AI Senior Software Engineer

About Wallround  Wallround is headquartered in Berlin, with additional locations in Hamburg, Frankfurt am Main, Munich, Friedrichshafen and NRW.  Our mission: we turn energy-efficient retrofits for multi-family residential buildings into predictable, lucrative investment opportunities. When it comes to modernisations, the real estate market is often a black box of rough estimates and fragmented processes. We are changing that. Through our integrated platform and streamlined workflow, we transform 'brown assets' into future-proof, high-yield properties. About the Role Department: Prod & Tech Functional Home: AI Reports to: CPO Location: Germany / Europe Seniority: Senior We are looking for AI Senior Software Engineers to design and build the technical foundation behind our AI-powered products. You will be part of the AI Functional Home while working primarily within cross-functional product squads. You will collaborate closely with the AI Lead Product Manager, Product Design, Full-Stack and Backend Engineers, and Automation Engineers. This role is ideal for an engineer who enjoys moving between AI experimentation and production software engineering - taking an idea from prototype to reliable, scalable customer-facing functionality. Key Responsibilities AI Engineering - Design and implement production-grade AI features and services. - Work with LLMs, multimodal models, embeddings, RAG, agents, and AI APIs. - Design AI workflows that are reliable, observable, and maintainable. - Evaluate models and AI approaches against product requirements. - Develop strategies for accuracy, hallucination reduction, latency, and cost optimization. Product Development - Work directly with the AI Product Manager to turn product requirements into technical solutions. - Rapidly prototype new AI capabilities and validate technical feasibility. - Take successful prototypes into production. - Contribute to technical product decisions and architecture. AI Infrastructure & Quality - Build evaluation frameworks and testing approaches for AI systems. - Implement monitoring and observability for AI applications. - Establish appropriate guardrails and fallback mechanisms. - Monitor model performance, latency, availability, and cost. - Help establish reusable AI infrastructure and engineering patterns. Cross-Functional Squad Execution - Act as a senior technical contributor within the AI Product Squad. - Collaborate with Product, Design, Backend, Full-Stack, and Automation specialists. - Break complex AI initiatives into executable technical work. - Mentor other engineers and raise engineering standards across the AI Team. - Participate in architectural and technical decision-making. What We are Looking For - 6+ years of professional software engineering experience. - Significant experience building production software using TypeScript and/or Java Python. - Hands-on experience building applications with LLMs or other modern AI technologies. - Strong understanding of APIs, distributed systems, databases, and cloud infrastructure(AWS, GCP, or Azure). - Experience taking AI prototypes into production. - Strong software engineering fundamentals: testing, version control, code review, observability, and maintainability. - Ability to operate autonomously in a fast-moving product environment. - Experience with RAG architectures and vector databases. - Experience building AI agents and tool-calling systems. - Experience with model evaluation and AI observability. - Experience with LangChain, LlamaIndex, or equivalent frameworks. - Experience with multimodal AI. - Experience building B2B SaaS products. Success in the First 6–12 Months - Deliver production-grade AI capabilities. - Establish reliable AI engineering and evaluation patterns. - Improve the quality, reliability, and cost efficiency of AI features. - Build reusable AI components that accelerate future squads. - Mentor engineers and contribute to the technical direction of the AI Team. What You’ll Own AI Architecture → AI Engineering → Production AI Systems → Evaluation → Reliability → Technical Excellence Why Join Wallround? - Impact: Shape the future of energy-efficient retrofits and make a real contribution to climate action. - Growth: Be part of a fast-growing startup with huge market potential. - Team & Culture: Work alongside a highly motivated, experienced team in Berlin (Kreuzberg). Enjoy a vibrant startup culture, regular team events, and a modern workplace. - Innovation: Flat hierarchies and fast decision-making—your ideas matter from day one. - Flexibility & Development: Competitive salary, flexible working hours, and tailored personal growth opportunities. - Perks & Benefits: €150 monthly benefit budget—use it for public transit tickets, meal allowances, or lifestyle perks (e.g., Urban Sports Club membership or vendor vouchers).