Hi, my name is David Klionsky.

I built Duolingo's first iOS app.

I also led the team that made Tinycards, a free flashcard app for students.

Some of my other projects:

• @DailyBillBot, a bot that tweets bills recently introduced to Congress
• A calculator that breaks down how your tax dollars were spent
• An interactive explanation of how the Enigma machine worked
• Puzzles
• Abridged movie plots