Role: Senior Frontend Developer (Contract) Rate: Up to €300 - €400/day Start: ASAP Duration: Open-ended Overview We’re hiring a Senior Frontend Developer to deliver high-performance, conversion-focused web experiences across customer-facing platforms and internal tools. This is a hands-on contract role with immediate impact, suited to someone who thrives in fast-paced, product-led environments. You’ll work closely with Product, Marketing, and Design to build interfaces that are not only technically strong, but also optimised for user engagement and performance. Responsibilities - Build modern, high-converting user interfaces with strong attention to UX and performance - Develop and maintain frontend code for public websites and internal tools - Ensure full responsiveness and cross-browser compatibility - Integrate frontend components into PHP environments using Twig or similar templating systems - Execute A B testing implementations and optimise based on performance data - Conduct thorough browser and device testing to ensure reliability - Collaborate with Product, Marketing, Design, QA,



and Operations - Maintain code quality through reviews and best practices - Take ownership of features from development through to production Requirements - 5+ years frontend development experience in production environments - Strong HTML5, CSS3, and JavaScript (ES6+) fundamentals - Solid experience with jQuery and working in PHP-based environments - Experience with Twig or similar templating engines - Strong CSS architecture knowledge, including BEM and SASS - Experience with NPM, Yarn, or similar tooling - Proven ability to build from scratch, not purely framework-driven - Experience with A B testing and performance optimisation - Strong debugging and cross-browser testing skills - Experience working independently with high ownership - Hands-on use of AI tools and ability to implement AI-driven features or agents - Conversational Spanish and intermediate English Nice to have - React and or TypeScript exposure - Experience mentoring or supporting junior developers - Involvement in architecture or technical decision-making

📌 Senior Frontend Developer - €300 - €400 A Day (Vitoria-Gasteiz)
🏢 La Fosse
📍 Vitoria-Gasteiz