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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # FrontEnd Developer - **Company:** Número De - **Location:** Madrid, Spain - **Contract:** Permanent contract - **Skills:** HTML, Web Accessibility, Application Performance Management, Browser Compatibility, Cascading Style Sheets (CSS), Information Systems, Software Debugging, Software Design Patterns, Web Development, Design of User Interfaces, Performance Tuning, Next.js, Responsive Web Design, TypeScript, Web Applications, ReactJS, Git Flow, Information Technology, Browser Testing, Front End Software Development - **Published:** September 6, 2026 - **Apply:** https://www.adzuna.es/contact-us.html ## About the Role + 5+ years of professional experience in front-end development, with proven experience delivering production web applications. + Deep proficiency in HTML, CSS, and TypeScript. + Extensive hands-on experience with React, including complex state management and front-end architecture. + Strong knowledge of Git workflows, branching strategies, and collaborative development practices. + Demonstrated ability in browser testing, debugging, troubleshooting, and performance optimization. + Solid understanding of the complete web development lifecycle, from design and development through deployment. + Advanced knowledge of UI/UX principles, design patterns, responsive design, and web accessibility considerations. + Solid understanding of SEO best practices for modern web applications. + Strong leadership, mentoring, analytical, multitasking, and problem-solving skills. + Excellent communication and stakeholder management abilities, with the confidence to work effectively with both technical and non-technical audiences. + Ability to work across multiple projects in a fast-paced environment while remaining organized, dependable, and deadline-oriented. + Intermediate to fluent spoken English and fluent written English. + Professional experience with Next.js is considered an advantage. + Experience with additional front-end frameworks and content management systems (CMS) is a plus. + A Bachelor's degree or equivalent professional experience in Computer Science, Information Systems, Business Administration, or a related field is desirable. ## Description As a Senior Front-end Developer, you will lead the development of high-quality, responsive, and performant web experiences within a collaborative, client-focused environment. You will translate technical and business requirements into intuitive digital solutions across desktop and mobile. The role combines hands-on development with technical leadership, mentoring, and stakeholder collaboration. You will work extensively with TypeScript, HTML, CSS, and React while helping drive modern development standards and best practices. Your expertise will contribute to scalable architectures, polished user experiences, and reliable application performance. This is an opportunity to influence both technical direction and the quality of digital products delivered to clients. Accountabilities + Lead the design and implementation of high-quality front-end solutions aligned with technical and business requirements. + Collaborate closely with clients, team members, stakeholders, and leadership to deliver effective digital experiences. + Develop tested, documented, clean, and efficient TypeScript, HTML, and CSS code. + Build responsive, cross-browser-compatible applications optimized for both desktop and mobile environments. + Develop interactive prototypes to explore and validate innovative UI solutions. + Drive the adoption of modern development standards, tools, frameworks, and engineering practices. + Apply UX, branding, responsive design, and SEO principles throughout the development lifecycle. + Conduct browser testing, debugging, and performance optimization to ensure reliable and performant applications. + Produce detailed technical documentation and test plans while maintaining high-quality codebases. + Mentor junior and mid-level developers, encouraging best practices, knowledge sharing, and professional growth. + Build trusted relationships with clients, colleagues, and stakeholders while serving as a reliable technical advisor. + Manage multiple projects and priorities effectively while consistently meeting agreed deadlines and commitments. + Provide code samples as part of the application process, with one repository that best represents your relevant work. ## Related Videos - [GraphQL + Apollo + Next.js: A Lovely Trio](https://www.wearedevelopers.com/videos/311-graphql-apollo-next-js-a-lovely-trio) - [Watch Tests Go Brrrr! : Getting Started with Cypress in ReactJS](https://www.wearedevelopers.com/videos/282-watch-tests-go-brrrr-getting-started-with-cypress-in-reactjs) - [The Resilience of the World Wide Web](https://www.wearedevelopers.com/videos/1281-the-resilience-of-the-world-wide-web) - [But, you're not Facebook](https://www.wearedevelopers.com/videos/378-but-you-re-not-facebook) - [From Zero to Hero: NextJS 13 and Tailwind CSS for Beginners](https://www.wearedevelopers.com/videos/766-from-zero-to-hero-nextjs-13-and-tailwind-css-for-beginners) - [To New Frontiers: The Future of Frontend Development](https://www.wearedevelopers.com/videos/404-to-new-frontiers-the-future-of-frontend-development) ## Related Articles - [The Best 7 Frontend Frameworks for Developers in 2025](https://www.wearedevelopers.com/magazine/400-the-best-7-frontend-frameworks-for-developers-in-2025) - [What’s the Difference Between Frontend and Backend Development?](https://www.wearedevelopers.com/magazine/240-what-s-the-difference-between-frontend-and-backend-development) - [What is a web developer?](https://www.wearedevelopers.com/magazine/18-what-is-a-web-developer) - [16 Best Free React UI Libraries in 2025](https://www.wearedevelopers.com/magazine/148-16-best-free-react-ui-libraries-in-2025) - [25 Essential Tools for Front End Developers](https://www.wearedevelopers.com/magazine/210-25-essential-tools-for-front-end-developers) - [Frontend Developer Salary in The UK](https://www.wearedevelopers.com/magazine/233-frontend-developer-salary-in-the-uk)