ToeyAIYU teeprakorn1

Teepakorn Kumvong · Backend & Full-Stack Engineer · Secure Systems · Open Source Developer

👨‍💻 About Me

Teepakorn Kumvong · aka ToeyAIYU · Bangkok, Thailand 🇹🇭

I'm a Computer Science graduate from Rajamangala University of Technology Tawan-Ok (RMUTTO) — currently working as a Backend Developer at S11 Group PCL and founder of MN Lizard Team, an open-source organization building tools like Aiyu Multi-Agent and PromSell POS CE. Focused on backend systems, secure runtime, and developer tooling.

🎓 Education & Background

B.Sc. in Computer Science — RMUTTO, Chakrabongse Bhuvanarth Campus (GPA 3.40)
Focus Areas: Backend Architecture, Full-Stack Development, Secure Systems, AI Runtime
Interests: Developer Tooling, Cloud Computing, Open Source

🎯 Current Focus

🏗️  Working on NestJS + gRPC microservices
🤖  Developing open-source AI agent tools
🦎  Maintaining MN Lizard Team — open-source org
🌱  Advancing Node.js & system design
🔐  Exploring DevSecOps & security hardening
📚  Researching image forgery detection

💼 Professional Experience

Backend Developer — S11 Group PCL | 2026–Present

S11 Group PCL (SET: S11) — A SET-listed financial institution and a leading player in Thailand's motorcycle hire-purchase market, operating nationwide through an extensive dealer network.

Building and maintaining NestJS microservices for internal business operations.

What I Build

Dealer-facing web platform: Angular SPA + Express SSR BFF (HttpOnly cookie sessions, CSRF guard, rate limiting, SSE progress)
RESTful APIs and gRPC microservices with NestJS
Internal service-to-service lookup APIs — API-key auth, gRPC data gateways, graceful degradation, TTL caching
gRPC file-storage service — S3 multipart/presigned uploads, chunked streaming, multi-bucket IAM profiles
Async image pipeline — BullMQ job queue + SSE real-time progress
Authentication & authorization (JWT/JWKS, Keycloak, API key guards, ownership checks)
Legacy system modernization — migrating core business logic to NestJS services
Reverse-engineered an outsourced codebase into an internal technical reference
Authored test plans & service scaffolding standards for internal microservices
Resilience patterns: circuit breaker, saga, distributed locks, single-flight

Measured Impact (load-test benchmarks)

Pre-approve aggregation: p50 −66%, RPS +~200% via parallel orchestration
Contract listing: worst-case page load 250× faster (keyset pagination + caching)
Duplicate-write prevention under multi-replica flood: 15k+ requests → 1 write
~1,900 automated tests across services (unit, e2e, smoke, load harnesses)

Tech Stack

Runtime: Node.js, Bun (package manager & build)
Framework: NestJS, gRPC + Protocol Buffers, Express (SSR/BFF)
Frontend: Angular 19 (Signals), Tailwind CSS, RxJS
Storage: S3-compatible (MinIO/Garage), Redis, BullMQ queues
DevOps: Docker (multi-stage), nginx, GitLab CI/CD
Patterns: Circuit Breaker, Saga, Distributed Locks, BFF, Feature Flags (FeatureHub)
Integration: Legacy enterprise systems via internal gRPC gateways

Source code is proprietary and not publicly available.

Software Engineer Intern — Banzai (Thailand) Co., Ltd. | 2025

Banzai (Thailand) Co., Ltd. — A subsidiary of Banzai, Ltd. (Japan), a specialized trading company for automotive maintenance equipment, inspection tools, and after-sales services across Thailand.

Built a full-stack company website (Company Profile) with React and Express.js, including user management, product catalog, dashboard, and a Markdown-based content system.

What I Built

Full-stack company website with React + Express.js
Authentication & authorization (JWT + bcrypt + cookie-based sessions)
File upload & image processing (multer memory storage + sharp)
Security hardening (helmet, CORS, XSS prevention, rate limiting)
Structured logging with winston (request, security, performance)
SEO optimization (react-helmet-async + react-snap static generation)
Markdown content management (react-markdown with sanitize)
Internal inventory management system aligned with ISO 27001 practices
IoT control programs in Python & C++ for automated device management

Tech Stack

Frontend: React, react-router-dom, axios, react-helmet-async, react-snap
Backend: Express.js, JWT, bcrypt, cookie sessions, nodemailer
Data & Files: MySQL, multer, sharp, file-type (magic bytes)
Security & Ops: helmet, CORS, XSS, rate-limiter, geoip-lite, winston, Swagger

Fieldwork with engineers — machinery installation, inspection, and maintenance at client sites.

Assistant Computer Engineer Intern — V.VATTANA Solution Engineering | 2021

V.VATTANA Solution Engineering Co., Ltd. — An engineering and manufacturing company based in Samut Prakan, specializing in industrial machinery design, PLC automation systems, and technical consulting for the manufacturing sector.

First exposure to industrial IT during vocational studies — assisted senior engineers with PLC programming (ladder logic), C++ embedded board control, and on-site computer maintenance (hardware, OS, network) at client factories.

🦎 MN Lizard Team

Open-source organization building practical software for local businesses and developers.

Founded to share the tools we build with the community. No fixed roadmap — if a project is worth building, we build it.

Featured Projects

Project	Tech	Description
Aiyu Multi-Agent	Node.js, TypeScript	Multi-agent AI runtime with 84+ agents, MCP integration, WebSocket streaming, multi-LLM failover (OpenAI, Claude, Groq, Ollama), and pluggable skill system via npm
PromSell POS CE	Flutter, Dart	Offline-first mobile POS — Clean Architecture + BLoC, Drift SQLite, SQLCipher encryption. Sales, inventory, VAT, split payments, PromptPay QR, day closing, transactional stock integrity, encrypted backups, Thai/English l10n
aiyu-md2pdf	Node.js, TypeScript	Cross-platform CLI converting Markdown → PDF + DOCX via Pandoc/XeLaTeX — Mermaid diagrams, Thai/English support, runs on Linux/macOS/Windows · npm

→ Visit Organization Profile · Contributing Guide

🌐 Side - Open Source

md2pdf-th

Personal open-source project — Markdown-to-PDF engine with Thai-aware typography. Auto-detects Thai text with smart font fallback, supports mixed-language documents, and runs as CLI, library, or NestJS module.

Features: Light/Dark themes, 3 built-in templates (resume, report, invoice), TOC, cover page, watermark, PDF merge, and Docker/Chromium support.

GitHub · npm

💡 Need DOCX output or Mermaid diagrams? See the org variant aiyu-md2pdf — a Pandoc/XeLaTeX-powered cross-platform CLI.

🛠️ Technical Skills

💻 Languages & Frameworks

TypeScript · JavaScript · Python · C++ · SQL · Dart · Java · Kotlin

⚙️ Backend, Frontend & Infrastructure

Category	Technologies
Backend	NestJS, Express.js, gRPC, REST, WebSocket, SSE, BullMQ
Frontend	Angular (Signals), Tailwind CSS, RxJS, React
Databases	MySQL, MariaDB, MS SQL Server, MongoDB, Redis (cache/queues/sessions/pub-sub), Firebase, Drift (SQLite)
Storage	S3 (multipart, presigned URLs), gRPC chunked streaming
Auth	JWT (JWKS), OAuth 2.0, Keycloak, API key guards, BFF cookie sessions
DevOps	Docker, GitLab CI/CD, GitHub Actions, nginx, npm publishing
Observability	OpenTelemetry, Sentry, SigNoz
Cloud	AWS S3, MinIO, Cloudflare CDN

🏗️ Architecture, AI & Security

Area	Skills
AI Runtime	Multi-agent orchestration, LLM failover (OpenAI, Claude, Groq, Ollama), MCP, tool sandboxing
Resilience	Circuit Breaker, Saga, Distributed Locks, Single-Flight, Bulkhead, Rate Limiting, Feature Flags
Testing	Jest, Karma/Jasmine, integration tests, compliance tests, load testing, security test cases
Security	JWT + API key guards, BFF pattern, PII masking, path traversal prevention, magic-byte file validation, XSS/rate limiting
Sec Tools & Network	OWASP ZAP, Burp Suite, Wireshark, Nmap, SQLmap, Kali Linux · OSI, TCP/IP, DNS, VPN, TLS, CIA Triad
Patterns	Facade, Guard, Interceptor, DTO, Repository, Port/Adapter, Orchestrator

🎓 Academic Projects

🎓 BusIT+ (Capstone)	🚀 PM2.5 Monitor	🔮 DuangDee
Student Activity + AI Deepfake — 83.1% acc (10× DenseNet121 ensemble), RBAC, GPS check-in, AES-256	Air Quality + ML Forecast	Fortune-Telling Multi-Platform
`Flutter` `React` `TensorFlow`	`Flutter` `Python` `ML`	`Kotlin` `React` `Firebase`
🔗 Backend · 💻 Web · 📱 Mobile · 🤖 AI	📱 Mobile · 💻 Web · 🔧 API	📱 Android · 💻 Web

🧑‍⚕️ Doctor Mgmt	🧠 Depression Screen	🐟 Betta E-Commerce
Patient-Doctor Appointments	Mental Health AI Screening	Thai Betta Fish Store
`React` `Node.js` `MySQL`	`Kotlin` `Flask` `TensorFlow`	`ASP.NET` `SQL Server`
💻 Frontend · 🔧 Backend	📱 App · 🤖 API	Repo

IoT Mini Farm
Smart Farm Automation
`ESP32` `C++` `Blynk`
🔗 Repo

🏆 Achievements & Highlights

🏅 Achievement	📅 Year	🔗 Link
🔬 Research Paper — Image Forgery Detection (under review)	2025	—
🥇 Gold Medal — OOP Competition — National level, Private Vocational Education Association of Thailand	2021	—

┌──(toeyaiyu㉿github)-[~/profile]
└─$ echo "Thanks for visiting!"

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