Senior software engineer / GitHub

I'm Ryan.I build the systems behind AI tools.

Designing and scaling the backend for Copilot Chat since 2023. Nice to meet you.

@ryanjamescaldwell

Pixel-art landscapes at dusk: a coastal lighthouse, a desert canyon, and a forest waterfall.

Featured writingJune 17, 2026VS Code Blog

Improving token efficiency for GitHub Copilot in VS Code

How prompt caching, tool search, and WebSockets reduce Copilot's token usage and latency.

Cache Explorer comparing two Copilot requests and showing a 96.8% prompt cache hit

Currently focused on

Building backend infrastructure for agentic developer tools: the API platforms, inference routing, and reliability systems that make them work at scale.

The pace of AI development right now is incredible. I don't find it chaotic, just genuinely engaging. Inference is being applied in brand-new ways every day, and figuring out how to expose that functionality through the API is work I spend a lot of time thinking about.

Outside of work

Making pourovers and lattes at home.

Spending time with my wife, daughter, cat, and dog.

Keeping up with the latest AI tools.

Automating all the things with Home Assistant.