01問題
Understand the Problem
Before coding, understand the requirements, constraints and business rules.
東京Software Engineering
Backend Developer building systems, APIs and reliable software.
I build backend systems with TypeScript, Node.js and NestJS, combining clean architecture, business logic, APIs, databases and infrastructure to turn ideas into working software.
Open to opportunitiesCurrently learning · building · improving
Scroll 知識About
About Me
I'm a backend-focused developer interested in understanding how software works beyond the interface. My learning process is centered around programming logic, business rules, APIs, databases, architecture and infrastructure.
I enjoy taking an idea, breaking it into requirements, designing the system, implementing the backend, connecting the frontend and understanding the infrastructure required to make everything work together.
I build software by combining programming fundamentals, business logic, system architecture and practical engineering. I am continuously expanding my knowledge to evolve professionally and contribute to building reliable solutions and improving products.
Process
- Learn学習
- Design設計
- Build構築
- Test検証
- Improve成長
What I know
TypeScript, Node.js, NestJS, REST design, PostgreSQL and Prisma, layered architecture, Docker basics.
What I have built
A modular NestJS learning platform backend, its Next.js frontend, and a personal analytics dashboard.
What I'm learning
Deeper testing practices, observability, infrastructure, system design and distributed systems.
設計Philosophy
How I Think About Software
Five principles that shape how I approach a problem before, during and after writing code.
- 02設計
Design the System
Think about architecture, modules, APIs, data and responsibilities.
- 03構築
Build with Structure
Separate controllers, services, repositories, DTOs and infrastructure concerns.
- 04検証
Test and Debug
Use testing, logs, API clients and debugging to verify assumptions.
- 05成長
Keep Improving
Refactor, document, learn and improve the system continuously.
構築Selected work
Featured Projects
Three projects presented as technical case studies — the problem, the architecture, the engineering decisions and what each one taught me. Feature status is stated explicitly inside each case study.
01Learning Platform / Backend Engineering
Fluency OS構築
A full software ecosystem for Japanese language learning, combining spaced repetition, progress tracking, authentication, content management, immersion tracking and analytics.
BackendREST APINestJSTypeScriptPrismaPostgreSQLRedisDocker
flow
- ┌─ Frontend
- ├─ REST API
- ├─ Controllers
- ├─ Services
- ├─ Repositories
- ├─ Prisma
- └─ PostgreSQL
+ 3 supporting services
02Learning Interface / Full-Stack
Fluency OS — Frontend設計
A modern learning interface built to consume the Fluency OS backend and provide a complete experience for study, review, analytics and content management.
FrontendNext.jsReactTypeScriptTailwind CSSshadcn/uiZustandFramer MotionVitest
flow
- ┌─ Frontend
- ├─ REST API
- ├─ Backend
- └─ Database
03Productivity / Analytics Dashboard
Weekly Metrics System成長
A personal dashboard designed to track weekly progress across programming, Japanese study, schedule and review activities.
ReactNext.jsTypeScriptRechartsZustandFramer Motion
flow
- ┌─ Activity input
- ├─ State layer
- ├─ Aggregation
- └─ Charts & insights
技術Stack
Technology Stack
Grouped by category and weighted honestly. My primary focus is TypeScript → Node.js → NestJS → PostgreSQL → Prisma; React, Next.js, Docker, Git and GitHub are supporting skills I use regularly.
Languages
言語- TypeScriptPrimary focus
Primary language — typed domain models and APIs.
- JavaScriptPrimary focus
Language fundamentals, async behavior, runtime model.
Backend
基盤- Node.jsPrimary focus
Runtime for services, tooling and APIs.
- NestJSPrimary focus
Modular architecture, DI, layered structure.
- REST APIsPrimary focus
Contracts, validation, status codes, error shapes.
Database
データ- PostgreSQLPrimary focus
Relational modeling, relationships, queries.
- PrismaPrimary focus
Schema as source of truth, typed data access.
Frontend
画面- ReactWorking knowledge
Component composition and UI state.
- Next.jsWorking knowledge
Routing, rendering and app structure.
Infrastructure
環境- DockerWorking knowledge
Reproducible environments and services.
Development
道具- Git & GitHubWorking knowledge
Branching, history, code review workflow.
- CLI / TerminalWorking knowledge
Daily driver for builds, logs and debugging.
- IDEsWorking knowledge
Refactoring, navigation, debugging tools.
- AI-assisted developmentTooling
Used as a tool, not a substitute for understanding.
開発Scope
What I Build
The kinds of engineering problems I work with day to day.
APIs
Design and implementation of REST APIs.
Business Logic
Transforming requirements into software rules and workflows.
Architecture
Organizing systems into maintainable modules and responsibilities.
Databases
Data modeling, relationships, persistence and query organization.
Authentication
Sessions, JWT, authorization and protected resources.
Infrastructure
Docker, environments and application infrastructure.
Testing
Unit tests, integration tests and validation of behavior.
Debugging
Investigating errors, logs, requests, data and unexpected behavior.
道具Workstation
Engineering Toolkit
The tools I actually keep open while building and debugging.
erik@tokyo ~ toolkit
$terminal— daily driver — builds, logs, migrations
$git— branching, history, review workflow
$github— repositories, issues, collaboration
$postman— API requests, contracts, debugging
$docker— containers and local infrastructure
$vscode— refactoring, navigation, debugger
$ai-tools— assisted development, reviewed by hand
$database— psql, schema, queries, inspection
$rest— contracts, status codes, payload design
成長Growth
Always Building. Always Learning.
My goal is to keep expanding my understanding of software engineering — from programming fundamentals and backend architecture to databases, infrastructure, system design and distributed systems.
- 01Fundamentals
- 02Backend
- 03Architecture
- 04Infrastructure
- 05System Design
継続Continuous improvement
未来 / Future
証明Repositories
Code is the proof.
Every project on this page is public. 3 selected repositories — open them and read the structure.
@Erik02T
Backend-focused repositories, frontend clients and personal engineering tools.
未来Direction
Where I'm Going
I want to continue evolving as a software engineer, deepen my backend expertise and contribute to products by building reliable systems, solving technical problems and continuously improving the way software is designed and delivered.