(Senior) Product Engineer (m/f/d)

1KOMMA5° At 1KOMMA5°, we pursue a clear vision: Living on wind and sunlight forever for free. To make this a reality, we are building the energy system of the future with Heartbeat AI. Want to be part of it?We bring together regional craftsmanship and scalable software: We don't think of solar, batteries, heat pumps, and e-mobility as isolated components, but control them as an intelligent, integrated overall system in our virtual power plant. Directly connected to the electricity market – in real time, fully automated. This way, energy is used when it is available from renewables and particularly cost-effective. By 2030, our goal is to transition 1.5 million households to renewable energies. Over 3,000 people are working towards this every day, at more than 80 locations worldwide, from Finland to Australia. Want to take responsibility and build solutions that truly matter? Apply now and help us shape the energy world of tomorrow. Learn more about our Product & Tech team! Your mission You will help shape the virtual assembly line team - our intelligence workflow engine building solutions in Growth and Operations to scale our products globally with maximum efficiency and quality. This is a builder role at the intersection of engineering and product: you co-define what gets built, ship it fast, and use AI as a force multiplier at every step. As a (Senior) Product Engineer at 1KOMMA5°, you will take end-to-end ownership of features and workflows, making key decisions on architecture, integration layer, and solution design. You'll collaborate closely with product managers, designers, and engineers across teams to ship things that genuinely move the needle for our customers - and you won't be shy about challenging assumptions or proposing a better direction. Our Stack: TypeScript, React / Next.js (frontend) and Node.js / NestJS (backend)AI-assisted development with Cursor and Claude CodeGCP / Vercel, GitHub Actions (CI/CD)Linear, Notion, Figma, Miro Key responsibilities include but are not limited to: Own feature development end-to-end, from problem framing to production deployment and long-term maintenanceBuild and integrate AI-powered product experiences using LLMs, agents, and tool-use patternsDefine feature scope together with PMs - engage with the "why", not just the "what"Contribute to architectural decisions, API design, and AI integration patterns across the teamsKeep feedback loops short: prototype, ship to real users, observe, adjustPush back when something doesn't make sense and propose better approaches Your profile Strong fullstack proficiency in TypeScript, React / Next.js, and Node.js / NestJSReal, demonstrable experience building with LLMs, APIs, or MCPs - production use preferredA product and customer mindset: you think about user problems, not just implementation eleganceProven ability to own features end-to-end, from rough problem statement to shipped, maintained productExperience working closely with PMs and designers in a cross-functional teamExcellent written and spoken English; German is a plusResidency in Germany Bonus points for: Experience with agentic systems, tool-use patterns, or RAG pipelinesFamiliarity with the energy market, construction, sales, or climate tech contextPrior experience in a startup or scale-up Benefits You are part of an international, dynamic, and highly motivated team of people who have proven to make things happenWith your work, you accelerate the "energy transition" and hence have a direct impact on our climateWork with and learn from other super-smart colleaguesYou will enjoy direct contact with core decision-makersYou will enjoy the best chances of entering full-time in one of Europe’s most thriving scaleupsYou work remotely (Germany-wide), with offices in Hamburg, Berlin or MunichCreate a healthy balance alongside your work and enjoy all the benefits of the EGYM WellpassBenefits and discounts are yours with FuturebensWhether city bike or e-bike - be flexible with our job bike leasing and do something good for the environment at the same time About Us "At 1KOMMA5°, our vision is to accelerate CO2 neutral life for all! We created an easy one-stop-shop to buy and install solar, charging stations and heat pumps, with the purpose of liberating all European homes from the shackles of fossil fuels. With Heartbeat, we make clean energy smarter. Connecting our customers into one powerful clean energy operating system to enable flexible tariffs and to ultimately follow the rhythm of wind and sun!" - Philipp Schröder (CEO 1KOMMA5°)