Jaeyong Sung
jaeyong0201@gmail.com
About
Passionate about open-source and solving hard technical problems across the stack, from compilers to neural networks.
Work Experience
Cartesia
San Francisco, CA
Researcher
Jan. 2026 - now
- Research on real-time voice AI and State Space Models
Nari Labs
San Francisco, CA
CTO & Co-founder
Aug. 2025 - Dec. 2025
- Built 1.6B parameter TTS model in 3 months with zero traditional funding.
ROK Air Force HQ
South Korea
Sergeant, SWE
Oct. 2023 - Jul. 2025
- Lead SWE. Details restricted.
Samsung
Seoul, South Korea
Algorithm Coach
Jul. 2023 - Aug. 2023
- Coached algorithm training programs for university students
IBS, KASI, NIMS
Daejeon, South Korea
Rust Instructor
Jul. 2022 - Aug. 2022
- Taught Rust to researchers at Korean research institutes
Education
KAIST (Korea Advanced Institute of Science & Technology)
Daejeon, South Korea
B.S. Computer Science (on leave)
Mar. 2021 - Feb. 2027
Gyeonggi Science High School
Gyeonggi, South Korea
Computer Science
Mar. 2018 - Feb. 2021
Skills
Programming Languages
- Rust
- C/C++
- Python
- JavaScript
Machine Learning / AI
- Speech AI
- Optimization
Domains
- Systems
- ML Infra
- Research
Languages
- Korean (Native)
- English (Advanced)
Awards
Korea Olympiad in Informatics — Gold Medal (4th place)
- Gold Medal (4th place) in Korea Olympiad in Informatics
Jan. 2020
Samsung Collegiate Programming Cup — Joint 5th place
- Joint 5th place in Samsung Collegiate Programming Cup
Jan. 2021
Hyundai MOBIS Algorithm Competition — Joint 5th place
- Joint 5th place in Hyundai MOBIS Algorithm Competition
Jan. 2021
Union of Clubs Programming Contest — Joint 4th place
- Joint 4th place in Union of Clubs Programming Contest
Jan. 2023
Ministry of National Defense Startup Challenge — 2nd place (Minister’s Award)
- 2nd place (Minister’s Award) in Ministry of National Defense Startup Challenge
Jan. 2024
Korea Air Force AI Hackathon — Joint 3rd place
- Joint 3rd place in Korea Air Force AI Hackathon
Jan. 2024
Alliance Students’ Venture Forum — 1st place in Korea, National Representative
- 1st place in Korea, National Representative in Alliance Students’ Venture Forum
Jan. 2025
Projects
Dia
- Open-source TTS with zero-shot voice cloning and lifelike emotions.
- #1 on HuggingFace, 19K GitHub stars.
Relay Browser
- AI browser in Rust + Objective-C + JavaScript.
- Built solo in 3 weeks.
- Won Minister of National Defense Award.
Rust Clippy
- Graph-based static analysis lint detecting dead recursive arguments.
- Merged to official Rust toolchain.