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

Every SIXT rental starts on the web — search, offer, checkout — a funnel that serves millions of customers across 110+ countries. How we build it has changed: coding was never the bottleneck, judgment is. Engineers here turn ambiguous product problems into specifications precise enough for AI agents to execute, drive those agents in small, verifiable steps, and personally own what reaches production — backed by the technical depth to read, debug, and stand behind every change. It's a different kind of engineering, and we're not done shaping it. Join Team Orange and help shape how it gets built. YOUR ROLE AT SIXT Turn ambiguous product problems into clear, testable specifications — success criteria and edge cases spelled out — that agents can execute against Work with AI tools, adapt and improve agentic ecosystem by building strong guardrails and processes that keeps the product stable Drive agents in small, verifiable steps, correcting and re-steering when the output drifts from intent Own what your agents ship to production: debug to root cause, and encode prevention — a test, a lint rule, an agent constraint — so the same issue is caught automatically next time Ship medium-to-complex features end-to-end with minimal guidance Deliver production-quality, reusable React components and integrate reliably with backend   YOUR SKILLS MATTER Bachelor's/Master's in Computer Science or a related field, with 3–6 years of frontend software engineering experience Strong React.js — component contracts, state management, rendering/performance behavior — with a solid grasp of how the browser parses, renders, and paints a page, enough to guide AI toward semantic, accessible HTML. Depth is important: it lets you review and trust agent output Proficient with HTML, CSS, JSON, build tools, and Git, with excellent debugging skills. Treats cross-browser compatibility and measurable frontend performance as defaults, not afterthoughts Sets up agentic workflows: delegates well-scoped tasks to AI agents, reviews output critically for correctness, standards, and architectural drift, recognises low-value output and course-corrects before it merges — and can explain any of it Shares agent workflows to speed up the team and onboard them on good AI practices, discuss trade-offs in reliability, performance, and correctness with the team Good problem-solving and communication with strong ownership across execution and delivery: collaborates with Product/peers, challenges unclear framing, builds judgment on architecture and outcomes   WHAT WE OFFER A Global Tech Hub in Lisbon Join a thriving international tech community and work alongside engineers, product experts, and business teams who turn ideas into real impact. Our hubs at Factory Lisboa in Beato and ARTs Lisboa in Parque das Nações are where great tech gets built Learning & Knowledge Exchange Level up through regular events with internal and external speakers. We value curiosity,…