I’m Sergio Luis Beleno Diaz, a full stack developer based in Bogota, Colombia. I build and maintain commerce infrastructure: the platforms, integrations, and API layers that sit behind the checkout button.
What I Do
I work as a consultant and engineer at Valtech, where I focus on headless ecommerce, web accessibility, and frontend performance. Over five years I’ve worked with React, Next.js, Node.js, GraphQL, PostgreSQL, VTEX, and Contentful, mostly on projects where the interesting problems are the ones nobody documented.
Before that I trained as a mechatronics engineer at Universidad de Pamplona. I also spent time as volunteer full stack tech lead at Inspiranza, a nonprofit, where I led a migration from WordPress to Next.js and Contentful.
What This Blog Is For
This blog documents what gets learned building commerce infrastructure, specifically the parts that never make it into official documentation. Release notes tell you what changed. They rarely tell you what breaks, why a workaround exists, or what the migration actually cost.
Everything here is written from direct experience. Where I’m uncertain, I say so.
What I Write About
- Compliance and accessibility: WCAG in practice, what audits actually flag, and how accessibility requirements land on engineering teams.
- Frontend: performance work, Core Web Vitals, rendering strategies, and the tradeoffs behind them.
- Ecommerce: headless architectures, platform integrations, and migration work.
- AI tooling: applied AI in real development workflows, including where it helps and where it doesn’t.
Working Together
I take on selected consulting and contract work with remote teams, usually around headless ecommerce builds, accessibility remediation, and frontend performance. If that’s relevant to something you’re working on, the contact page has the details.
Views published here are my own and do not represent any employer or client.