DuolingoSenior Staff Software Engineer
January 2014 - Present
Duolingo is the most popular way to learn a language online and was named App of the Year by Apple.
I wrote (or rewrote) the flagship Duolingo apps for web and Windows, the DET web app, the API backend, and a plethora of internal tools. Now I lead Android and web development with a focus on code quality and developer tooling.
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 worked on the infrastructure team, developing internal tools and managing our clusters.
Chronofile is a personal time tracking app that I created to record and analyze the time, duration, and location of my daily activities. So far I've logged over 7000 events at the pace of about 20 per day.
It shows me whether I've been sleeping enough, holds me accountable for guitar practice, and occasionally helps answer questions like "Do I still have time for a haircut before the movie?"
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
See my GitHub profile for more side projects.
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 a 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.
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).