New startup!

Co-founded Matrix Operations, a high-frequency trading firm operating in NYC and London. I designed the software infrastructure and am responsible for realtime performance of the trading systems.

We built a new payments system for the web that works by exchanging existing brand gift cards (Starbucks, Best Buy, etc.). Profitable with no outside investment. Hundreds of customers including privateinternetaccess.com.I coauthored v1 of the payments system. With <8k lines of clojure code it processed >$1M/month in transactions. (Nowadays much the than that.)http://www.paygarden.com

Almost as fun as building software is helping others do so. I personally invested in the 1st round of funding of Meteor, Stypi, Parse, Boosted Boards, Clever, Kamcord, PlanGrid, Imgix, Light Table, Kite, and Red Planet Labs.

One of 6 full-time partners in YCombinator from 2011-2012, working directly with Paul Graham.I read applications, interviewed, and mentored nascent startups on product strategy, software architecture, early team formation, and fundraising.200+ investments from batches I partnered include Amplitude, Instacart, Coinbase, PlanGrid, Gusto, Parse, Firebase, Zapier, Stypi, Codecademy, Streak, CrowdTilt, FarmLogs, LendUp, HackPad, MatterPort, Anyperk, SocialCam, Boosted Boards, Clever, Kamcord, Lever, Soylent, Light Table, and Plivo.I also hacked on the lisp code to news.ycombinator.com.http://ycombinator.com/http://news.ycombinator.com/

Etherpad was the first web-based realtime collaborative text editor. I coauthored v1 of etherpad, and in the process helped pioneer running JavaScript as a server-side language. (Before node.js).Acquired by Google in 2009http://en.wikipedia.org/wiki/Etherpadhttp://www.etherpad.org

Developed new algorithms for google web search and google image search.

After winning BattleCode in 2003, I become a director along with David Greenspan. We did a lot to grow the competition in size and scope, including rewriting all the software and implementing a new RoboVM.

Wrote NLP algorithms for the Microsoft Word proofing tools (grammar checker, spell checker, etc.).

implemented a network traffic analysis system; investigated graylisting for email spam prevention; and prototyped a DARPA research project for software algorithms to control autonomous military vehicles.

Researched software agents for cell phones.

Added mobile phone support to an armed forces contract job to create a command-center & field operations prototype of next generation battle management.