Sejin Lee

About

I enjoy mobile applications based on React Native, so I don’t feel building apps is working but having fun. I can understand the whole picture of projects because of my experiences in running my own startup. I worked as a back-end java programmer. However, now I switched work area to a React Native developer. I have experience using various modules and like getting to know how the best ways to make use of them. In addition, I have experience solving performance issues. I think performance is the most important part of React Native, that’s why I am persistent in enhancing all of my apps performances.

Experience

• softgarden (Berlin, Germany)
  • Angular Application Developer
    Mar 2024 - Present · 2 yrs 4 mos

    Angular v17~21, SOLID and DRY architecture, Angular migration, Signals, Standalone, NgRx, Optimizing rendering, i18n, Text editor migration(TinyMCE -> Tiptap), data sanitizing, meet WCAG2 by Lighthouse), Jasmine/Karma, AI-driven using instructions, agents, skills, Angular+Redux+postman Dev tool, amplitude analytics feature flag, frontend guild activity

  • Mobile Application Developer
    Apr 2018 - Feb 2024 · 5 yrs 11 mos

    • Working with React Native ( Typescript, Jest, Zustand/Redux, Apollo grpahql, Bridged en/decryption module, Firebase analytics+FCM, date+file Pickers ) > 7y • Working with Flutter ( Riverpod, Freezed, Mockito, Cucumber for the integration test ) = 1y • Implementing end points on (graphql) server > 5y • Analyzing request and response from endpoints by using chrome debugging tool and postman

• Full Stack Engineer at KB데이타시스템 (KB Data Systems)
  Jul 2014 - Jun 2017 · 3 yrs

  • ​Managed and developed overseas banking system for 11 nations in the department of budgeting and accounting • ​Developed and upgraded 38 online and batch programs for international branches • ​Made over 150 SQL queries to generate appropriate reports for bank tellers and managers

• Web Developer Task force team at POSCO ICT
  Jun 2013 - Oct 2013 · 5 mos

  • ​Took part in task force project for new overseas HR groupware web application systems as an intern • ​Developed 34 web pages including data visualization for salary management and well-being of staff

• Security Application Developer at Penta Security Systems Inc.
  Jul 2012 - Oct 2012 · 4 mos

  • ​Measured running time of encrypting / decrypting data in MSsql server and successfully identified the 1.2 min delay in Common Runtime Language • ​Developed MSsql procedure to validate if encrypted / decrypted data is normal.

• Co-Founder at Startup
  Nov 2011 - May 2012 · 7 mos

  • ​Got patent with disposable Qrcode and adapt this to online education system • ​Got outsourcing web application projects such as PMS, AquaDesign and DotMedia • ​Developed Android Native Applications such as BlueBird and Coincidence Letter