Hello

I'm Xavier, a technologist and builder based in San Juan.

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I'm a technologist who loves to build things that matter. I have a deep belief that the best products sit at the intersection of engineering rigour and thoughtful design — and I've spent my career trying to prove that out.

I obsess over developer experience, systems thinking, and making complex things feel simple. Whether I'm writing infrastructure, designing an API, or shipping a product, I try to do it with the same care.

Outside of work I write here, take photos on film and digital, and collect more keyboards than I can justify.

Work

I run Ikarolabs, a small studio where I take on select product and engineering work — from early architecture to shipped features.

Before that I spent several years in the industry learning how software gets built at scale: what survives contact with users, what collapses under its own weight, and how teams make the difference.

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  • IkarolabsFounder & CTO
    Now2022–now
  • Placeholder CorpSenior Engineer
    2019–2022
  • Startup IncFull-Stack Developer
    2017–2019

I tend to thrive in environments where there's real ownership and a high bar for craft. I'm equally comfortable deep in an architecture decision or pairing on a tricky bug.

Elsewhere

I'm @xaviercastillo on most sites. Find me here:

This site

I've been publishing here since 2025. Everything is designed and coded by me — no themes, no templates. Written on a MacBook Pro, committed with Claude Code.

  • Built with Next.js, hosted on Vercel.
  • Content pipeline via Content Collections — articles are MDX files in git.
  • Styled with Tailwind CSS v4. Type set in Lora (serif) and Geist (sans).
  • Dark mode is actually a warm dim mode — easier on the eyes than pure black.

Read the journal to see how the thinking behind this place has evolved.