Senior AI Engineer
Nelly
Software Engineering, Data Science
Berlin, Germany
Posted on Dec 2, 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.
- Design and ship backend-first agentic services combining LLM services —taking full responsibility for system design, APIs, and data integrity.
- Build retrieval & knowledge layers (embeddings, vector stores, metadata schemas, glossary, memories) that make suggestions accurate across different input scenarios.
- Own production quality: tracing, retries, fallbacks, prompt/version control, AB tests, feature flags, rollbacks.
- Support user interviews, contribute to product planning, and collaborate with cross-functional teams to drive impactful projects.
What you will bring
- Builder and owner mindset,with high agency and proactive drive to move fast - obsessed with shipping the best user experience and winning on product.
- 6+ years building and operating backend systems in production (strong Python skills required - ideal as well: TypeScript for integration work towards customer-facing app. ), with 1-2 years shipping LLM/GenAI features to users (RAG, tool use, planning, or agent frameworks e.g MCP).
- Proven experience in systems design: API design, data modeling, high load async worker queues, eventing, caching
- Retrieval engineering experience: embeddings, chunking, similarity search, hybrid search algorithms, schema/metadata design, knowledge graphs, eval dataset design, and offline/online evals.
- Experience with cloud native development, ideally AWS, but GCP is a strong plus too.
- Great communication skills in English.
- Applied ML fundamentals alongside theoretical experience
- Experience with modern data workflow orchestration frameworks such as Dagster, Airflow, or Prefect, with emphasis on dependency-aware pipelines
- 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.