Changhwan Choi Email & Phone Number

Seoul, Kr

As an early stage starting member of the team, I design and develop the entire DeFi system (from the smart contracts to the mobile application) that works across multiple chains and utilizes various crypto-assets. Also designed the finance model for loan and savings.Working with a remote team, I learned how to communicate with people of different timezones.- Smart Contract-- Solidity (Ethereum)-- Have tested nearly 100% test cases, and perform automated tests and various brute force tests to ensure that smart contracts are reliable.- Mobile Application-- Expo (React Native)-- The main goal was to provide the best user experience for savings and loans using cryptocurrency.- Backend-- TypeScript-- Interacts with Blockchain(Ethereum, Basechain) to monitor, cache and normalize the Smart contract activities.

Gangnam-Gu, Seoul, Korea

Geumcheon-Gu, Seoul, Korea

While I was managing the software development team, I was also responsible for building mobile applications (iOS / Android) and websites (uniquely accessible for the visually impaired). I have also collaborated with developers from various nationalities, and as a result, Dot Incorporation has been able to create reliable and efficient multilingual Braille translation engines successfully. - iOS/Android Application Development -- swift / java, kotlin -- The primary target for a mobile application is maintaining accessibility for the visually impaired. Also, deliver the same user experience in both mobile OS in a unique design identity.- Web backend / frontend -- python(Django, celery, rest) / MariaDB, Postgres, SQLite / html5, jquery / Web Accessibility -- Tried to offer a quick way to access key information about Dot Incorporation's products while maintaining accessibility for the visually impaired.- Braille Translation Engine -- std C99, std cpp11 code review (Keil/Arm) -- Managed developers of various nationalities and reviewed and tested Braille transition engine code.

대한민국 서울 강남구

Designed and developed blind-auction based market system for car dealers who wants to buy used cars at a lower price.I was responsible for all software from web backend to frontend (website and mobile application). Also, I learned to inspire and motivate the junior-level (post-college) developer while leading small dev-team.- Backend-- Python (Django based REST API) / MariaDB-- The main goal of the system was reliability - not real-timeliness - by design. So the system tracks and records every user actions to provide transparency - users can see these records after each auction.- Web Frontend-- jQuery / Web Standard-- Frontend was targeted for desktop use only and used basic jQuery based web-app feature, so users don't need to refresh after each bid.- Mobile Application-- Java (Android)-- Focused to provide easy-to-use UI/UX to users - especially multiple-bid feature.

Seoul, Korea

- CentOS, Nginx, PHP, MySQL, Node.js, Memcached, Webstandard

Seoul, Korea

- 소셜 댓글 서비스 개발- CentOS, Apache, MySQL, PHP, Memcached- 대용량 서비스 구축