Full-stack engineer · Systems integration

I build the software businesses run on.

Dashboards, portals, and internal tools — plus the harder work of connecting your business systems to the equipment on the floor. One person, from first plan to live deployment.

Business systemsSAP · ERP · databases
IntegrationI build this layer
Plant floorSCADA · PLC · sensors

Client work

Shown sanitized
Integration · .NET

Factory-to-accounting bridge

Connected a production line directly to the accounting system, so every batch run is recorded automatically instead of typed in twice.

C# / .NETSAP Business OneSCADA dataMongoDB
Web app · Next.js

IT operations platform

Helpdesk ticketing, asset tracking, and a staff directory that keeps itself current by syncing with the organization's Microsoft accounts.

Next.jsPrismaMicrosoft GraphDocker
Dashboard · React

Nationwide maintenance dashboard

A single view of maintenance activity across many sites — work orders, status, and performance rolled up for management.

ReactNodeMongoDBCharts
Web app · NestJS

Certification portal

Submitting, reviewing, and approving certifications, with separate access levels for applicants, reviewers, and admins.

NestJSNext.jsRole-based access
Web app · Forms

Forms & workflow tool

Custom digital forms replacing paper — submissions routed for review and approval, with records kept in one place.

WebApps ScriptWorkflow
Tooling · Automation

Equipment backup utility

Automated backups of industrial controller configurations, so plant equipment settings are never lost.

AutomationPLCScheduling

Personal projects

Built independently
Blockchain · Web

Blockchain e-voting

A voting system where every ballot is recorded on a blockchain — tamper-evident, auditable, and transparent by design.

SolidityWeb3Smart contracts
Mobile · Kotlin

Personal finance app

A native Android app for tracking spending and budgets — fast, offline-capable, built with modern Android tooling.

KotlinJetpack ComposeAndroid
Python · Finance

Trading & backtesting system

An honest backtesting engine and signal generator for stocks and forex, with guided setup and multiple strategies.

PythonBacktestingCLI
Creative · Web

Y2K photobooth

A playful, retro-styled web photobooth — a change of pace that shows range beyond dashboards and integrations.

JavaScriptCanvasWeb

About

Jason Guijo
FocusWeb + integration
WorksSolo, end-to-end
AvailabilityRemote
BasedPhilippines

I'm a full-stack engineer who ships complete systems solo — from the first conversation to the deployed product. Web apps and dashboards are the core of what I do.

What sets me apart: I also do the integration work most developers avoid — wiring business software like SAP to live equipment on the factory floor. It's rare, it's high-stakes, and it's where I do my best work.

Tech stack

Tools I build with
Frontend
Next.js
React
TypeScript
Tailwind CSS
Backend
NestJS
Node.js
.NET / C#
Prisma
Mobile
Kotlin
Android
Jetpack Compose
Data & Blockchain
Python
MongoDB
PostgreSQL
Solidity
Ethereum
Integration & DevOps
SAP Business One
Docker

+ SCADA · PLC industrial systems · Microsoft Graph

Have a system that needs building?

Tell me the problem. I'll tell you honestly if I'm the right person to solve it.