KYKevin Yang

Open to new roles, Honolulu or remote

Kevin Yang

Full-stack software engineer who builds systems that hold up under real schedules.

6+ years in TypeScript, React, React Native, Node.js, and GraphQL. I spent five years at OTTO Sport AI owning the league scheduling engine, and since March 2026 I've been building two iOS apps in React Native.

Faster schedule generation
6 times
30+ seconds down to about 5 on 1,000+ game stress tests
Less manual scheduling
Up to 75 percent
Up to 75% less time creating league schedules by hand
Microservices brought under test
More than 20
Shared test helpers built first so the team could work in parallel, with CI failing any service under 80% coverage
01

Selected work

OTTO Sport AI · 2021 – 2026 · Technical owner

League scheduling engine

The engine that builds season schedules for youth sports leagues, running on a platform of 50+ independently deployed microservices. I led its architecture and coordinated 2 to 3 engineers on matchup generation, cutting manual schedule creation time by up to 75%.

  1. Constraints

    Built the conflict engine that fits games into open slots using per-grouping rules for games per team, dates, time windows, locations, game length, and coach conflicts.

  2. Speed

    Rebuilt conflict checks on 5 minute slots, taking generation from 30+ seconds to about 5 on 1,000+ game stress tests.

  3. Extensibility

    Designed matchup generation around the Strategy pattern so new league formats needed no scheduler changes.

  4. Migration

    Rebuilt legacy V1 scheduling features in V3, helping move the last 3 large clients off V1.

OTTO Sport AI · Technical owner · See Fig. 1

Embeddable schedule and standings widgets

The schedules and standings that organizations embed on their own websites. I owned the widgets alongside the scheduling engine.

  1. Embeds

    Created embeddable HTML and CSS widgets for schedules and standings.

  2. CMS

    Extended the existing Ruby CMS so organizations could add the widgets to their own sites.

  3. Contracts

    Kept API contracts and migrations backward compatible across independently deployed services.

Apps and projects

iOS · 2026

Imposter In App Store review

A pass-the-phone party game for 3 to 12 players. Everyone gets the same secret word except the imposters, who have to bluff. Built with animated reveals, a lifetime in-app purchase, and ads. Before submitting, I wrote 100+ Jest tests and ran two release QA audits covering purchases, restores, and edge cases.

React Native · TypeScript · Reanimated · Jest · AsyncStorage

  • Title screen asking who's the imposter, billed as the party bluffing game.
  • Each player swipes up to peek at the secret word, then passes the phone.
  • The imposter's reveal screen, telling them to blend in and not get caught.
  • Voting screen where players pick who they think the imposter is.
02

Experience

  1. 2021 – 2026

    Software Engineer @ OTTO Sport AI

    Formerly Demosphere · Scheduling engine and widgets covered in Selected work

    • Built new Next.js UI for the OTTO platform as it branched off the Demosphere web app.
    • Built live game tracking in React Native with PubNub and MongoDB, syncing scores and timers across devices.
    • Tested React Native builds on real iOS and Android devices through SauceLabs before each release.
    • Built the shared test factories, database helpers, and auth test utilities that let the team bring automated tests to 20+ Node and GraphQL microservices in parallel, with CI failing any service under 80% coverage. It came out of a team retro on QA and engineering handoffs, and it caught bugs in CI before they reached QA.
    • Took part in architecture discussions on service boundaries and reducing coupling between services.
    • Led production deployments and rollbacks, and triaged 5 to 10 issues a week on a 6-person on-call rotation using CloudWatch logs, Grafana metrics, and Firebase crash trends, then ran root cause analysis across service boundaries.
  2. 2020 – 2021

    Software Engineer @ DCS Business

    • Built full-stack IoT monitoring on a 3 to 4 person team, giving businesses live and historical sensor views across all their locations through MQTT, Socket.io, and MySQL.
    • Added AWS SNS and Nodemailer email alerts with configurable thresholds, event counts, and time windows, so businesses were notified automatically instead of watching dashboards.
  3. 2019 – 2020

    QA Engineer @ Hive Media Group

    • Smoke tested every UI change across about 25 publishing sites, catching regressions missed on the site being changed.
    • Reproduced bugs, verified fixes, and tested A/B experiments and regressions, with Selenium for some automation.
  4. 2017 – 2019

    Accounts Receivable Representative @ FirstService Residential

    • Handled delinquency actions on homeowner accounts across 40+ HOA communities before moving into software.

Stack

TypeScript, JavaScript, SQL, Ruby, React, React Native, Next.js, Node.js, NestJS, GraphQL, REST

Data and cloud

MongoDB, PostgreSQL, MySQL, Redis, Prisma, AWS (S3, SNS, CloudWatch), Grafana, Firebase

Tooling

Git, GitHub Actions, Docker, Jest, Mocha, Playwright, Selenium, Claude Code, GitHub Copilot, ChatGPT

Education

LearningFuze, Software Engineering Immersive, 2019
UC Riverside, BS Business Administration, 2016

03 Contact

Let's build something that holds up.

I'm looking for software engineering, QA, support engineering, or solutions engineering roles, based in Honolulu and open to remote. The fastest way to reach me is email, and my resume is available on request.

[email protected]