Frontend Software Engineer - React/JavaScript (m/f/d)

The way SIXT builds software is evolving: engineers turn product problems into clear specifications, direct AI coding agents to build them, and own the quality of what ships. As a Frontend Software Engineer (m/f/d), you will operate at exactly this level - delivering primarily through specification and review, backed by the frontend depth to read, debug, and stand behind every change your agents produce. You will turn ambiguous product problems into testable specifications, run end-to-end agent workflows, and own what reaches production. Sounds like your next challenge? Then apply now and become part of Team Orange as a Frontend Software Engineer (m/f/d) in Lisbon! YOUR ROLE AT SIXT • You turn ambiguous product problems into clear, testable specifications that agents can execute against • You run end-to-end agent workflows to build features, then review the resulting change as a whole - correctness, architectural consistency, and drift • You own what your agents ship to production, debugging to root cause and encoding prevention through tests, rules, or agent constraints • You ship small-to-medium features end-to-end with minimal guidance, including deployment • You build production-quality, reusable React components and integrate reliably with backend and third-party systems • You challenge unclear requirements, weigh business and user trade-offs, and communicate decisions and risks clearly to product and engineering partners YOUR SKILLS MATTER • Education You hold a Bachelor's or Master's degree in Computer Science or a related field, or you have experience with the tools and skills required • Experience You bring 3-6 years of frontend software engineering experience • Hard Skills You have strong React.js and framework-based JavaScript know-how, including component contracts, state management, and rendering and performance behaviour • Know-how You understand how the browser parses, renders, and paints a page, and write semantic, accessible HTML by default • Tools