Selected
Systems
Business systems built for client operations. Client names and screenshots are withheld — the stack and my scope are described instead.
2025.10 —
EC の不正受注チェックツール。
Screens uploaded order data against a growing set of fraud rules. The rule engine sits in one module — around 50 KB now — so a new rule lands without touching the rest of the app.
2026.01 —
督促回収額の予測ツール。
Replaces an averaging heuristic nobody could plan against. Forecast and actuals are charted together so the operations team can judge the model for themselves rather than trust it blindly.
2025.04 – 07
企業向け AI ツール管理ポータル。
Admins manage companies, users, tools and permissions; each company's staff see only what is assigned to them. Permission checks live in one place, so a new screen cannot quietly leak access. Auth is hand-rolled on bcrypt.
2025.08 – 2026.01
Google マップ口コミの管理・自動返信ツール。
Collects Google Maps reviews for restaurants and drafts replies with an LLM. Drafts are never posted automatically — a person approves every one. Subscription billing runs on Stripe.
2025.10 – 12
学会発表の質疑応答を支援する RAG システム。
Presenters upload papers and slides ahead of a talk. Spoken questions are matched against that material and answered with the source passage attached, so the presenter can verify the answer before saying it out loud.
2025.08 – 10
プレスリリース配信メールの自動生成。
Pulls text out of release PDFs — falling back to page images when the layout defeats extraction — and drafts distribution mail per recipient for a human to finish.
2025.10
GAS 製の PDF アップロード＆フォーム自動生成。
A Google Apps Script web app: drop in a PDF, it lands in Drive and a matching Google Form is generated. Split into two steps to stay inside the GAS execution limit.
About
I'm a solo developer based in Japan. By day I build business systems for companies — fraud detection, forecasting, multi-tenant portals, RAG search — with Next.js and TypeScript on the front and FastAPI or Flask behind it. On my own time I ship iOS apps — four are on the App Store — and the occasional website when a question needs one.
Design, implementation, deployment and the support inbox afterwards tend to land on the same person here. That is usually me.
日本拠点の開発者。業務システムと iOS アプリを、要件整理から運用まで一人で作っています。
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