what i'vebuiltabout me
Sam Xia

hey, i'm sam!

where i've worked

what i've built

on the job

  • Kelley Blue Book · Software Engineering Intern

    Jun 2026 – Aug 2026

    • Hackathon winner

      1st of 14 teams at Cox's intern hackathon. Built 3 games and a car-buying garage into the KBB app with Flutter, and one game is now coming to kbb.com. Watch the demo.

    • Car payment calculators

      Rebuilt KBB's auto loan, car affordability and car lease calculators from start to finish: the screens, built to match the designs exactly, and all the math behind them.

    • Repair or Replace results

      Built the page that tells drivers what to do next once KBB's Repair or Replace tool gives its answer, with 39 tests covering every requirement. See it live.

    • Switching on the firewall

      Turned the AWS firewall in front of KBB and Autotrader from watch-only to blocking, after checking 18.3M real requests so no real users would be shut out. It can be undone in one step.

  • LendAPI · Software Engineering Intern

    Jun 2025 – Aug 2025

    • A rules engine for loans

      Built the engine that approves or declines loan applications from a set of rules, written in its own small rule language. Any past decision can be reproduced exactly.

    • A record of every decision

      Every decision is saved with its inputs, the rules that fired and the reason for any decline. Fake applicants let it be tested at scale without real customer data.

    • Trying rule changes safely

      A replay tool runs new rules against 293 past decisions and shows which ones would change and why, before anything reaches real customers. A full replay takes seconds.

on my own time

  • to be continued…