Hyeonseop Lee

I’m a software engineer with 6+ years of experience in areas including ML engineering, data engineering, and backend software engineering. I am interested in delivering real-world business value through a data-driven software system.

☎️ Contact information

πŸ“§ hyeonseop@ls-al.me

πŸ”—Β https://www.linkedin.com/in/hyeonseop/

πŸ‘¨πŸ»β€πŸ’» Work experience

Machine Learning Engineer

Moloco, Seoul, Korea - (Sep 2022 - Present)

Technical Lead

Grinder, Daejeon, Korea – (Sep 2020 - Aug 2022)

Designed and developed B2C commerce platform capable of 3rd party sales.

Set up data pipelines to collect and analyze user behavior logs.

Led machine learning projects to strengthen content-based commerce.

Machine Learning Engineer

PUBG, Seoul, Korea – (Jul 2018 - Aug 2020)

Designed and developed real-time A/B testing platform for global services with 1M+ CCU.

Improved service sales by establishing real-time recommendation system using Bayesian Inference and MAB.

Data Engineer

Hyperconnect, Seoul, Korea – (Sep 2016 - Jun 2018)

Developed data pipelines that handles user behavior logs for large-scale global services.

Built a real-time push transfer pipeline and conducted experiments on push message personalization.

Software Engineering Intern

Google, Mountain View, CA, USA – (Jan 2016 - Jul 2016)

Implemented network congestion control mechanisms for data center SDN.

πŸ›  Skills

πŸ’» Tech Stacks

Big data and data pipelines frameworks

Spark, Flink, BigQuery, Athena, ElasticSearch, HBase, Airflow

Containers and cloud-based infrastructures

Docker, Kubernetes, Prometheus, Helm, AWS, GCP, Terraform

Backend software engineering

Python, Golang, Java, Kotlin, Django, Spring, gRPC, OpenAPI


Jira, Confluence, Notion, Git flow, GitHub PR review process

πŸ—£ Languages


Native speaker


Upper-intermediate speaker

πŸ† Honors and Talks

Talk β€œλ¨Έμ‹ λŸ¬λ‹λ„ A/B ν…ŒμŠ€νŠΈλΆ€ν„°β€ (A/B Testing for Machine Learning)

Krafton Developer Conference 2019

Talk β€œκ·ΈμΉ˜λ§Œ μ΄λ ‡κ²Œ ν•˜μ§€ μ•ŠμœΌλ©΄ A/B ν…ŒμŠ€νŠΈ μ‹œμΌœμ£Όμ§€ μ•ŠλŠ”κ±Έβ€ (Things had to be done for A/B Test)

Nexon Developer Conference 2019

Talk β€œWhen seasonality meets Bayesian: Decomposing seasonalities in Stan”

StanCon 2019

ACM-ICPC World Finalist

ACM-ICPC World Finals 2015, 15th place (KAIST)

DEF CON CTF Final Participant

DEF CON 24 CTF (2016), 5th place (KaisHack GoN)

DEF CON 22 CTF (2014), 10th place (KAIST GoN)

πŸ“š Education

Bachelor's Degree in Computer Science

KAIST School of Computing, Mar 2013 - Aug 2021