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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Frontend Engineer - **Company:** Número De - **Location:** Madrid, Spain (Remote available) - **Salary:** €89,000.0 - €127,000.0 - **Contract:** Permanent contract - **Skills:** JavaScript (Programming Language), Agile Methodology, Cascading Style Sheets (CSS), Software as a Service, Software Quality, Code Review, Cursor (Graphical User Interface Elements), Performance Tuning, E2e Testing, Software Tools, Responsive Web Design, TypeScript, Web Applications, Web Usability, GitHub Copilot, ReactJS, Cypress (Programming Language), Pixel Perfect, Firebase, Backend, Webpack, Git Flow, Material UI, Playwright, Build Tools, Figma, Graphql, Front End Software Development, React Redux, React Testing Library, Restful APIs, Service Stack - **Published:** August 8, 2026 - **Apply:** https://www.adzuna.es/contact-us.html ## About the Role + Minimum 5 years of professional experience building production-grade React applications. + Strong expertise in TypeScript, React, Material UI (v5+), Redux Toolkit, and RTK Query. + Advanced knowledge of modern CSS, including Flexbox, Grid, responsive design, and mobile-first development principles. + Experience developing complex forms with React Hook Form. + Proven experience with frontend testing using Jest, React Testing Library, Cypress, Playwright, or similar frameworks. + Strong understanding of performance optimization techniques, including lazy loading, code splitting, and application profiling. + Experience working from Figma designs and delivering pixel-perfect implementations. + Familiarity with Agile development practices, Git-based workflows, and modern frontend build tools such as Vite or Webpack. + Comfortable using AI-assisted development tools such as Claude, Claude Code, Cursor, or GitHub Copilot within daily engineering workflows. + Excellent written English communication skills and the ability to work independently in a remote, asynchronous environment. + Availability to consistently overlap with U.S. business hours. + Experience with Firebase, GraphQL, REST APIs, mapping libraries, micro-frontends, or B2B SaaS products is considered an advantage. ## Description This fully remote contract opportunity is designed for an experienced frontend engineer who thrives in fast-paced product environments and enjoys building high-quality web applications from the ground up. You will play a key role in delivering intuitive, production-ready user interfaces while collaborating closely with product, design, and backend engineering teams. Working in an AI-assisted development environment, you will leverage modern engineering tools to accelerate delivery while maintaining exceptional standards for code quality, performance, and usability. This role offers significant ownership across the entire feature lifecycle, enabling you to influence frontend architecture, improve engineering practices, and contribute to a rapidly evolving SaaS platform. Accountabilities + Design, develop, and deliver responsive, pixel-perfect user interfaces using React, TypeScript, and Material UI. + Own frontend features from design handoff through implementation, testing, deployment, and continuous improvement. + Build complex, validated forms and deliver seamless user experiences across desktop, tablet, and mobile devices. + Develop and maintain automated unit, integration, and end-to-end tests to ensure application reliability. + Optimize frontend performance, accessibility, responsiveness, and Core Web Vitals. + Collaborate closely with product managers, designers, and backend engineers to deliver high-quality features. + Participate in code reviews, mentor other engineers, and contribute to frontend best practices and architecture decisions. + Utilize AI-assisted development tools responsibly to improve productivity while reviewing and validating generated code. + Help evolve the frontend technology stack, component library, design system, and TypeScript adoption. ## Related Videos - [Boost Productivity with AI: Figma & Playwright MCP Workflows - Aris Markogiannakis](https://www.wearedevelopers.com/videos/1768-boost-productivity-with-ai-figma-playwright-mcp-workflows-aris-markogiannakis) - [Putting the Graph In GraphQL With The Neo4j GraphQL Library](https://www.wearedevelopers.com/videos/257-putting-the-graph-in-graphql-with-the-neo4j-graphql-library) - [Micro Frontends with Module Federation: Why and How?](https://www.wearedevelopers.com/videos/165-micro-frontends-with-module-federation-why-and-how) - [The Pragmatic Architect: Balancing Necessity vs. Sufficiency in React Systems](https://www.wearedevelopers.com/videos/2101-the-pragmatic-architect-balancing-necessity-vs-sufficiency-in-react-systems) - [Native Federation: The Future of Micro Frontends and Plugin-Systems in Angular](https://www.wearedevelopers.com/videos/1018-native-federation-the-future-of-micro-frontends-and-plugin-systems-in-angular) - [GraphQL + Apollo + Next.js: A Lovely Trio](https://www.wearedevelopers.com/videos/311-graphql-apollo-next-js-a-lovely-trio) ## Related Articles - [16 Best Free React UI Libraries in 2025](https://www.wearedevelopers.com/magazine/148-16-best-free-react-ui-libraries-in-2025) - [The Best 7 Frontend Frameworks for Developers in 2025](https://www.wearedevelopers.com/magazine/400-the-best-7-frontend-frameworks-for-developers-in-2025) - [React Developer Salary [2023]](https://www.wearedevelopers.com/magazine/198-react-developer-salary-2023) - [Fully Remote Software Engineer Jobs](https://www.wearedevelopers.com/magazine/447-fully-remote-software-engineer-jobs) - [Dev Digest 133 - Back to Front](https://www.wearedevelopers.com/magazine/474-dev-digest-133-back-to-front) - [Frontend Developer Salary in The UK](https://www.wearedevelopers.com/magazine/233-frontend-developer-salary-in-the-uk)