Senior Full-Stack Engineer

はじめまして, I’m Thea.

I build and run production platforms: an eSIM storefront, a real-estate marketplace, and the AI systems behind them.

My background spans e-commerce, fintech, insurance, and travel, including platforms serving millions of users. Today I lead architecture, releases, and infrastructure across two companies.

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years shipping software

Millions

of users on platforms I've built

production products I lead today

20+

projects across 7 industries

What I do

Build

From MVPs to production-ready SaaS. I've shipped commerce platforms, marketplaces, and study apps end to end, schema to service worker.

Scale

Architecture, cloud infrastructure, DevOps, and performance. I've optimized systems serving millions of users and cut an infra bill by 80%.

Solve

Complex engineering problems with practical solutions: cross-domain auth, AI data pipelines, legacy migrations that land without downtime.

Case studies

Real systems, real constraints, real trade-offs.

All case studies

Real Estate Marketplace

Client work

Building and launching a property viewing platform end to end, from SSR performance to the AI that assigns leads to agents.

Next.jsReactTypeScriptNode.jsPython

-80%

infrastructure cost

eSIM Commerce Platform

Client work

Owning a travel eSIM storefront end to end, checkout, payments, automated QR fulfillment, and the cross-domain auth that ties a multi-site product together.

Next.jsReactTypeScriptNode.jsExpress

Zero-touch

QR fulfillment after payment

nihongojouzu.jp

Live

A production JLPT study PWA with spaced repetition, push notifications, and a custom furigana engine, built solo, end to end.

Next.jsReactTypeScriptZustandSupabase

PWA

installable, offline-aware

AI Property Pipeline

Client work

Replacing manual real-estate data entry with a Claude-powered pipeline that runs while the team sleeps, scrape, extract, validate, deliver.

Claude APIAnthropic SDKPythonPostgreSQLNode.js

manual data-entry hours

Lead Inquiry Automation

Client work

An AI triage desk for a real-estate brokerage, every inquiry from email, Meta ads, and walk-ins classified, deduplicated, and routed to the right agent through Slack.

PythonFastAPIClaude APISlack APIGmail API

3 → 1

lead sources, one triage flow

Online Travel Agency Platform

Client work

Designing the backend for a new OTA product, partner API integrations behind clean adapter seams, and growing the team that ships it.

Node.jsExpressTypeScriptMongoDBPostgreSQL

1 contract

for every partner API

From idea to production.

Whether you’re hiring or building, let’s talk about turning ideas into reliable software that scales.

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