Senior Software Engineer – AI Systems (m/w/d)

Place of work: Essen (head office) or Berlin possible

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Here's what you can look forward to

• Design, build, and operate production- grade AI Agents using Java/Kotlin — from first prototype to reliable live service
• Integrate Large Language Models and AI capabilities into backend services and APIs
• Own AI features end- to- end: architecture, implementation, deployment, monitoring, and continuous improvement
• Build scalable agent services on Kubernetes with a strong focus on reliability, performance, and cost awareness
• Collaborate closely with product, platform, and domain teams to turn real business problems into AI- powered solutions
• Establish engineering best practices for AI systems: testing strategies, observability, fallback mechanisms, and safe deployment
• Contribute to architectural decisions around agent platforms, shared components, and internal AI tooling

What we require of you

• Strong professional experience as a Backend / Software Engineer, ideally with Java or Kotlin in production environments
• Solid understanding of modern backend architectures (REST, microservices, event- driven systems)
• Hands-on experience running services on Kubernetes, including deployment, scaling, and operational troubleshooting
• A systems mindset: you think beyond individual endpoints and consider reliability, latency, and failure modes
• Experience building APIs and services that are observable, testable, and maintainable
• Familiarity with CI/CD pipelines, containerization, and cloud- native development
• Interest in applied AI: integrating LLMs or similar models into real products and willingness to learn and iterate quickly in a fast- moving AI landscape
• You value clean interfaces, automation, and pragmatic engineering over hype

Nice to have:

• Experience with prompt engineering, embeddings, or agent frameworks
• Exposure to AI evaluation techniques or production monitoring of AI systems
• Frontend experience (e.g., Angular)

What we offer you

• Do the right thing with purpose and a future: our services save CO2 and protect the environment - we are working for a sustainable world of tomorrow
• Enjoy many benefits: Look forward to an attractive salary, 30 days' vacation per year and flexible working hours, including the opportunity to work up to 50% of the week on a mobile basis
• Secure good prospects for yourself: We are an internationally successful company with agile working methods and an open corporate culture. Our future course offers you long-term and excellent career options.
• Stay curious and develop yourself further: standing still is not an option for us, which is why we support you in every aspect of your development - a variety of learning opportunities await you
• Experience a working environment full of trust: We all pull together
• Have fun in a motivated team: Whether it's a barbecue event, international soccer cup or ice cream for everyone in summer - we always come up with something new, so stay tuned!

What do we do at ista?

At ista, we support property owners and managers in making their buildings future-proof and climate-neutral. This includes measuring, billing, and making energy consumption transparent. In this way, we help to save energy and CO2. We work on this with over 6,300 employees in 20 countries. We offer you the security of a successful company and the flexibility of an agile way of working. Join us in shaping the future.

At ista, everyone is welcome regardless of age, gender, origin, sexual orientation, religion, or disability. We are proud to be part of a diverse team. We foster a collegial environment and support each other. We place a high value on work-life balance. The advancement of our employees is also very important to us, which is why we offer everyone the opportunity for further training and development.