Joined with a brief to push both the architecture and the engineering culture forward. Co-led the migration from a Nuxt 2 monolith to a Next.js monorepo, bootstrapped the company's first design system, and put observability on real footing with Datadog. Spent the last year building the CI/CD discipline and testing habits the team actually uses day to day, and was early to experimenting with MCP and agentic workflows — partly out of curiosity, partly because it's clearly where the work is going.
Barcelona · 41.38° N — Available May 2026
Àlex
Castelo
Senior Software Engineer
Frontend architecture, technical culture, and the systems that connect them.
Frontend engineer with seven years in the industry, based in Barcelona. I care about how teams build as much as what they build — the architecture, the rituals, the small habits that compound.
I'm interested in code, systems, AI, and roughly everything I haven't figured out yet.
01
How I think
I've spent the last seven years writing frontend code and slowly figuring out that the code is rarely the hard part. The hard part is the team around it — how decisions get made, how context travels, how a codebase stays honest as it grows. I try to be useful on both sides of that line.
Technical leadership, to me, is a tool — not a title. Sometimes it means pairing with a junior on a tricky migration. Sometimes it means writing the RFC nobody wants to write, or sitting in the meeting where the real decision actually gets made. The point is to multiply what the team can do, not to collect the credit.
I do my best work remote-first, on a product I believe in, with people who are genuinely curious about the craft. Lately I've been spending a lot of time thinking about what AI changes about all of this — the workflows, the leverage, what the next ten years of engineering actually looks like up close.
02
Selected work
Stepped into a lead role while staying close to the code. The job was less about pushing pixels and more about pushing on the conditions around them: how the team communicated, how engineering decisions connected back to product, how to be a good teammate to people who were better at their craft than I'd ever be. A year that taught me a lot about restraint.
Joined as a frontend developer working in Vue and TypeScript. Contributed to the in-house design system, the team's Storybook practice, and the general slow work of raising the testing and automation floor. A formative few years for understanding how an engineering org actually behaves under load — and how much of it comes down to the basics, done consistently.
Started in tech support and ended up running infrastructure migrations and SSP/DSP integrations across teams. Not a glamorous role, but the one that taught me the most about how technology actually meets business outcomes — and that most of engineering is, in the end, communication.
Earlier roles in support and operations. The foundation — how to listen to a problem before trying to solve it.
03
Get in touch
I'm open to senior engineering roles — full remote, technical leadership as a tool not a title, at companies building something that matters to them.
Mission alignment matters to me, so I tend not to engage with opportunities in gambling, adult content, or anything that profits from making people worse off. Otherwise, I'm easy to reach.