Senior AI Engineer

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 We are a Tech Company and we believe healthcare should feel a lot less like paperwork… and a lot more like people. So we’re building the technology that lets medical practices run smoothly, simply, and without all the admin chaos that slows everyone down. Our platform turns messy processes into smart, automated workflows, from patient journeys to billing to next-generation payments. Powered by AI, built for real humans, and designed to give medical teams the time and headspace they desperately need. Why? Because Europe is facing a massive shortage of medical assistants. And if we don’t rethink how practices operate, the system won’t be able to keep up. We’re here to fix that, not with band-aids, but with real transformation. We’re backed by €50M in Series B funding from world-class investors and are scaling fast to build Europe’s leading healthcare fintech. Our vision: empower over a million medical practices and make life better for millions of patients. But here's the part we’re proudest of: we only work with nice people . It’s our number-one rule. No egos, no drama, no jerks. Just kind, curious, hardworking humans building something meaningful together. If that sounds like your kind of place — welcome to Nelly. 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. Bonus skills: 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. Our tech stack : TypeScript, Node.js, React, Python, FastAPI, Kubernetes, MongoDB, Azure, Kafka, NATS. What we offer BVG ticket or a Swapfiets membership to cruise through the city Urban Sports membership to sweat, stretch, or sauna your way through the week Top of the line working equipment Flexible hours and a hybrid setup in the heart of Berlin Enjoy up to 4 weeks of workation wherever inspiration hits A cozy, dog-friendly office where good vibes are basically mandatory A fridge full of cold drinks and snacks waiting to be claimed We celebrate diversity and welcome individuals of all genders (m/f/d) to apply — and because we know confidence gaps and impostor syndrome can get in the way, please don’t hesitate even if you don’t meet every single criterion; if you’re exceptional, tell us why, and we’d genuinely love to hear from you.