Dave Hyungmok Lee, Python Developer in Seoul, South Korea
Dave Hyungmok Lee

Python Developer in Seoul, South Korea

Member since September 4, 2013
Dave Hyungmok is a self-motivated and goal-oriented professional committed to pursuing a long-term career in computer engineering. He created 2+ fully functional apps for Android devices, one of which has ranked #1 in the Korean Android market. Dave Hyungmok is known for writing efficient, maintainable, and reusable code and has strong development and problem-solving skills.
Dave is now available for hire


  • Calm Island
    Java, Go, Python, React, JavaScript, Shell Script, Git, Jenkins, AWS
  • Kidaptive
    Java, Python, Kafka, Zookeeper, HDFS, Oozie, Git, Jenkins, PostgreSQL...
  • Ziontech Korea
    Java, Android, JavaScript, Kafka, CAS, GitHub, Jenkins, Zookeeper, Docker...



Seoul, South Korea



Preferred Environment

Mac OS X, Linux, IntelliJ, Eclipse, Sublime Text

The most amazing...

...thing I've successfully launched is a seller application for eBay, enabling users to see how garments look on an avatar prior to purchase.


  • Tech Lead

    2018 - 2020
    Calm Island
    • Led tech initiatives on the adaptive learning platform.
    • Led multiple projects such as mobile apps and data pipeline project simultaneously, targeting many countries such as China, Sri Lanka, and Vietnam.
    • Managed 15 back- and front-end engineers as tech lead.
    • Designed and led a big data platform targeting customers in many countries.
    Technologies: Java, Go, Python, React, JavaScript, Shell Script, Git, Jenkins, AWS
  • Tech Lead

    2018 - 2018
    • Led tech initiatives on the big data/machine learning platform ingesting 8 million events daily.
    • Supported multiple large companies using the big data platform in Korea.
    • Communicated between software engineers working at HQ and Korean customers.
    • Designed and coded APIs for customers in Korea and reduced development cost to 50%.
    Technologies: Java, Python, Kafka, Zookeeper, HDFS, Oozie, Git, Jenkins, PostgreSQL, Spring Framework, AWS, Hadoop, HBase, Spark, Hive
  • Senior Software Engineer

    2014 - 2017
    Ziontech Korea
    • Provided a solution to the challenge of the same UI as the existing heavy traffic iPhone app by designing and developing an Android application as lead.
    • Enabled messaging between components throughout the entire architecture by developing a message producing broker library with Kafka.
    • Provided a solution to SSO development needs by customizing an open source software CAS.
    • Reduced costs for back-end API development by 50% by refactoring an open source project eSCIMo, and debugged existing bugs earlier than scheduled.
    • Managed, assigned, and communicated programming tasks to teams of engineers in US, Korea, and India branches in a multi-lingual environment.
    Technologies: Java, Android, JavaScript, Kafka, CAS, GitHub, Jenkins, Zookeeper, Docker, eSCIMo, HSQLDB, SQL, JPA, JAX-RS, Backbone.js, CSS3, HTML5
  • PHP Developer

    2015 - 2015
    Adam Fordham Consulting (via Toptal)
    • Created website administrator modules using PHP, MySQL, and JavaScript.
    • Created front-end modules using JavaScript, jQuery, and Bootstrap.
    • Improved the performance of SQL and performed query optimizations.
    • Created a back-end payment module using PHP and CakePHP.
    • Improved the existing payment modules.
    Technologies: PHP, JavaScript, MySQL, CakePHP, jQuery, Bootstrap
  • Project Manager

    2013 - 2014
    ESES Global, Inc.
    • Designed and implemented an Android app providing guesthouse information.
    • Helped the app succeed as the number one app in the new free app section of Google Play Store.
    • Acquired +30,000 users in three months after launch with Facebook marketing.
    • Designed and implemented a search engine website providing job information for expatriates living in South Korea.
    • Acquired dispersed job information from Korea to give job seekers access to tons of job information with one search.
    Technologies: Android, LAMP, Yii, MongoDB
  • Java Developer

    2012 - 2012
    Samsung SDS (Contract)
    • Implemented SAP EP modules reflecting company-wide requirements of Samsung.
    • Designed front-end web pages for the responsive web requirements.
    • Enabled functionality on all other modern browsers, unlike the previous version which had only been available on IE.
    Technologies: Java, HTML5, SAP EP, Oracle
  • Senior Software Engineer

    2010 - 2011
    Outspark, Inc.
    • Increased work efficiency of PM and GM by developing a new CMS for web content management.
    • Improved front-end rendering performance by 30% by deploying a new client side platform for all game websites.
    • Improved back-end performance by creating a replacement of the existing server side platform.
    Technologies: PHP, JavaScript, jQuery, YUI, CodeIgniter, MySQL
  • Team Leader

    2008 - 2010
    G&G Commerce
    • Designed, developed, and successfully launched an innovative web avatar application on Ebay.com, which displays cyber garments. Users could search for items on the website by mapping cyber garments on an avatar using the application, and the company could get paid as an Ebay affiliate through this application because this application advertised Ebay sellers' items as a search result. This application enabled sellers to get profits on the net by putting this application into their websites and blogs reflecting customers' needs.
    Technologies: C, PHP, JavaScript, YUI, MySQL
  • Front-end Engineer

    2007 - 2008
    Yahoo Korea
    • Developed various Yahoo Korea portal web pages.
    • Designed and implemented games using JavaScript.
    • Constructed an intuitive game interface for the Korean market, which resulted in a positive user experience and high user engagement.
    Technologies: PHP, JavaScript, YUI


  • EdTech Kidaptive ALP (Development)

    Kidaptive's Adaptive Learning Platform (ALP) has AI-based algorithms that empower educational companies to use the data they collect to increase learner engagement and improve outcomes. I worked on the ALP as tech lead using a tech stack including Java, Hadoop ecosystems, and Python.

  • Wavity Cloud SaaS Application (Development)

    Enterprise cloud platform with reusable cloud applications that enables rapid development of new applications on the cloud, especially business-specific applications that leverage communications and collaboration.

    API-driven Cloud Services (ACS) – An abstraction layer for integration with classes of cloud applications

    Identity Cloud Services (ICS) – A centralized identity service to enable SSO

    Mobile Cloud Services (MCS) – to deliver push notifications,
    real-time analytics, and reporting for visibility

    I worked on SSO and the REST API as well as the Android mobile app.

  • Wavity OneTeam Android App (Development)

    OneTeam is a companion mobile app that can be used with the Wavity cloud platform and applications.

    Simple yet powerful tools in OneTeam enable you to create ad-hoc teams where individuals from within your company as well as outside your company come together to get work done.

    Key Features:
    • Perform all end user and administrator functions on the mobile app
    • Communicate, collaborate, and use business applications to get work done
    • Receive push notifications – be informed or take actions based on notifications
    • Access a centralized view of data relevant to you - as defined by you

    You must be a user/customer of Wavity’s web-based service to use the mobile app.

    For more information, please visit https://wavity.com

  • Pentui Android App (Development)

    An Android app which provides pension information for South Korea. I designed and implemented the app and negotiated deals and terms with KTCS for a business development based on the product. The app has been ranked as the #1 app in the new free app section of the Google Play store and in the Travel & Local category.

  • KoreaJob4Expats (Development)

    A website focused on providing job information for expatriates in Korea. Since 2014, KoreaJob4expats has given job seekers free access to millions of jobs from hundreds of company websites and job boards.

  • React Test-driven Development: From User Stories to Production (Publication)
    Employing a test-driven development (TDD) approach in React projects tends to be straightforward, especially with the aid of Jest and Enzyme. However, there are a few things to look out for. In this article, Toptal JavaScript Developer Dave Hyungmok Lee demonstrates his React TDD process, from epics and user stories to development and production.


  • Languages

    PHP, SQL, JavaScript, Python, Java, GraphQL
  • Frameworks

    Bootstrap, JPA, AngularJS, Django, Jersey, React Native, Django REST Framework
  • Libraries/APIs

    REST API, jQuery, React, Node.js
  • Tools

    IntelliJ, PyCharm, Eclipse IDE, Sublime Text 2
  • Platforms

    Android, Linux, Oracle, Ubuntu Linux, Docker, Kubernetes, AWS Lambda
  • Storage

    JSON, MySQL, MongoDB, AWS DynamoDB, AWS S3, AWS RDS
  • Other

    Unix Shell Scripting, AWS
  • Paradigms

    Test-driven Development (TDD), Unit Testing, REST


  • Master of Engineering degree in Software Engineering
    2011 - 2013
    Sogang University - Seoul, Korea
  • Bachelor of Engineering degree in Computer Engineering
    2007 - 2010
    Korea Polytechnic University - Gyeonggi, Korea


  • Essential Cloud Infrastructure: Core Services
  • Elastic Cloud Infrastructure: Scaling and Automation
  • Elastic Cloud Infrastructure: Containers and Services
  • Google Cloud Platform Fundamentals: Core Infrastructure
  • Essential Cloud Infrastructure: Foundation

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