Engineering Lead · Barcelona · Remote

Sergi
Meseguer

I build the engineering foundations and systems that turn ideas into scalable products.

20+
years building digital systems that grow with the businesses behind them
30+
markets served through platform-scale systems
25+
engineers led or mentored across teams in 4 continents
15+
years delivering complex products remotely
41.3874, 2.1686 · BCN

Manifesto

Engineering as
intentional craft

The best engineering decisions aren't the cleverest ones. They're the ones that move a product forward, reduce the burden on the team, and create something the next developer can understand, extend, and trust.

I work where engineering, leadership, and delivery meet. Not as a generalist — as someone who holds all three together so the product can grow without fracturing.

The AI workflow took four years to figure out. Features need a spec precise enough to execute. Fixes get prompted. Documentation gets generated. What AI can't do is decide what matters, hold the architecture together, or make the call when there's no correct answer. Judgment about what to build, how to structure it, and when the spec is wrong — that stays mine.

  1. Delivery is the product. A system that can't ship reliably is just expensive debt. Velocity and quality are not opposites.

  2. Teams are the multiplier. The best architecture isn't the most elegant — it's the one that lets people work in parallel without stepping on each other.

  3. Design and engineering share a grammar. Tokens, components, and systems work when both sides speak the same language.

  4. Every decision is a bet. I place mine on long-term maintainability over short-term impressiveness.

  5. The interface with AI is a spec, not a prompt. The discipline hasn't changed: architectural thinking, system clarity, specs that an AI can execute end-to-end — these are becoming more valuable, not less. That's where I'm putting my attention.

Experience

Hanzo Studio
—

A decade of engineering leadership across some of the world's most demanding digital products. Organizations across Europe, Asia, the Middle East, and North America — spanning hospitality, finance, travel, and insurance.

Much of my work happens at the intersection of engineering, product, and design — helping teams converge on systems that scale both technically and organizationally. Many of the systems I helped design became shared foundations reused across multiple products and teams. Over the last four years, AI has become part of the delivery workflow, changing how work is executed without changing the underlying engineering principles required.

RBA Holding Editorial
—

I worked at the intersection of editorial, technology, and development teams during a period of rapid digital expansion for the group.

The role included product planning, vendor coordination, budget oversight, and technical decision support for several digital publications — including the Spanish website for National Geographic.

Independent Engineering Work
—
—

Before and after my time at RBA, I worked independently building complete digital products — from interface design to backend systems and CMS-driven platforms.

This was the early web era: full sites, database-backed applications, and even CD-ROM software, when distribution still happened on discs. Working end-to-end meant understanding not just how interfaces looked, but how the entire system was structured, deployed, and maintained.

Even in this early phase of the web, I focused on web standards, accessibility, semantic markup, and progressive enhancement — long before they became common practice.

Selected Projects

Work that changed
how all these businesses run

Telefonica · Melia Hotels · Mapfre · Pull and Bear · Standard Chartered · BBVA · Santander · Virgin Money · Amazon Business · Dunia / Deem · Air Europa · Atletico de Madrid · Vogue · Domestika · National Geographic · MTV

Telefónica

Telefónica 100 — centenary experience

A 3D world where a hundred years meets generative AI.

Built a high-complexity 3D web environment to celebrate Telefónica's centenary — including a media archive spanning 100 years of content with search, categorisation, and an API we helped design and shape. Alongside the archive, a generative AI integration lets visitors leave a wish for the future and receive an AI-generated image in response. The technical challenge was holding all of it together at the visual and interactive scale a global centenary campaign demands.

Work delivered at Hanzo has been recognised with Webby, Red Dot, Laus, and European Design awards.

Meliá Hotels

Multi-brand platform at hospitality scale

One system. Seven global brands. Zero duplication.

Built the architecture that lets seven distinct hotel brands share a single component foundation while maintaining completely independent visual identities. Each brand gets its own theme — the business gets a single codebase to maintain and evolve.

Launching a new brand theme went from months of development to weeks. The business gained the flexibility to acquire and onboard new brands without proportional engineering cost.

Work delivered at Hanzo has been recognised with Red Dot award.

Standard Chartered

Forms at market scale

From weeks to days across 30+ markets.

Led a team of 12 to build a form generation platform that automated the bank's digital transformation across global markets. What previously required bespoke development per country became a configurable, testable pipeline.

Hundreds of forms delivered in days instead of weeks. Testing automation cut UAT cycles and regression effort dramatically — directly reducing cost and time-to-market.

Deem

UI library + onboarding engine

Consistent product experience at every touchpoint.

Designed a unified component system that served both the product interface and a client-facing onboarding tool — allowing the business to configure and deploy custom onboarding flows without engineering involvement for each iteration.

Business teams gained autonomy over onboarding flows. Engineering focused on capability, not repetition.

Work delivered at Hanzo has been recognised with a Laus award.

Labs

Personal projects and
ongoing experiments

I build tools I want to use. Firmware, hardware, automation, infrastructure — and increasingly, full products built through spec-driven AI development. Everything here is built in public and used in daily workflows.

Pi Subagents

An extension for Pi that turns AI-assisted work into a deliberate loop: scout a codebase, agree on an interactive plan, then build and validate against the resulting spec. Built around a simple belief: the interface with AI is a spec, not a prompt.

View on GitHub

AI agent sandbox

A Docker-based sandbox that runs AI coding agents with no git, no SSH, and access only to the directories they need. Built because permission prompts aren't real protection — you end up accepting everything by reflex, and that's not a decision, it's fatigue.pi and opencodeship built-in; adding any other agent takes editing three templates and running a single command.

View on GitHub

Spec-Driven Development with AI

An ongoing research practice: building complete fullstack applications through precise specs fed to AI — sometimes working across unfamiliar languages or stacks. A recent example: a full Python web app for managing a music collection, with CSV import, Last.fm API integration, and a custom scraper — built across two evenings with zero prior Python knowledge. The methodology is the experiment. Some projects are public on GitHub.

View on GitHub

Split Keyboard Ecosystem

Open-sourced PCB + QMK firmware for a 34-key split keyboard and a 12-key dual-encoder pad used for Figma and NeoVim shortcuts.

View on GitHub

Keyboard Layer Automation

Open-sourced Node.js utility to switch keyboard layers programmatically based on active workflows.

View on GitHub

Telescope Docker Commands Picker

NeoVim extension for Telescope that provides a fast command picker for common Docker workflows inside the editor.

View on GitHub

macOS Calendar Events Binary

Swift script compiled into a binary that displays upcoming Calendar events, designed for SketchyBar integration and reusable elsewhere. Uses EventKit to avoid common macOS TCC permission issues seen in other tools.

View on GitHub

Electronics and DIY HiFi

Ongoing electronics builds, including Arduino programming and DIY HiFi audio experiments.

Home Lab Infrastructure

Ansible-orchestrated Docker services, VLAN-aware firewall networking, and external access via reverse proxy and VPN. Home Assistant dashboards in Grafana powered by sensor data and syslogs.

Contact

I'm looking for the next team where I can help shape architecture, engineering culture, and product delivery.I enjoy conversations about product thinking, AI-assisted development workflows, and the craft of building teams and systems that ship well. I also experiment with hardware and personal tools on the side. Barcelona-based, working remotely across time zones.

Much of the work is deciding what matters.
Let's talk.