• Founding engineer and co-lead for Duolingo ABC, an early literacy app for kids.

• Implemented new security features for Pages and Page admins as part of a company-wide election integrity effort.

• Developed experimental features focused on group video chat within the Messenger Real-Time Communication team.

• Employee #12 and sole developer of Duolingo's first iOS app. During this time the app was chosen by Apple as the 2013 App of the Year and became Duolingo's largest platform.

• Team lead for Tinycards, Duolingo's first educational app outside of language learning and one of Apple's Top 10 Apps of 2016.

• Tech lead for Duolingo's core learning products on iOS, Android, and web. Drove the development of new features, working with designers, engineers, and PMs to run experiments and improve key metrics.

• Owner of processor power management on Windows Phone 8, tuning low-level OS settings to optimize device power and performance.

• Developed automated experiments to find optimal power settings.

• Used light fields to render photorealistic environments in real time for large numbers of simultaneous users.

• Implemented interactive real-time networked physical simulations. A large-scale simulation, hosted on a server, was streamed to multiple low-end mobile devices, allowing users to interact with the same simulation in real time.