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Achievement: Galaxy Brainx4Achievement: Pair Extraordinairex3Achievement: QuickdrawAchievement: YOLOAchievement: StarstruckAchievement: Arctic Code Vault ContributorAchievement: Pull Sharkx3

Achievements

Achievement: Galaxy Brainx4Achievement: Pair Extraordinairex3Achievement: QuickdrawAchievement: YOLOAchievement: StarstruckAchievement: Arctic Code Vault ContributorAchievement: Pull Sharkx3

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yhay81/README.md
Yusuke Hayashi — engineering systems that ship

Portfolio · Haya Inc. · Zenn · LinkedIn · Email

Software engineer × product builder, based in Tokyo.
I turn ambiguous problems into production systems—architecture, implementation, evaluation, delivery, and operation.

01 / AI SYSTEMS

LLM integration, RAG pipelines, evaluation, and human-in-the-loop workflows designed for production constraints.

LLM RAG EVALS 		02 / SYSTEMS & TOOLING

Small, dependable developer tools with clear APIs, native performance, and low operational cost.

PYTHON RUST APIs 		03 / VERIFICATION & SECURITY

Reproducible baselines, bounded tools, evidence-backed validation, and responsible disclosure.

REPRO SECURITY EVIDENCE

Proof of work

Shipped system Evidence
HayaSend An early-beta, customer-owned transactional email foundation with Resend-compatible APIs, durable delivery records, and deployable infrastructure.
Hayate ecosystem A web-standards-first Python framework spanning ASGI, Cloudflare Workers, and AWS Lambda, with coordinated auth, MCP, OpenAPI, admin, HTMX, and scaffolding packages.
AI Partners + Demand Publicly accessible discovery surfaces that separate AI-adoption partner research from active project demand.

Current operating loop · frame the problem → model the system → ship a thin slice → measure reality → harden what matters

At Haya Inc., I work on production AI adoption and the engineering systems around it—from technical framing through rollout and team enablement.

Engineering footprint

Integrated GitHub engineering metrics for Yusuke Hayashi

First-party public GitHub signals, regenerated daily with a versioned API and no coding-time vanity metrics.

Latest writing

Outside work, I am usually on a road bike. For consulting, product engineering, or AI adoption inquiries, visit Haya Inc. or get in touch.

Pinned Loading

  1. haya-inc/wasmhatch haya-inc/wasmhatch Public

    The AI assistant that actually does the work — right in your browser tab. No server, no install, no account. Bring your own key or use Chrome's built-in AI; creates Google Docs, Sheets, and Slides;…

    TypeScript 1 6

  2. pylopdf pylopdf Public

    PDF editing, rendering, text extraction, and generation for Python, powered by Rust. pymupdf-style API without the AGPL — MIT, zero dependencies, lightweight wheels, WebAssembly-ready.

    Rust 2

  3. GASlacker GASlacker Public

    Slack Web API client for Google Apps Script — 168 methods, rate-limit retries, file uploads, OAuth v2, zero runtime dependencies

    TypeScript 30 10

  4. gh-freshclone gh-freshclone Public

    Compile and prove the fastest trustworthy baseline for a GitHub repository.

    Python 1

  5. gettext-tstrings gettext-tstrings Public

    Safe, fast gettext and Babel integration for Python t-strings

    Python 3

  6. public-data-catalog public-data-catalog Public

    Japanese-first, tested recipes for reproducible public-data retrieval with provenance, licensing, and freshness checks.

    Python