Staff AI Engineer
Nelly
Software Engineering, Data Science
Berlin, Germany
Posted on Dec 1, 2025
We celebrate diversity and encourage individuals of all genders (m/f/d) to apply.
We’re on the lookout for an ambitious AI-Engineer to join our Engineering team at our office in Berlin. Join us in building the largest AI enabled fintech for healthcare!
As part of our freshly launched AI division at Nelly, where you'll be one of the pioneers shaping our future in AI. In a small, agile team, you'll work on developing cutting-edge AI systems and robust data pipelines—from rapid prototypes to scalable production solutions. This role is ideal for someone who combines deep ML theory with practical cloud and data engineering know-how, and who can drive innovative GenAI initiatives while keeping a pragmatic product focus.
About Nelly
At Nelly, we’re revolutionizing medical practice management with AI-driven automation and seamless digital workflows. Our innovative solutions - from best-in-class patient journeys, AI enabled patient relationship management and billing to state of the art payment solutions - eliminate painful workflows and improve financial outcomes making healthcare administration smarter, faster, and 100% digital.
To fuel our mission, we just raised €50M in our Series B, backed by top-tier investors like Cathay, Notion, Lakestar, GFC, b2venture, and Motive Partners. With this momentum, we’re on a mission to build Europe’s largest fintech in healthcare - bringing best-in-class financial and operational solutions to over 1 million medical practices serving millions of patients daily.
Join us now if you’re driven by impact, excited by fast-paced innovation, and ready to shape the future of healthcare!
Joining us, you will
- embrace a fast-paced, agile environment where outcome and quick progress is achieved through experimentation and rapid iteration.
- architect and lead the development of backend-first agentic services combining LLM services with tool use/retrieval, ReAct and Knowledge Graphs - defining technical strategy, standards, and best practices across the AI division.
- design and evolve our retrieval & knowledge infrastructure (embeddings, vector stores, metadata schemas, glossary, memories) ensuring accuracy, performance, and scalability across diverse use cases.
- define and champion production excellence: establishing standards for tracing, observability, reliability patterns, prompt/version control, experimentation frameworks, and deployment strategies.
- mentor engineers, conduct technical reviews, and elevate the team's capabilities through knowledge sharing and best practices.
- drive technical discovery, evaluate emerging AI technologies, and make strategic build vs. buy decisions.
- partner closely with product and business stakeholders to translate complex technical considerations into product strategy and roadmap decisions.
What you'll bring
- technical leadership mindset with high agency and proactive drive—obsessed with building world-class systems and enabling teams to ship exceptional user experiences.
- 8+ years building and operating backend systems in production (strong Python skills required - ideal as well: TypeScript for integration work), with 3+ years shipping LLM/GenAI features to users (RAG, tool use, planning, agent frameworks e.g MCP, multi-agent systems).
- strong ML fundamentals with hands-on experience in model evaluation, self-evolving agents (e.g Memory).
- deep expertise in distributed systems design: API architecture, data modeling, high-throughput async systems, event-driven architectures, caching strategies, and performance optimization.
- advanced retrieval engineering experience: embeddings, sophisticated chunking strategies, hybrid search algorithms, schema/metadata design, knowledge graphs, comprehensive eval frameworks, and production monitoring.
- proven track record of technical leadership: driving architecture decisions, mentoring engineers, and establishing engineering best practices.
- experience with cloud native development at scale, ideally AWS, but GCP is a strong plus, too.
- excellent communication skills in English with ability to articulate complex technical concepts to diverse audiences.
- Experience with modern data workflow orchestration frameworks such as Dagster, Airflow, or Prefect, with emphasis on building robust, dependency-aware pipelines at scale.
- Track record of technical writing, open-source contributions, or speaking at industry events.
- Fluent German is a big plus, to improve the interaction between you and our user base.
Bonus skills:
What we offer
- Competitive salary
- Work in a great team of talented and highly motivated people
- Dynamic environment, steep learning curve, and extensive development opportunities
- Part of an exciting FinTech startup in the German healthcare market
- Responsibility, independent work, and high flexibility
- Generous budget for learning and development
- First-class work equipment and flexible working hours
- Deutschlandticket or Swapfiets rental bike
- Urban Sports Club membership
We are looking forward to receiving your application and welcoming you to the team.