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