JJ Teoh

Software Developer

Systems, Infrastructure & Full-Stack Applications

Mechatronics engineer turned software developer. I build reliable systems — from edge device sync engines and financial platforms to compliance infrastructure and developer tooling.

Distributed Systems
Full-Stack
Infrastructure
AI Agents
Desktop Apps
Cross-Platform Mobile

About

I started in mechatronics engineering — designing control systems and working with embedded hardware. That foundation in systems thinking shapes how I approach software: I think in terms of failure modes, data flow, and operational constraints, not just features and frameworks.

Distributed Systems

Building reliable data synchronization, offline-first architectures, and edge computing solutions that work in constrained environments.

Full-Stack Product Engineering

End-to-end application development from database design and API architecture to polished user interfaces and deployment pipelines.

Infrastructure & DevOps

Container orchestration, CI/CD pipelines, monitoring, and the operational tooling that keeps systems running in production.

Featured Projects

Edge Device Sync Engine

IoT Platform

Offline-first bidirectional sync between IoT field devices and cloud infrastructure.

Tauri
TypeScript
SQLite
MQTT
+4 more

Hospitality Management Platform

Enterprise Platform

Unified PMS, POS, and e-invoicing system for hotel operations.

Next.js
NestJS
Electron
PostgreSQL
+5 more

Fitness Coaching Platform

Cross-Platform

Cross-platform coaching tool with web dashboard, mobile app, and native health integrations.

React
Expo
NestJS
PostgreSQL
+5 more

E-Invoicing Compliance SDK

Developer Tool

Published npm SDK for Malaysian e-invoicing with digital signing and rate limiting.

TypeScript
Node.js
Vitest
+1 more

AI Trip Planner

AI / Full-Stack

AI-powered travel itinerary planner with real-time collaboration, expense tracking, and Google Maps integration.

Nuxt
Mastra
TypeScript
PostgreSQL
+2 more

StarNet++ GUI

Desktop App

Cross-platform desktop GUI for astronomical image processing.

Tauri
Vue
Rust
+1 more

Experience

Studio20 logo

Back End Developer

Studio20 · Full-time

Bangsar, Kuala Lumpur · Hybrid

Mar 2024 — Present
  • Built e-invoicing compliance system (MyInvois) with document validation, PKI digital signing, and API integration with LHDN
  • Developed backend services and REST APIs using NestJS with PostgreSQL and MongoDB
  • Implemented role-based access control and multi-tenant data isolation for internal platform
  • Set up CI/CD pipelines and established code review workflows for the backend team
ViTrox Corporation Berhad logo

Software Developer

ViTrox Corporation Berhad · Part-time

Remote

Feb 2024 — Present
  • Maintain and ship features for internal web application used across business units
  • Built cross-platform desktop application for user management using Tauri, Vue, and SQLite
  • Implemented offline-first data handling with background sync for desktop tooling
ViTrox Corporation Berhad logo

Industrial Trainee

ViTrox Corporation Berhad · Internship

Penang, Malaysia · On-site

Oct 2023 — Jan 2024
  • Built full-stack web application for real-time data visualization and IoT device control
  • Implemented frontend with Nuxt 3, Quasar, and Tailwind CSS connected to device APIs
  • Worked directly with hardware teams to integrate embedded communication protocols
i-SURVY SDN BHD logo

Data Entry

i-SURVY SDN BHD · Part-time

Malaysia · Remote

Feb 2022 — Jul 2024
  • Automated report generation workflows using Python scripts and Excel templates
  • Reduced manual data processing time through scripted pipelines

Skills & Technologies

Languages

TypeScript
JavaScript
Rust
Python
SQL

Frontend

Vue
Nuxt
React
Next.js
Expo
Tailwind CSS
Three.js

Backend

Node.js
NestJS
Elysia.js
Hono
Mastra
REST
GraphQL
WebSocket

Databases

PostgreSQL
SQLite
Redis
MongoDB

Infrastructure & DevOps

Docker
CI/CD
Linux
Nginx
GitHub Actions

Tools & Practices

Git
TDD
Vitest
Jest
Playwright
Monorepos
Tauri
MQTT
PKI/X.509

Architecture & System Design

Simplified views of system architectures I've designed and built.

Edge Sync Architecture

Offline-first bidirectional sync with ElectricSQL between field devices and cloud

CLIENT SYNC LAYER BACKEND Tauri Desktop Apps Vi2 / V-Dosing SQLite PWA Companion MongoDB MQTT Broker ElectricSQL Offline-first sync Hono API Server PostgreSQL writes subscriptions telemetry REST syncSynchronousBidirectional sync

Multi-App Hospitality Platform

Monorepo with shared typed package connecting PMS, POS, and e-invoicing apps

FRONTEND SHARED BACKEND PMS Web App Next.js POS Desktop Electron E-Invoice Portal Next.js Shared TypeScript Package Types, validators, utilities NestJS API REST + WebSocket PostgreSQL SuperTokens Auth importstyped API calls WebSocket auth SynchronousReal-time (WebSocket)

Multi-Agent AI Analytics

Specialized AI agents with MCP tool integration for financial data analysis

FRONTEND AI ORCHESTRATION DATA & INTEGRATIONS Chat UI Nuxt Mastra Framework Orchestrator AI AGENTS Financial Advisor Account Assistant Contact Manager MCP Server Tool bridge Accounting API PostgreSQL + pgvector SSE streamtool calls semantic search SynchronousStreaming / asyncKey component
GitHub contribution grid snake animation

Get in touch!

Have a project in mind, want to collaborate, or just say hello? Drop me a message.