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! 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 Code GCP / 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 maintenance Build and integrate AI-powered product experiences using LLMs, agents, and tool-use patterns Define 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 teams Keep feedback loops short: prototype, ship to real users, observe, adjust Push back when something doesn't make sense and propose better approaches Strong fullstack proficiency in TypeScript, React / Next.js, and Node.js / NestJS Real, demonstrable experience building with LLMs, APIs, or MCPs - production use preferred A product and customer mindset: you think about user problems, not just implementation elegance Proven ability to own features end-to-end, from rough problem statement to shipped, maintained product Experience working closely with PMs and designers in a cross-functional team Excellent written and spoken English; German is a plus Residency in Germany Bonus points for: Experience with agentic systems, tool-use patterns, or RAG pipelines Familiarity with the energy market, construction, sales, or climate tech context Prior experience in a startup or scale-up