Senior Frontend Engineer

We are working with a digital challenger in the energy market, making energy different for a young, urban, and digital generation. They provide private households and small to medium\-sized businesses with energy from sustainable sources, offering customized electricity and gas tariffs, optionally combined with lifestyle products, all fully digital with a top\-rated energy app. The Role * Develop and continuously improve customer\-facing experiences across web and mobile platforms * Focus on usability, performance, and scalability to create an engaging end\-to\-end energy experience * Build and maintain key customer journeys including login, account management, billing, payments, and self\-service features * Develop with Next.js / React and TypeScript using a component\-oriented approach * Integrate frontend applications with API\-driven backends (GraphQL / REST) * Collaborate closely with UX/UI Design, Backend, QA, and Platform Teams in Agile/Scrum setups What You'll Need * Several years of experience developing production\-ready frontend applications with React / Next.js and TypeScript * Strong fundamentals in frontend development: component architecture, performance optimization, accessibility, and modern CSS * AI\-Native Developer Mindset with experience in agent\-driven workflows using tools like Claude Code, Cursor (Composer), or Windsurf (Cascade) * Experience with API\-first platforms and authentication flows * Pragmatic approach to testing and confident working in CI/CD driven teams * Strong communication skills in German and English and a distinct ownership mindset What's On Offer * A highly motivated team with flat hierarchies and short communication paths * Workplace in the heart of Cologne with hybrid work options * Performance\-based pay and 30 days of annual leave * Subsidized job ticket and free parking Apply via Haystack today!