Full Stack Software Engineer

I build web applications, end to end.

I'm Harold Velez, a full-stack software engineer. I build responsive, production-grade web applications across the whole stack — from React and Next.js interfaces to the Node, Python, and cloud infrastructure behind them. I care about software that's reliable, maintainable, and genuinely useful to the people who depend on it.

Get in touch → GitHub LinkedIn

7+ yrs: Building production software
Full-stack: Frontend, backend & cloud
React · Node · Python: Core stack

01 Selected work

What I've built

Current

2023 — Present

AI agents / LLMs
Team leadership
Backend · Frontend
Windows · Android
TypeScript · Python

Full Stack Engineer · Automat

For nearly three years I've led teams building AI-powered automation — designing workflows that pair LLMs with reliable, unattended execution across the web, native Windows desktop applications, and real Android devices.

The work runs the full stack and the full range of surfaces: browser automation, desktop-native control, and physical device orchestration, all wired into systems that have to run dependably in production.

Delivered

React
Node.js
REST APIs
SQL

E-commerce platform

Built and shipped features across a mid-scale e-commerce platform — product, cart, and checkout flows focused on performance and a smooth purchase experience.

Delivered

React / Next.js
TypeScript
Data visualization

Cybersecurity UI

Developed the interface for a cybersecurity product, turning dense security data into clear, usable dashboards and workflows.

Delivered

React
TypeScript
REST APIs

Ticketing platform features

Delivered features for a large, high-traffic ticketing platform, working within an established production codebase under real load.

Delivered

Angular / React
Node.js / NestJS
SQL
Third-party APIs

Insurance platform

Built web features for an insurance platform and integrated backend services and third-party APIs into the product.

Delivered

React
Node.js
Databases

Student management apps

Built student management applications supporting administrative and reporting workflows for education.

02 Skills

The stack

Languages

JavaScript TypeScript Python PHP

Frontend

React Tailwind Angular

Backend

Node.js Express NestJS Django

Data & APIs

SQL NoSQL GraphQL REST

Cloud & DevOps

AWS Docker Kubernetes CI/CD

Testing

Playwright Jest Cypress

03 About

How I work

I'm a full-stack software engineer based in Cali, Colombia, with a degree in Systems Engineering from Universidad del Valle. Over 7+ years I've built web applications across a range of domains — e-commerce, ticketing, insurance, cybersecurity, and education.

I like owning problems end to end: understanding the real need, designing a solution, and building something maintainable that holds up in production. I care about clean interfaces, solid backends, and the small details that make software pleasant to use and to work on.

I'm fluent in English and Spanish and enjoy collaborative, communicative teams. Outside of work I'm usually cooking, behind a camera, keeping an aquarium alive, or somewhere near a techno set.

Based in: Cali, Colombia
Role: Full Stack Software Engineer
Education: Systems Engineering · Universidad del Valle
Languages: English · Spanish
Also: Photography · cooking · fishing · gaming

04 Contact

Let's build something that lasts.

I'm open to new opportunities and good conversations — full-stack roles, interesting products, or just talking shop. The fastest way to reach me is email.

harold.velez.zambrano@gmail.com GitHub LinkedIn