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FoundingEngineer& 0→1 Builder

5 years in EdTech, leading three 0-to-1 product launches. Founding Engineer → PM & Tech Lead of Shinkenzemi √Route, scaling the team from 1 to 26 while architecting the full platform (Next.js × Java × Python). Most recently solo-built an educational content pipeline with Claude Code + Codex, reporting directly to the CIO. Now solo-building and operating a commercial SaaS hiring marketplace.

About Me→Projects

/0→1 Product Builder
/Java & Spring Boot
/TypeScript Full-Stack
/AI-Augmented Engineering
/LLM Pipeline Architecture
/Team Building 1→26

3×

0-to-1 Launches

1→26

Team Scaled (1→26)

Years of Engineering

Patent Co-inventor (JP 7815525)

01Career

Projects

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P—01

Shinkenzemi √Route

Founding Engineer → PM & Tech Lead (team scaled 1→26)

Apr 2024 – Mar 2025

Founded a 0-to-1 online learning platform for high schoolers, growing from a solo prototype to PM & Tech Lead of a 26-person team.

Reached monthly profitability within 3 months of launch

Next.jsReactTypeScriptTailwind CSSJava

P—02

Educational Content Pipeline

Solo engineer / architect (reporting to the CIO; product led by 2 PdMs)

Nov 2025 – Jul 2026

Solo-built an LLM pipeline that structures educational content, reporting directly to the CIO — 20,000+ questions linked to exam data problem-by-problem.

Structured 20,000+ questions and linked them to exam data problem-by-problem for the first time

PythonClaude APIGPT APIVLM / OCRDatabricks

P—03

Remote Crowd (HR-Tech Recruiting Marketplace)

Solo full-stack contract engineer

Oct 2025 – Present (beta Feb 2026, public launch Jul 2026)

Shipping Remote Crowd, a two-sided HR-tech recruiting marketplace (a client project for remolabo Inc.), single-handedly — from design and implementation to infrastructure and operations.

Shipped a commercial SaaS solo — from design and implementation to infrastructure and operations (beta Feb 2026, public launch Jul 2026)

Next.js 14NestJSTypeScriptTurborepoPostgreSQL

02About

Hi, I'm Eiji

Five years in EdTech at Benesse (2021–2026). I've led three 0-to-1 product launches — founding Shinkenzemi √Route, a learning platform for high schoolers, as its first engineer and scaling the team from 1 to 26. Most recently I reported directly to the CIO, solo-building an AI content pipeline with Claude Code + Codex. Today I'm solo-building and operating a commercial SaaS hiring marketplace.

Backend: Java / Spring Boot (4 yrs) & full-stack TypeScript — robust APIs and production SaaS
AI & LLM: AI-driven development with Claude Code + Codex, and LLM pipeline design
Cloud: Azure (4+ yrs) and AWS + Terraform — scalable infrastructure as code

Core Technologies

JavaSpring BootTypeScriptNext.jsNestJSAzureAWSClaude Code

Full Profile→

03Blog

Latest Blog Posts

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Note↗

From Stagnation to Resolve: At 28, I Am Moving to the UK This Summer

Written in Japanese

#UK#Working Holiday#Career

June 19, 2026

Note↗

How AI Changed the Way I Learn English Vocabulary — The Prompt I Use Every Day

Written in Japanese

Plenty of people studying English have a respectable TOEIC score and still find that none of it comes out in an actual conversation.

#AI#English Learning#Prompting

January 11, 2026

Note↗

Looking Back on 2025: A Year of Stagnation with Light Breaking Through, and Resolve for 2026

Written in Japanese

If I had to sum up 2025 in a phrase, it was a year of stagnation with light breaking through — the frustration of marking time without feeling myself grow.

#Retrospective#Career

January 10, 2026