reporting, and tax-related functionality as a full-stack engineer.
- Featured by the World Economic Forum — weforum.org/organizations/korea-credit-data
Cashnote
Senior Software Engineer
Developed monthly ledger, review system, and other core features as a senior software engineer across both backend and frontend.
Senior Software Engineer / Product Owner
- Korea's Glassdoor — a leading company review and job search platform.
- Built and enhanced Ruby on Rails web services; introduced React to modernise the frontend.
- Led business-focused project tracks including resume management and recruitment systems.
Jobplanet Resume
Senior Software Engineer (Sole Developer)
Single-handedly designed and built the resume system — still in use today with minimal changes. Pioneered a practical, modern resume format in Korea, moving away from rigid traditional formats.
Head of Development
PlusMX
- Operated and scaled live game services for a large concurrent user base over 1.5 years.
Pro Baseball Dream Nine
1M+ DownloadsHead of Development (Backend)
Card-based mobile baseball game. Redesigned and fully rewrote the backend originally built in PHP page-based architecture (licensed from Konami). Led all server-side design, implementation, DB tuning, and live operations for 1.5+ years.
Software Engineer
- Developed consumer-facing social networking services.
- Participated in system rewrites and tech stack transitions.
Senior Software Engineer
- Built and operated Samsung MySingle — an internal enterprise portal at large scale.
- Delivered enterprise web systems serving thousands of internal users.
Side Projects
YouTube looper tool for musicians to practice with precise loop control, playback speed adjustment, and saved loop positions. Featured on Reddit's r/Guitar community.
Education
Sangmyung University
B.Sc. in Software Engineering
2001 — 2007
University of Waikato
ApplyingMaster of Information Technology
Seeking to strengthen academic foundations through graduate-level study, combining 19+ years of industry experience with rigorous academic research in software engineering.
Contact
I'm always open to discussing new opportunities, collaborations, or academic partnerships. Feel free to reach out.