I’m Joel Marquez, a Principal Engineering Manager at Microsoft. I lead a team of engineers that owns the globally distributed services behind Microsoft Teams calls and meetings — systems that handle billions of requests a day at 99.99%+ availability across commercial, government, and sovereign clouds. Running real-time communications at that scale is the foundation of my work.
The newest layer on that foundation is AI. My team also owns the voice-agent platform behind Teams Phone’s AI agents, and I led Intelligent Call Delegation — an AI agent that answers and handles calls on a user’s behalf — from concept to preview, staying hands-on in the real-time voice work along the way. The question driving my current work: how do agents become trustworthy enough for consequential work?
I joined Microsoft as a new-grad engineer in 2018 and reached Principal in 2026; I’m a co-inventor on 3 US patents. First-generation college graduate (computer science, University of Colorado Boulder), based in the Denver area. Outside of work I run, read, and play basketball — big Nuggets fan — and I write. This site is where my writing lives: mostly essays about agents, engineering leadership, and what I’m learning as I go.