• Implemented a feature that fills in a day-to-day itinerary for any of 2,000 cities around the world using Typescript, Node.js, and React which showed 6% greater 8-week user retention and was featured on [a daytime talk show](https://danielkoh.dev/ctv)

• Led a team of 3 engineers to optimize our React Native app by patching upstream dependencies to cache frequently called functions, eliminating performance-related Play Store complaints over 3 months and raising the app rating from 4.6 to 4.7 stars

• Collaborated with the lead designer to implement a new mobile web landing page in React for post-ad-click users, increasing start trial rates by 10%

• Built a service in Node.js to compile trip plan updates and integrate them into an existing notification system, improving re-engagement and boosting 8-week retention by 4%

• Delivered an LLM-based email parsing system to replace a legacy AwardWallet contract, pioneering a batch-testing framework for rapid prompt optimization and securing a 12% lift in positive user feedback and a seamless transition ahead of the contract renewal deadline

• Initiated CSS overhaul to make frontend responsive with flexbox and increase lighthouse score by 30 points

• Refactored Java Spring Boot backend to cut down build times by 15x, boosting developer productivity and cutting CI/CD costs

• Fixed critical bugs in use of Redux store, unblocking development of key features and receiving praise from stakeholders during sprint review

• Built a Python Flask web app to automate participant selection for research study, reducing processing time from 2 days to 5 seconds and demonstrating scalability for high-efficiency workflows

• Served as a key coordinator between multiple labs, university departments, and external vendors to facilitate a large-scale research project, ensuring seamless communication and collaboration

• Mentored, trained, and supervised a team of undergraduate assistants in laboratory procedures, fostering their development and ensuring data quality