WonHee Jung


I started a software engineer career in 2000 after graduating the college with BS Computer Engineering. I had my first job at a startup company that focused on a search engine and a knowledge-management system. Since then, I worked on numerous enterprise solutions for three major S.Korea mobile careers. That includes SK Telecom, Olleh(KTF), and LG U+. I also worked on international customers like Telkom Flexi Indonesia for their prepaid voucher management system and dealer management system development. 

After joining Blizzard Entertainment in 2010, I have been working on game site CMS, game franchise blog and forum, search, Battle.net account management, purchase, and many other projects. My job in the current team is focusing on performance improvement, develop and maintain the e-commerce department's shared libraries, researching new tech, and oauth2 support.

 I enjoy learning new topics, not limited to software development boundaries. I joined the Master of Computer Science in Data Science program at the University of Illinois Urbana-Champaign to extend my understanding in data science and machine learning, and distributed/cloud computing area, and recently graduated in August 2020.



R, Kubernetes, GCP, Terraform, Machine Learning/Data Science, C++, Data Visualization(Tableau, D3), Data Cleaning and Curation, Scikit-learn, TensorFlow, OpenRefine


Spring-boot, AWS, C, Google Protobuf, Jenkins 2, Heroku, Maven, Python, Hibernate, MyBatis, Javascript, Oracle, Splunk


Java, Spring framework, OAuth2, Git, Docker, Unit testing, Agile/Scrum based development, project planning, writing design documentation.

Work Experience

Blizzard Entertainment

Senior Software Engineer, Sep 2014 ~ Present

Working on Battle.net platform, which provides pretty much everything you can see on Battle.net website, in-game client purchase, and behind-the-scene technologies that empower Battle.net.

- Initiating & researching solutions to replace current HashiCorp Vault based secret management (2020 ~ present)

- Migrating in-house RPC error response message builder to use new RPC error builder (2020 ~ present)

- Replacing the old authentication system to OAuth2 in Battlenet backend, including Blizzard API Gateway support, adding custom Google Protobuf definition and customized proto-maven-plugin to generate Java code, shared libraries to populate an authentication and propagating, and all the coordination between teams&departments and update all the relative libraries. ( 2017 ~ present )

- Implemented alerts for multiple metrics on in-house ELK solutions. (2018~2020) 

- Implemented Spring Security oauth2 async use case support under  various async job, thread pool, async caching load in Google Guava, etc. (2019) 

- Upgraded internal payment systems that talk with 3rd party to use TLS secure endpoint and all the follow-up through multiple teams in the Battlenet. (2018~2019) 

- Proposed and implemented a solution for oauth2 scope issue between inter-service calls. (2018)  

- Dockerized Battle.net's backend middleware. ( 2017 ) 

- Replaced heavy cross-region JDBC Oracle call between physical regions to lightweight WebSocket-based API( 2016 ) 

- In-game purchase feature for game teams and Battlenet. ( 2014 ~ 2015 ) 

Software Engineer, Mar 2011 ~ Sep 2014

- From April 2012, changed a team and worked at Battle.net team, focused on feature developing/maintaining middleware backend which provides game account creation, payment, etc (2012 ~ 2014)

- Worked as Web Software Engineer in web community team, focused on feature development and maintenance of CMS/community blog & forum search/etc. (2011 ~ 2012)

Blizzard Entertainment Korea

Senior Web Software Engineer, Jan 2010 ~ Feb 2011

- Focused on feature developments and system modifications for S.Korea specific requirement, e.g, account creation process required by Korea law, Korea local payment 3rd party interaction, and KR personal verification by IPIN, credit card, SSN, etc as individual contributor. Used Spring framework, Oracle, PL/SQL, Velocity, and necessary web frontend task. 

Uangel Corporation

Platform Development Team, Development manager, Jun 2003 ~ Jan 2010

- Delivered VMS(Voucher Management System) to PT.Telkom Flexi Indonesia. PT Telkom Flexi is the biggest CDMA mobile carrier in Indonesia and have more than 20 million subscribers. The client's business was prepaid-based and the needed voucher top-up & voucher dealer management system. Worked as main system design architect, software engineer, project develop lead, and also project manager, in charge of managing 4~5 Uangel employees, 5 outsourcing developers, 2 third party hardware vendor employee, and 2~3 PT Unagel Indonesia employees. The system was configured in both Jakarta and Surabaya to handle both regional requests and also sync the transaction record seamlessly. Also the system was configured for fault-tolerance for every component so that there is no single failure point. Used Spring framework, Oracle RAC clusters, PL/SQL, C++ for ISO-8583 PoS message processing, etc.
- Developed and delivered MMS (Multimedia Messaging Service) web service, gateway server, and billing systems to SK Telink in S.Korea. Took a software engineer and project develop lead role. 


Software Engineer, Mar 2002 ~ Feb 2003

- Developed LG Telecom's Location Based Service authentication gateway server for 3rd party and other mobile carriers in S.Korea. System includes control software for operation team, Microsoft COM+(ActiveX) for web UI, etc as software engineer and as project lead. 

- Developed LG Telecom Content Management System, mainly focused on project and task management part. It was similar to nowadays Atlassian Jira without bug tracking feature. Used ASP, Javascript, and HTML, and Microsoft SQL Server.

- Developed KTF(current KT) Qualcomm BREW mobile application Couple Forecasting and Fortuneteller, mainly as backend service developer including raw TCP-socket based communication format design and supported Qualcomm Brew client development and QA. Used C++ on FreeBSD for server, Qualcomm Brew SDK, and Berkeley DB. 


Software Developer, Jan 2000 ~ Feb 2002

Worked on document indexer, web search engine interface implementation, and web/intranet documentation crawler for the company's search engine solution called MyFinder as software developer. Also worked on a few MyFinder based customizing projects for Sony Korea customer center, GS Caltex, Republic of Korea Navy, etc. Used HTML, Javascript, Servlet, JSP, Oracle, and Borland C++ Builder for Microsoft Office docs crawling and indexing.


Georgia Institute of Technology

Master's degree in Computer Science, 2021 ~ 2025(planning)

Got an admission and starting a Georgia Tech's OMSCS program in Spring 2021 to learn more towards traditional CS fields.


University of Illinois at Urbana-Champaign

Master's degree in Computer Science, 2018 ~ 2020

Text retrieval/mining, cloud computing applications/network, data visualization, machine learning, data cleaning, data curation, cloud computing, networking, and cloud capstone project. Phi Kappa Phi Honor Society member. Graduated in August 2020 with GPA 3.95/4.0

Worked on a few projects such as 

Airline On-Time Statistics analysis for 1988~2008 data using AWS solutions, e.g., AWS EMR, with HiveQL, DynamoDB,  S3, Glue, Athena, Kafka, etc. (Cloud Computing Capstone)

- DetoxBot, DetoxBot2(cloud version deployed in GCP's GKE)

- Data Visualization for World Bank data with Tableau, Narrative Data Visualization for World Bank data with D3 


Dong-A University

B.S. in Computer Engineering, 1996 ~ 2000

Computer engineering major. 

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