Joined the Growth team, which meant living in the sales funnel and the experiments that shape it — landing through checkout, several A/B tests a week, the platform growing from one brand and a couple of products to three brands and dozens. The architecture work ran in parallel: I co-led the migration from a Nuxt 2 monolith to a React and Next.js monorepo, bootstrapped the company's first design system, and put observability and CI/CD on real footing with Datadog and a testing culture the team actually uses. I was early to MCP and agentic workflows too — partly curiosity, partly because it's clearly where the work is going.
Barcelona · 41.38° N — Available now
Àlex
Castelo
Senior Frontend Engineer
React and Next.js engineer who also speaks fluent Vue and Nuxt. I care about frontend architecture, the technical culture around it, and the systems that connect them.
Frontend engineer with seven years in the industry, based in Barcelona — most of it deep in React and Next.js, with a Vue and Nuxt past that still shapes how I think about components. 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 everything I haven't figured out yet.
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. Most of that work lately has been in React and Next.js; the Vue and Nuxt years before it still inform how I reason about state and structure.
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.
Selected work
Stepped into a lead role on the customer team while staying close to the code. The concrete work was launching Holaluz's native customer app from scratch and the self-service area around it, aimed at growing the solar business and keeping customers around. The rest of the job was quieter: how the team communicated, how engineering decisions connected back to product, how to be a good teammate to people I learned from every day. 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. 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.
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.