Here is some code that I've worked on professionally. You can find more details in my resume:

• 
  Khan Academy

  Khan Academy seeks to provide a free, world-class education for anyone, anywhere. I help develop their iOS app and Android app, as seen on The Verge, The Next Web, and Engadget.

• 
  Burner

  Burner provides temporary and disposable phone numbers for online dating, Craigslist, and more. While there I productionized the backend while increasing test coverage from 0% to over 90%. I also wrote the Android app in its entirety, as seen on Ars Technica, Gizmodo, and Lifehacker.

• 
  Google Docs

  Google Docs allows creating and editing documents online while collaborating with other users in real-time. I enhanced the sharing functionality for files and folders, and helped keep the product running smoothly in production.

And here are some open-source projects that I've worked on. You can find the rest on GitHub:

• Iron Cushion

  Benchmarks and load tests CouchDB, a document-oriented and RESTful database. Gathers statistics for both bulk insert and CRUD operations. I wrote this to verify that CouchDB could handle all the data that Burner would throw at it. Currently used by Cloudant.

• Tarsnap Manager

  Manages daily, weekly, and monthly backups on Tarsnap. When run as a daily cron job, older backups are deleted as newer ones are created, while more recent dates have smaller intervals between backups.

• Side-by-side Search Comparison Tool

  Compares side-by-side the results of two different search providers. Written so that Google search appliance customers could compare different scoring policies. After some press by ReadWriteWeb and Search Engine Watch, it was mistaken as a challenge to Bing.