Senior Backend Engineer

We’re on the lookout for an ambitious Senior Backend Engineer to join our Core data team at our office in Berlin. Join us in building the largest AI enabled fintech for healthcare! Core Data is responsible for providing data to product feature development and agent building teams across Nelly - effectively an MCP for the rest of the company. We own the ingestion pipelines, the canonical data model, and the tooling that lets product and AI teams build on top of clean, reliable data. 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 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. No egos, no drama. Just kind, curious, hardworking humans building something meaningful together. If that sounds like your kind of place, welcome to Nelly. JOINING US, YOU WILL - Design and build ingestion pipelines that pull data from third-party PMS systems into Nelly's core data model. - Own backend services in TypeScript/Node.js on AWS - event-driven, idempotent, observable. - Evolve the canonical data model that every product team at Nelly builds on. - Build the MCP servers and AI tooling that expose Core Data to internal agents and LLM-powered workflows - a chance to shape how AI ships at Nelly. - Partner with product teams to triage and resolve ingestion issues by impact. WHAT YOU'LL BRING - 8+ years backend-leaning experience, strong TypeScript/Node.js. - Deep experience with data pipelines, ETL/ELT, and third-party integrations (queues, retries, idempotency, schema evolution). - Strong data and API modeling - you've designed schemas that survived three product pivots. - AWS in production. - Bonus: healthcare/fintech data, event sourcing, MCP/LLM tooling experience. 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.