Sebastián Carmona Puello

I'm a full-stack developer based in Cartagena, Colombia, working under the brand SebastianDev. Since 2022 I've built and maintained scalable web platforms at Smartinfo SAS using NestJS, PostgreSQL, React and Angular, and I've led full projects end to end under Scrum — scoping the work, coordinating a small team, and owning the result.

Outside my day job I ship and maintain cortex-sync, an open-source CLI published on npm, and I write about the real bugs and security findings from building it on the blog — including a self-audit that found a remote code execution bug in my own tool. I also build workflow automations with n8n and study offensive security basics (nmap, Wireshark) in my own time.

This site — its performance, SEO and agent-readiness work — is itself a live example of what I do: it's a Next.js front end and a NestJS API I designed, built and deploy myself.