Role: Senior Frontend Developer (Contract)Rate: Up to €300 - €400/dayStart: ASAPDuration: Open-endedOverviewWe'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 productionRequirements
- 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 EnglishNice to have
- React and or TypeScript exposure
- Experience mentoring or supporting junior developers
- Involvement in architecture or technical decision-making