Senior Frontend Engineer, Multi-Brand UI & Design System

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

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.