About me

I am Przemysław Zalewski, a senior full-stack engineer and technical lead from Wrocław, Poland. I have shipped React since 2017, with TypeScript and Node.js. Before that I spent ten years on C# and .NET, building my own Windows Phone and Windows Store apps with 3.7M+ downloads.

For nine years I have run products end to end at the same agency, solo or with a small team. I own what I ship: I monitor it, run it, debug it and page myself. Since 2023 I have put AI agents to work on real products. They get skills, guardrails, end-to-end tests and observability, and I review what they ship.

Recent work: Patriot Mail, an email client with iOS and macOS apps on the App Store since April 2026, and Sandtime.io, time tracking for 4,000+ freelancers and teams, where I have been the founding engineer since 2018. The details are in my resume.

Available now, in Wrocław or remote. Hiring for TypeScript, React or AI agents? See services, rates and the earliest start date, or write to me below.