DuolingoStaff Software Engineer
January 2014 - Present
I wrote the current incarnations of the flagship web app and API backend, repaying years of technical debt and reducing page load times by 80%.
Duolingo for WindowsStaff Software Engineer
August 2014 - Present
Within a month of its release into the wild, the app reached #1 in the store's Education category with a 4.7 star rating based on over 5000 reviews.
OpenAIMember of Technical Staff
April 2017 - June 2017
OpenAI is a nonprofit research lab founded by Elon Musk and Sam Altman in 2015 with the goal of creating safe, human-level artificial intelligence.
I currently work on the infrastructure team, developing internal tools and managing our clusters.
Duolingo English TestStaff Software Engineer
February 2014 - June 2015
The DET is an ambitious attempt to replace overpriced language certification exams like the TOEFL and IELTS with Duolingo's own remotely proctored $50 exam. It's now used by organizations ranging from Uber to Yale University.
Triviality is a free online game that I designed and coded in order to learn React.
Inspired by Classic Trivia and What's the Lyric, Triviality is a question-and-answer quiz app that pulls data from the J! Archive via jService. It's optimized for the Amazon Fire TV but also works with keyboard, mouse, and/or touchscreen.
Duolingo EarthDecember 2015
For the 2015 company hackathon, coworker Karin Tsai and I created a WebGL map that visualizes global user activity in realtime. Come visit Duolingo HQ and you'll see it on display in the lobby.
Face-Recognizing Page TurnerApril 2015
I got tired of fiddling with the mouse while practicing guitar at the computer, so I shamelessly shoved years of computer vision research into an automation script. More details here.
Jeopardy! SimulatorDecember 2014
True Daily Double is a free multiplayer online game that I designed and coded in order to learn Angular.
CIFEr Hedge Fund CompetitionSeptember 2013 - February 2014
I put together a mock trading webapp that hosted a 40-day educational contest featured in the IEEE's Computational Intelligence for Financial Engineering & Economics conference in London. The results were published at WSC '14.
Epic SystemsResearch and Development Intern
May 2013 - August 2013
MiscellaneousAugust 2007 - Present
October 2012 - December 2013
Ticketmelon is a ticket sales and event promotion app based in Bangkok, Thailand. A few high school classmates, my college roommate, and I worked on the initial version.
Stock Market SimulationSeptember 2012 - September 2013
3D Neuron ModelerOctober 2011
My neuroscience research experience lasted for just a few days, but during that time I came across some test data that proved suitable for trying out WebGL months later.
Here's a demo. There are almost 6000 shapes, so it may take a few seconds after you load the data before anything appears.
Raytracing, Morphing, and OpenGLAugust 2012 - December 2012
Very significant portions of my allotted time in this world were spent on CS 4810: Intro to Graphics. A particularly inordinate number of hours was spent on the second project. The results were definitely worth it.
Music2004 - Present
After six years of playing clarinet in "sitting" band, I joined UVa's marching band for fun and profit. (Willingness to run around carrying a 30-pound sousaphone has its perks.)
chaidarun.comJuly 2010 - Present
The styles and scripts are handcoded in Sublime Text and stitched together with Jekyll and Sass.
Graphing Calculator ProgramsAugust 2007 - December 2013
The TI-84 graphing calculator required for my math analysis class gave me my first taste of coding.
I still have and use the same calculator for my programs, which range from games like Blackjack and Simon (9th grade) to binomial tree option pricers (last semester of college).