Frontend Engineer

React Bun Webpack Playwright Descripción del empleo 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., As a Senior Frontend Engineer, you will help build and ship high-performance, modular and visually distinct interfaces across our multi-tenant platforms. You will work within cross-functional teams of engineers, product managers and designers, owning the frontend layer that powers multiple white-labeled experiences for partner brands. This is a hands-on role with significant influence over our templating strategy, micro-frontend architecture, performance budgets and frontend tooling. You will move quickly, leveraging modern AI-assisted development workflows to ship production-quality code at a pace that matches our delivery ambitions. Key Responsibilities

• Rebuild an existing customer-facing product UI and launch a new branded experience for an incoming partner, both running on shared multi-tenant foundations
• Design and own the templating and theming system that lets us spin up differentiated UIs per tenant without duplicating codebases
• Architect and maintain micro-frontend boundaries across our platforms so teams can ship independently while keeping shared user journeys consistent
• Hit and defend strict Core Web Vitals targets (LCP, INP, CLS), enforcing performance budgets and shipping measurable optimisations
• Build, maintain and refactor modular Next.js and React interfaces with reusability and tenant configurability as first-class concerns
• Use AI coding tools (Cursor, Claude Code or equivalent) as a core part of your daily workflow to accelerate scaffolding, refactoring, test generation and overall shipping velocity
• Collaborate with product and backend engineers to define API contracts, feature behaviour and tenant-specific configuration
• Advocate for clean, testable and maintainable code through peer reviews, documentation and a strong shared design system
• Work within a modern CI/CD pipeline to ship features safely across multiple tenant environments

Block Labs is seeking a Senior Frontend Engineer in Málaga, Spain. In this role, you'll leverage your 5+ years of experience in frontend engineering to rebuild UIs and develop modular interfaces across multi-tenant platforms. You must possess deep expertise in React, TypeScript, and micro-frontend architectures, with a strong focus on performance metrics and modern development tools. Join a mature, mission-driven culture committed to delivering high-quality digital products., * 5+ years of frontend engineering experience building production-grade applications.

• Deep expertise in React and modern TypeScript for rendering strategies.
• Solid track record with micro-frontend architectures and Core Web Vitals., * Rebuild customer-facing product UI and launch new branded experiences.
• Design and own templating system for differentiated UIs.
• Maintain micro-frontend boundaries for consistent user journeys.

Conocimientos

Frontend engineering experience Expertise in React and modern TypeScript Experience with micro-frontend architectures Fluency with AI-assisted development tools Knowledge of modern build tools Strong command of English, * You have 5+ years of frontend engineering experience building production-grade, consumer-facing web applications

• Deep expertise in React and modern TypeScript, with strong opinions on rendering strategies (SSR, SSG, ISR, React Server Components) and when to apply each
• Experience with Next.js is a plus
• Hands-on experience designing or maintaining multi-tenant frontends, including theming, templating, white-labeling or partner-configurable UI
• Solid track record working with micro-frontend architectures (module federation, monorepos, independent deployables) and a clear understanding of the trade-offs
• Demonstrable experience hitting tight Core Web Vitals targets in real production environments: profiling LCP, optimising critical rendering paths, image and font strategies, code splitting, edge caching and server components
• Fluency with AI-assisted development tools (Cursor, Claude Code, Copilot) and a clear point of view on how to use them to ship faster without compromising quality
• Comfortable with modern build tools (Bun, Vite, Webpack, Turbopack) and testing frameworks (Playwright, Cypress, Vitest)
• Working knowledge of DevOps practices and containerisation in cloud environments
• Strong command of both verbal and written English
• Background in fintech, DeFi, real-time gaming and entertainment platforms or other high-traffic consumer products is a strong plus