Great Clips
Lead UI architect for Great Clips' mobile-first web app, serving 2.5M+ users a month on Next.js/React SSR, and lead backend engineer for its Live Activities microservice serving 5M+ users across iOS, Android, and web.
Visit project ↗Minneapolis, MN / a personal corner
Code, coffee, care.
I'm Sergio, a software engineer building useful tools, small experiments, and things I want to use. Usually with a coffee nearby.
Press Escape to turn the lights back on.
Fresh cup. First sip’s the best.
Selected work / personal pursuits
Brewed at home and work.
Many bags of coffee code to choose from.
01 / WORK
Target.com A/B Testing Platform
Led the UI team for an internal A/B testing platform used across Target.com and its iOS/Android apps, testing variations on 50M+ users a month.
Pericle
Led AI-first, solo end-to-end development of Pericle, a board game platform built with React/TypeScript and .NET Core on Azure.
Visit project ↗02 / PERSONAL
sergn.io
Coffee, wings, N/A beers, reubens, maple syrup, and notes.
Visit project ↗Golden Rune Calculator
A solo-built "make exact change" calculator for Elden Ring, abstracting the game's currency math to tell you the optimal Runes to spend on a desired upgrade without overshooting. Built with Next.js, live since March 2022.
Visit project ↗1 Hour Workout
A solo-built desktop workout app (Electron/React/TypeScript/SQLite) for timed group workouts - tracks each person's max weights, auto-calculates the day's working weight, and runs an automatic timer that switches exercises so multiple people can work out together without conflicting.
Visit project ↗A few places along the way.
A little flight through my professional life.
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Destination 01 Jun 2016 - Dec 2017
Thomson Reuters
Engineer
Refactored the team's codebase to higher coding standards, built out REST endpoints, and rewrote the Angular frontend, while mentoring developers and establishing an end-to-end testing practice.
Destination 02 Feb 2019 - April 2021
Target
Senior Engineer
Combined hands-on UI work with mentoring five engineers, teaching testing practices, and presenting UI fundamentals to 650+ engineers each year.
Destination 03 April 2021 - Jan 2024
Long Dog Games
GTM Engineer
Owned the product's UX design alongside its engineering, working through video playback, authentication, caching, and optimistic updates while using feedback to guide improvements.
Destination 04 Jan 2024 - Present
Livefront
Senior Engineer
Serves as lead engineer for the Great Clips web app, owning component architecture and engineering standards while mentoring engineers and sharing practices through monthly talks on agentic engineering and AI ethics.