Senior Unity & Software Engineer

Mark Yamashita

I design and ship realtime systems, networking stacks, and tools that help teams build games and interactive products with confidence.

View selected work View experience Download resume (PDF)
Unity · C# · WebGL · gRPC Web · iOS

What I focus on

Architecting clean Unity UI and game systems for mobile, desktop, and WebGL.
Building client-server systems, including APIs, gRPC-Web clients, REST integrations, and deterministic replay tools.
Profiling and tuning frame rate, memory, and build size on constrained hardware.
Creating editor tools, validators, and workflows that improve development speed and reliability.
Prioritizing maintainable architecture with readable code, clear boundaries, and data flow that teams can extend.
Building systems with debuggability in mind using structured logging, predictable behavior, and tools to reproduce complex issues.
Designing APIs with clear contracts, validation at the boundary, and structured error handling.
Picking up new domains quickly and delivering reliable systems across frontend, backend, and client platforms.

Selected work

PariMAX WebGL HHR Client

1/ST Technology · Unity · WebGL · gRPC Web

Led development of PariMAX’s first Unity WebGL client for real money historical horse racing games. Built a reusable gRPC Web networking package with typed requests, retries, and structured logging used across titles.

  • Converted a legacy Unity PC title to WebGL with build-size, performance, and cross-browser optimizations.
  • Built the entire Unity gRPC-Web integration path using a custom JavaScript bridge, Webpack bundling, and .jslib interop.
  • Collaborated with backend teams on secure, server-authoritative flows.

WhoAmMAI

Personal project · Cloudflare Workers · React · TypeScript · LLM integration

LLM-powered daily guessing game exploring serverless APIs, structured model output, validation, and constrained game loops.

  • Built a React web app with a Cloudflare Worker API.
  • Designed structured JSON output boundaries for LLM intent parsing and response handling.
  • Added API validation, structured error responses, and protected admin-route patterns.
  • Designed API boundaries to separate parsing, validation, and game logic for maintainability.

View GitHub repo

BotBattle

Personal project · Go backend · TypeScript frontend

A competitive bot platform with a deterministic battle loop and replayable simulations. Designed as a way to deepen backend, API, and systems skills beyond game clients.

  • Implemented a bot upload API with validation and structured error responses.
  • Outlined the architecture for a seedable battle engine supporting reproducible matches and debugging.
  • Designed a deterministic simulation model to enable reproducible matches and debugging.

Experience

Senior Software Engineer

1/ST Technology – AmTote International · Remote

2023 – Present
  • Led Unity WebGL client development for real time HHR casino games, including PariMAX’s first WebGL title.
  • Built and maintained a gRPC Web networking package reused across products.
  • Created editor tools and validators that improved content workflows and data safety.
  • Profiled and optimized frame rate and memory on constrained hardware.

Unity Game Developer

Igloosoft Games · Remote

2021 – 2023
  • Implemented core systems for a 2D survival and colony game across PC and consoles.
  • Worked on AI, animation, and performance tuning for large worlds.
  • Built internal tools to speed up world generation and designer workflows.

Lead iOS Developer

24x7digital · Los Angeles, CA

2008 – 2025
  • Created the TeachMe app series, reaching more than two million downloads.
  • Modernized Aw Craps into a freemium title with improved purchase and restore flows.
  • Prototyped a VR version of BC Blackjack for Meta Quest using Unity XR and OpenXR.

Contact

I am interested in roles where I can solve hard engineering problems across systems, backend, and mobile, building modern, efficient, and maintainable solutions. I love designing software that is robust, performant, and thoughtfully engineered, regardless of platform or language.

Email: yama@yama.com

LinkedIn: linkedin.com/in/markyama