Karsey Renfert

Software Licensing Service

Solo-run SaaS that authenticates software licenses for any kind of program. I built the API, the web platform, a novel system for detecting and banning temporary email addresses at signup, and the Stripe billing flow. Recently, I added an IP geolocation feature, which ties into a log analyzer to detect suspicious activity.

• 150,000+ users served
• 10,000+ monthly users
• Used by hundreds of developers
• Profitable within 30 days of launch

File Distribution Service

A developer-oriented storage product with a clean API and deep integration with my authentication platform.

• 500,000+ downloads served

Donut Rodeo

My studio. Under this name, I build websites, Chrome extensions, and open-source tooling. Recent work includes a Chrome extension, data formatting software, and an open-source website for local radio enthusiasts.

• Bib Bypasser (Chrome ext)
• MadMesh.net
• YouMessage.Me (defunct)

Sound Devices

After completing my degree (and many years of interning here), I joined Sound Devices as a full-time software engineer in 2024. I've had the pleasure of working on a variety of projects, from low-level C++ development for a smart battery charger, to mobile and web app development.

Snek

A small snake game. Eat the apple, grow, try not to hit the walls.

WASD or arrow keys to move · P or space to pause

Bumpy Bird

Keep flying, and avoid hitting obstacles at all costs!.

A and B keys to move · P or space to pause