Stephen Marlow

I've built operational web products for Securitas Security Services USA, Johnson Controls, PRO Unlimited (now Magnit), and G4S across security, workforce management, and connected-building systems.

At Securitas, I led a React and TypeScript investigation workspace that brings incident history, alarm activity, access records, reports, and AI-assisted search into one operational flow. I designed AI-assisted search with source inspection, review history, explicit fallback states, and streaming search results.

At Johnson Controls, I built device onboarding, alarm review, equipment-state, and service-health workflows backed by C#/.NET and Java/Spring Boot APIs. I helped reduce p95 alarm-history API latency from about 1.8 seconds to roughly 640 milliseconds in load testing.

I follow features through APIs, relational data, authorization, testing, production support, and reversible rollouts. My backend work is often the heavier part of the job, while I also enjoy building clear React and TypeScript workflows with accessible, actionable error states.