Shaiful Islam Shabuj — Software Engineer, Yokohama Japan

01. whoami

About Me

I'm Shaiful Islam Shabuj, a Software Engineer with 7+ years of experience designing and operating mission-critical backend systems — from high-volume Order Management Systems serving 20+ apparel brands to multi-provider AI development pipelines.

I specialize in C#/.NET, cloud-native architectures across Azure, AWS, and GCP, and complex external API integrations. Clean architecture and SOLID principles are how I ship maintainable, production-grade systems.

I build a suite of open-source tools for AI-assisted development: devloop orchestrates agents, waymark controls what they can touch, teststop adversarially challenges them, and docuflow-mcp documents everything they produce. All four released June 2026.

🇯🇵 Yokohama, Japan · JLPT N3 · Multicultural engineering teams daily

7+

Years Experience

3

Companies in Japan

20+

Apparel Brands Served

8+

3rd-Party Integrations

N3

JLPT Japanese

268+

GitHub Repos

02. tech stack

Skills & Technologies

Languages

C# (6yr) JavaScript / TypeScript (6yr) PHP (5yr) Java (2yr) Python (2yr) Lua / LuaJIT (3yr) C / C++ (3yr)

Frameworks & Libraries

.NET Core / .NET 6+ ASP.NET Web API / MVC Entity Framework Dapper Angular React Node.js / Express Spring Boot Laravel

Databases & Caching

MSSQL / T-SQL (5yr) MySQL (6yr) MariaDB MongoDB Oracle DB Redis Memcache

Cloud & DevOps

Azure (App Service · WAF · Service Bus) AWS (EC2 · Fargate · ECR · RDS) GCP + Terraform Docker Kubernetes GitHub Actions Jenkins Grafana k6

AI & Agentic Development

Claude (Sonnet / Opus) OpenAI / GPT GitHub Copilot Codex LangChain MCP Servers Ollama HuggingFace RAG Systems

Security & Architecture

OWASP WAF / Azure WAF APPI / PII Compliance SOLID Principles Clean Architecture Microservices Domain-Driven Design Agile / Scrum

03. career

Work Experience

Avail Corporation

Feb 2023 – Present

Software Engineer (Full-Time)

📍 Yokohama, Japan · Technology Department

Production Management System (OMS)

Mission-critical OMS for the apparel industry — 20+ brands, 1,000+ internal and merchant users
Angular frontend + C# (.NET Framework / .NET 6+) Web API backend with MSSQL; led refactoring for performance and scalability
Azure cloud deployment, CI/CD via Jenkins / GitHub Actions in a 5-member cross-functional Scrum team

C#.NET 6+AngularMSSQLAzureJenkinsOpenAI LLM

Production Integration System — External REST API & Batch

8+ third-party integrations: logistics, customs, couriers, inspection services, e-commerce channels using C# / .NET
End-to-end ownership — design, error handling, structured logging, monitoring, root cause analysis
Cross-functional collaboration across Japan and multiple countries in a multicultural engineering team

C#JavaSpring BootAzure Service BusMSSQLCodex

Evolani Inc.

Jan 2022 – Jan 2023

Software Engineer (Full-Time)

📍 Tokyo, Japan · Technology Department

Business Card Management System

Full lifecycle: requirements → architecture → deployment; LuaJIT backend, JavaScript frontend, MySQL on AWS EC2 + RDS

LuaJITJavaScriptMySQLAWS

Voting Event Management System

High-volume real-time platform — thousands of concurrent participants; containerized via Docker
Redis / Memcache caching strategies; root cause analysis, production issue resolution

LuaPHPRedisDockerAWS

UltraX Corporation

Jan 2019 – Dec 2021

Software Engineer / Sub-Leader (Full-Time)

📍 Tokyo, Japan · Technology Department

Tracking System — Workflow Management

Led requirements and architecture for workflow platform serving 30+ internal users across order tracking and production
Sub-Leader: coordinated 5–7 member team, sprint delivery, code reviews, junior mentoring

PHPNode.jsMySQLCentOS Linux

CISCO Device Management Tool + Software Delivery System

C# / .NET internal tooling — device backup, management, SOLID principles throughout
Centralized log management; Linux server infrastructure (Ubuntu, CentOS) ops

C#.NETPHPC++Linux

04. builds

Featured Projects

the suite · all four released Jun 2026

🔁 devloop builds

🚦 waymark control plane

⚔️ teststop tests

📚 docuflow-mcp documents

Four tools. One system. devloop orchestrates the build pipeline, waymark controls what agents can touch, teststop adversarially challenges it, docuflow-mcp documents everything they produce.

▶ Watch the suite in action — ~80 sec · the problem, and the four tools that solve it

🔁

↗

devloop

The build layer of the suite. Multi-agent AI development pipeline — remote-controllable, self-healing, provider-flexible. Orchestrates Claude, Copilot, and OpenCode into a fully automated design → implement → review loop.

ShellMulti-AgentClaudeCopilot

Human oversight as a property of the system, not a property of the agent. MCP middleware that sits between an AI agent and the filesystem — every write and bash call is evaluated against your policy before it touches anything. The control plane of the suite; teststop's primary target.

TypeScriptMCPAI AgentsSecurity

MCP server letting AI agents build persistent, incrementally-maintained knowledge bases using the LLM Wiki pattern. Bridges ephemeral AI context with long-term knowledge retention. Dogfooded against three projects including this suite.

MCPTypeScriptKnowledge Base

TypeScript

v2.0.5 · Done

⚔️

↗

teststop

Adversarially tests AI-assisted codebases. Generates real-world edge cases using AI — race conditions, stale-state bugs, idempotency failures — then tracks confidence-to-retirement. Demonstrated live against waymark: 15 committed scenarios (3 critical, 71.4% confidence, 203s).

GoAdversarial AITesting

Go

v1.1.0 · Open Source

View All 268+ Repositories ↗

05. community

Open Source Activity

Active across the open-source AI and developer tooling ecosystem — following, forking, contributing to, and building on top of leading projects. Always at the cutting edge of autonomous AI systems.

anthropic / claude-code

microsoft / playwright

openai / openai-agents-python

langchain-ai / langchain

pydantic / pydantic-ai

supabase / supabase

n8n-io / n8n

mendableai / firecrawl

open-webui / open-webui

ollama / ollama

modelcontextprotocol / registry

NationalSecurityAgency / ghidra

PostgREST / postgrest

drawdb-io / drawdb

minio / minio

huggingface / transformers

06. writing & presence

Blog & Social

I write about backend engineering, AI-assisted development, agentic tooling, and life as a software engineer in Japan.

↗

dev.to

Technical articles on backend systems, .NET, AI/ML, cloud-native dev and engineering in Japan.

@shaifulshabuj29

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X / Twitter

Thoughts on AI agents, developer tools, open source, and engineering culture. Building in public.

@ShaifulShabuj

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Threads

Day-to-day reflections on software craft, Japanese life, and building with AI as a co-pilot.

@shaifulshabuj

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YouTube

Videos on AI productivity for engineers — tools, workflows, and agentic development in practice.

@aiproductivityforengineers

07. background

Education & Certifications

🎓 Degree

BSc. Computer Science & Engineering

East West University, Bangladesh

Graduated April 2018

🇧🇩🇯🇵 Program

Bangladesh-Japan ICT Engineers Training

B-JET Program

September 2019

🤖 Certifications

LLM & Machine Learning

Udemy / IBM Learning — AI, ML & Project Management

Ongoing

🚗 License

Japanese Driver's License

Japan

May 2021

Language Proficiency

🇯🇵 Japanese JLPT N3

🇬🇧 English Business / Advanced

🇧🇩 Bengali Native

08. let's connect

Get In Touch

Passionate about backend engineering, cloud infrastructure, and AI/ML systems. Always happy to connect with fellow engineers, open-source contributors, and the broader tech community.

GitHub LinkedIn dev.to X / Twitter Threads YouTube

📍 Yokohama, Kanagawa, Japan