Staff Software Engineer, Frontend

Block Labs; Portugal; On-site; EUR 70,000 - 110,000; Full time

Job summary

Block Labs is seeking a senior frontend engineer to own the frontend end-to-end for a multi-brand platform. You will architect, implement, and ship brand-aware routing and theming across a single codebase serving multiple brands.

You will build and own the design system and component library used by engineers, designers, and AI-assisted prototyping. You will ship production features quickly, leveraging AI agents while ensuring quality and performance.

Qualifications

• 8+ years building production consumer-facing web apps.
• Own frontend from brief to production with clear ownership.
• Expert in React, Next.js and modern TypeScript.
• Experience with multi-brand or white-label frontends.
• Built or led design systems and component libraries.
• Strong UI/UX sensibility and attention to detail.
• Comfort working with non-engineers and AI-assisted outputs.
• Proven Core Web Vitals improvements in production.

Responsibilities

• Own the frontend end-to-end for a multi-brand platform.
• Architect, implement, and ship brand-aware routing and theming.
• Build and maintain a design system and shared components.
• Translate prototypes into production features quickly.
• Collaborate with non-engineers using AI tools to drive output.
• Deliver consumer-facing UI with performance and accessibility in mind.
• Advise on UX/product concerns with concrete alternatives.

Skills

React

Next.js

TypeScript

Frontend architecture

Design system

Multi-brand frontend

AI agents usage

Performance & accessibility

Tools

CI/CD

Cloud environments

Job description

About Block Labs

Block Labs is a premier technology studio operating at the bleeding edge of Web3, Artificial Intelligence, and iGaming. We don't just ship features; we engineer high-scale, production-grade platforms that power the next generation of digital products.

We are a collective of senior engineers, product strategists, and builders who refuse to compromise on architecture. Whether we are designing autonomous multi-agent AI systems, building decentralized financial infrastructure, or architecting high-frequency iGaming platforms, our standard is excellence.

We move fast, but we build for the long term. If you are looking to work alongside a team that values deep technical expertise, thoughtful system design, and product ownership, Block Labs is where you belong.

The role

We are building the frontend of a multi-brand consumer platform in React, Next.js and TypeScript: one codebase serving several brands, where launching a brand should be a matter of configuration, not a copy. You will be the most senior frontend engineer in the company and the person the platform's UI depends on.
We don't hire into squads. We work as a small number of very strong individual contributors, each owning a product end to end and shipping with AI agents at a pace that used to take a team. You get an outcome and constraints, not a backlog: you find the decisions nobody has made, scope the work, build it, ship it and stay accountable for how it behaves in production. Product ideas often arrive as working prototypes built with AI tools by people outside engineering. Your job is to steer them into production, not to reject them or rebuild them from zero.

Key Responsibilities:

• Own the frontend end to end: architecture, conventions, quality bar and production behaviour of a multi-brand platform, with no spec handed to you.

• Make adding a brand a configuration change: theming, brand-aware routing and content, and clean boundaries between shared and brand-specific code, all on a live product.

• Build and own the design system and component library that engineers, designers and AI-assisted prototyping all draw from.

• Turn product prototypes into production features fast, and build the workflow and tooling that make this repeatable.

• Ship with AI coding agents every day as your main way of working, with the checks that keep quality high at agent speed, and raise the bar for how others use them.

• Ship consumer-facing UI with real attention to detail, performance and accessibility.

• Take UX and product concerns straight to the people who own the product, with alternatives and working examples, not just objections.

About You:

• 8+ years building production consumer-facing web applications, several of them at Staff or equivalent ownership.

• You have taken a frontend from a rough brief to production and owned it, and you can say exactly what was yours, what was your team's and what was your agents'.

• AI coding agents are how you build, not a helper. You have your own setup and can say precisely where agents make you faster, where they produce plausible but wrong output, and how you catch it.

• Deep expertise in React, Next.js and modern TypeScript, with clear opinions on rendering strategies and when each is the wrong choice.

• Hands-on experience building or re-architecting multi-brand, multi-tenant or white-label frontends.

• You have built or owned a design system and can discuss consistency versus flexibility, adoption and governance.

• Strong UI and UX sensibility: you notice the small things and fix them without being asked.

• Comfortable working with non-engineers who build with AI tools, and you design for their output to be usable.

• Demonstrable Core Web Vitals work in production.

• You thrive with autonomy and light process, and you write clearly. Strong command of written and verbal English.

Nice to have

• Experience with real-time, high-interaction consumer interfaces where latency and feel matter.

• Background in fintech, crypto, real-time gaming and entertainment platforms, or other high-traffic consumer products.

• Tooling, skills or integrations you built so agents work better inside a specific codebase or design system.

• Working knowledge of CI/CD and cloud environments.

What this role is not

• Not a management or lead role. Influence comes from what you ship.

• Not a pure architecture role. You write production code every day.

• Not for someone who wants a team, a backlog or a complete spec before starting.

What kind of culture can I expect?
Mature, mission-driven, and low-ego. We value clarity over noise, outcomes over theatrics, and pace without chaos. If you're one of the smartest minds in your craft and want to build with other experts, you'll feel at home here.