Hello! I'm Hyeongchan from Korea. I enjoy programming, working out, and bouldering.

• Service many machine learning products in various domains, Audio & Speech, Vision, NLP, Recommendation Systems, Tabular, and LLM applications in many startups.
• Kaggle 2x Expert. the highest competition rank is top 0.1%.
• Here's my C.V. Feel free to contact me at the email kozistr@gmail.com :)

previously...

• 2023 - 2024 : Joined Sionic.AI. Built enterprise-grade LLM applications.
• 2021 - 2023 : Joined Viva Republica (Toss). Developed many products like BNPL, CSS, OCR, NPS, CDP, and in-house products.
• 2020 - 2021 : Joined Watcha. Developed Watcha recommendation system, and contributed to other products like WatchaPedia, in-house applications.
• 2019 - 2020 : Joined Rainist (Banksalad). Developed a transaction classifier service to analyze the categories with low latency, high accuracy, and in real-time.
• 2019 : Joined VoyagerX. Developed a speaker diarization product that automatically recognizes the contents of the meeting.
• - 2019 : offensive security stuffs. Mainly researched and studied Linux kernel exploitation and reverse engineering.

Current Interests

• Kaggle Challenges
• Building something in Rust
• Bouldering

📊 this week i spent my time on:

Profile Views

Lines of code

I'm a Night 🦉

🌞 Morning 967 commits ██░░░░░░░░░░░░░░░░░░░░░░░ 06.40 % 
🌆 Daytime 6053 commits ██████████░░░░░░░░░░░░░░░ 40.08 % 
🌃 Evening 5530 commits █████████░░░░░░░░░░░░░░░░ 36.62 % 
🌙 Night 2552 commits ████░░░░░░░░░░░░░░░░░░░░░ 16.90 % 

Last Updated on 11/02/2026 15:57:12 UTC

📈 my github stats

kozistr