# David Klionsky

> Co-founder at PlayScout | ex-Duolingo, Meta, Microsoft

Location: Bellevue, Washington, United States
Profile: https://flows.cv/davidklionsky

## Work Experience
### Senior Staff Software Engineer @ Duolingo
Jan 2018 – Jan 2023 | Seattle, Washington, United States
• Founding engineer and co-lead for Duolingo ABC, an early literacy app for kids.

### Software Engineer @ Facebook
Jan 2017 – Jan 2018 | Seattle, WA
• Implemented new security features for Pages and Page admins as part of a company-wide election integrity effort.
• Developed experimental features focused on group video chat within the Messenger Real-Time Communication team.

### Senior Staff Software Engineer @ Duolingo
Jan 2012 – Jan 2017 | Pittsburgh, PA
• Employee #12 and sole developer of Duolingo's first iOS app. During this time the app was chosen by Apple as the 2013 App of the Year and became Duolingo's largest platform.
• Team lead for Tinycards, Duolingo's first educational app outside of language learning and one of Apple's Top 10 Apps of 2016.
• Tech lead for Duolingo's core learning products on iOS, Android, and web. Drove the development of new features, working with designers, engineers, and PMs to run experiments and improve key metrics.

### Software Development Engineer @ Microsoft
Jan 2012 – Jan 2012 | Redmond, WA
• Owner of processor power management on Windows Phone 8, tuning low-level OS settings to optimize device power and performance.
• Developed automated experiments to find optimal power settings.

### Master's student @ Carnegie Mellon University
Jan 2010 – Jan 2012 | Pittsburgh, PA
• Used light fields to render photorealistic environments in real time for large numbers of simultaneous users.
• Implemented interactive real-time networked physical simulations. A large-scale simulation, hosted on a server, was streamed to multiple low-end mobile devices, allowing users to interact with the same simulation in real time.

### Software Development Engineer Intern @ Microsoft
Jan 2010 – Jan 2010 | Redmond, WA
• Measured XNA graphics performance for the first release of Windows Phone.
• Implemented a tool for identifying performance regressions in XNA apps.
• Authored a document for XNA game developers outlining best practices for good performance.

### Software Engineering Intern @ TerraSim
Jan 2009 – Jan 2009 | Pittsburgh, PA
• Developed software which analyzed building floor plans and automatically generated human-navigable paths within those buildings for use by game AI.
• Wrote importers and exporters for TerraSim's 3D model formats.


## Education
### Master's degree in Computer Science
Carnegie Mellon University
Jan 2010 – Jan 2011

### Dual Degree in Bachelor of Science (B.S.), Computer Science and Cognitive Science
Carnegie Mellon University
Jan 2006 – Jan 2010


## Contact & Social
- LinkedIn: https://linkedin.com/in/davidklionsky
- Website: https://davidklionsky.com

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Source: https://flows.cv/davidklionsky
JSON Resume: https://flows.cv/davidklionsky/resume.json
Last updated: 2026-03-22