- Migrated .Net and SQL Server based legacy web application to Node.js, MySQL and Angular based- Rebuilt high traffic pages with React based Server Side Rendering for SEO- Used Kubernetes to host the front-end systems built with different architectures which are Angular and React- Used Kubernetes to host the API servers, one is for frontend and another is for internal.- Rebuilt the admin panel with Next.js and TypeScript- Built a event tracking system with Amazon Kinesis Data Firehose and BigQuery

- Implemented the web version signup flow using Next.js- Re-architected the email template system using Sendgrid- Re-architected the event tracking system using BigQuery. Designed and implemented data ingestion from Amazon Kinesis Firehose to BigQuery. Planned and executed migration from the existing system.- Re-architected the existing feature flag system, designing and implementing a criteria feature that can return different flags based on mobile application versions- Introduced integration testing to the backend system built with Node.js and TypeScript, and set up CI/CD pipelines- Improved the architecture of the Android application. This included migrating to Jetpack Compose, introducing Room and Hilt, and adopting the MVVM pattern.- Implemented screenshot testing for the Android application and integrated it into the CI/CD pipeline

- Implemented iOS app for an asian dating service targeting US market (Swift)- Built a dating service for asian market (Ruby on Rails, React and GCP)- Built live streaming recording functionality (Go and Kubernetes)- Migrated the infrastructure to Ansible based

- Implemented Hashflag functionality, which allow you to embed specific emojis with specific hashtag, for Twitter Web (Scala) and iOS (Objective-C) and Android (Java)- Implemented Translation A/B testing functionality, which enable the translator to do A/B testing with some variation of translation, for their major platform such as Web, iOS and Android- Integrated Tweet translation functionality for Twitter iOS (Objective-C)- Integrated Japan specific News functionality for Twitter Android (Android)

- Built a social gift service (Ruby on Rails and MySQL)

- Integrate an ad network system which is acquired by the company to our system (Scala, PHP and Ruby on Rails)

- Worked on developing a social game platform (Ruby on Rails and MySQL)- Worked on a renewal for a publishing system of carsensor.net which is one of the most famous second hand car information magazine in Japan (Ruby on Rails and Oracle)