Java Developer

Designed and launched Nike shoes notification system in Japan region, which notifies the subscribed users when their interested shoes became in stock. After launch this application attracted ~5k DAU, almost 3x expansion of the user base. Designed and launched the POI (place of interest) system in Singapore region, which includes poi tagging workflow and poi landing page, enabling the users to search places and operation/product team to promote campaigns/events around places, increasing the user retention rate by 4% on weekly basis.

Implemented a timer-based card borrowing incentive, allowing players to borrow time-constraint cards into their card decks. Implemented a user inbox system, where if a user watched card become eligible to borrow, users can see a message in their inbox.

Developed and launched ControlPlane (the services manage all clusters lifecycle) features such as allowing running DAG on clusters, auto scaling nodes based on certain metrics, auto replacement of unhealthy nodes, allowing running tasks in parallel etc. Developed InstanceController (the daemon service run on each cluster) features, identified and fixed various multi-thread issues like deadlock, threads blocking each other, single thread stuck etc. which leads to service unavailable. Implemented a one-click workflow to generate regionalized credential and automation scripts to accelerate building EMR services in new AWS regions, reducing build time from 3 weeks to 1 week.

Designed and launched a differential download service for a package delivery app so that when a user requests to upgrade the app, service returns a patch binary apk instead of a full binary apk and the client side will apply the patch onto the old version apk, reducing the download size from 80MB to 17MB. Implemented the whole workflow from computing diff binary between versions to dispatching diff binary per request.

Developed a desktop GUI in Python for streamline workers to input hardware specifications, analyze statistics from a batch of hardware, compare against historic trend, generate reports/powerpoints etc.

Developed a user forum website with ruby on rails, users can upload photos of their art works, create portfolios, vote and comment on others photos, receive email notifications, share links to fb/twitter etc.