Hyunseok Joo
데이터 엔지니어 at ARPI
Seoul, South Korea
Summary
Hyunseok Joo is a data engineer based in Seoul with eight years of experience designing and operationalizing high-performance data pipelines and migration tools for healthcare and enterprise customers. He has driven measurable improvements—95% reduction in DB migration time, 40% faster API responses, and major cost savings in cloud spend—by applying DDD, ETL abstraction, and performance tuning. Comfortable across the stack, he has built CDC architectures with Debezium/Confluent/Databricks, containerized deployments for rapid hospital onboarding, and earlier worked on LIS systems in C#/PLSQL. An active contributor to open-source projects like the Hustoj online judge (back-end and UI integration), he combines practical engineering with a collaborative, knowledge-sharing mindset. Notably, his GitHub bio reflects a human-centered ethos—engineering “not for nationalism but for the earth and humanity”—that informs his focus on impactful, reliable data systems.
7 years of coding experience
2 years of employment as a software developer
Github Skills (10)
php10
web-development10
online-algorithms10
mysql9
templater8
template-engine8
ui-design7
interface-design7
user-interface7
css6
Programming languages (6)
Github contributions (5)
zhblue/hustoj
Jun 2018 - Aug 2022
Popular Open Source Online Judge based on PHP/C++/MySQL/Linux for ACM/ICPC and NOIP training, with easy installation. 开源OJ系统
Role in this project:
Back-end Developer
Back-end DeveloperContributions:116 commits, 9 PRs, 17 comments in 4 years 2 months
Contributions summary:Hyunseok primarily contributed to the back-end functionality of the online judge system, modifying PHP files related to user interfaces, administration menus, and contest management. Their changes included alterations to page layouts, such as in the user and news lists, and they introduced the ability to reset passwords via the admin menu. The user also modified front-end templates, adjusting the structure and appearance of various pages to integrate better with the design of the Hustoj project.
acmcppicpcmysqlonline-judge
melongist-zz/CSL
Sep 2020 - Oct 2021
For CSL Computer Science teachers at South Korea. Fast & Easy installation scripts for CMS, DOMjudge, HUSTOJ ...
Contributions:959 commits in 1 year 1 month
cmsscienceinstallationsouthsouth-korea
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