Senior Machine Learning Engineer - Applied AI & LLMs (x/f/m)

Your Impact We are looking for a Senior Machine Learning Engineer to join the ML Engineering team in Patient Solutions . Your mission will be to improve how people access quality care and manage their health over time by building and leading AI and ML systems that create real, measurable impact. You will work in a feature team developing intelligent patient-facing solutions, from smart practitioner discovery to long-term care management, playing a key technical role in shaping how we scale our AI capabilities across Europe. Working in the tech team at Doctolib means building innovative products and features to improve the daily lives of care teams and patients. What you'll do Your responsibilities include but are not limited to: Design and implement ML and AI solutions aligned with patient product goals, covering search, retrieval, and personalized care pathways Build and maintain large-scale retrieval pipelines, including hybrid search, embedding systems, vector databases, and multi-stage re-ranking architectures Develop, fine-tune, and evaluate LLM and VLM models using techniques such as knowledge distillation, Mixture-of-Experts (MoE) architectures, and prompt engineering Build and orchestrate agentic AI systems, integrating external data and capabilities through tools and MCP-based integrations Define metrics aligned with product goals, run controlled end-to-end experiments using W&B, MLFlow, or Braintrust, and communicate findings to guide product and technical decisions Deploy solutions to production in collaboration with our ML platform team, ensuring reliability, observability, and performance at scale, and act as a technical reference to elevate the team's standards and practices Who you are Before you read on: if you don't have the exact profile described below, but you feel this job description matches your skill set, we still encourage you to apply. You'll be a great fit if you: You have 7+ years of experience in Machine Learning, Deep Learning, or AI Engineering, with a strong track record of taking models from prototype to production at scale You have strong experience in Information Retrieval and modern retrieval stacks: hybrid search (sparse + dense), large-scale embeddings and vector databases, multi-stage retrieval and re-ranking pipelines, RAG architectures, and tool/MCP-based integrations You are proficient in LLM and VLM application development: fine-tuning, MoE architectures (via LiteLLM or Model Garden), knowledge distillation, prompt engineering, and systematic benchmarking of LLM/VLM systems You have hands-on experience building and orchestrating agentic AI systems (e.g., using ADK) You demonstrate strong scientific rigor: designing metrics aligned with product goals, running controlled experiments, and communicating results clearly to both product and engineering stakeholders You have experience operating large-scale applications in production (monitoring, reliability, performance, observability), bring strong analytical skills, and approach your work with a user-first mindset. You are fluent in English It would be fantastic if you: Have experience in B2C marketplace environments Have experience in other ML methodologies: pattern mining, recommendation systems, experimentation, or causal inference Life at Doctolib Tech Our solutions are built on a single fully cloud-native platform that supports web and mobile app interfaces, multiple languages, and is adapted to country and healthcare specialty requirements. Our stack is composed of Rails, TypeScript, Java, Python, Kotlin, Swift, and React Native. We leverage AI ethically across our products to empower patients and health professionals. Discover our AI vision here . Want to learn more about our tech culture and environment? Visit the Doctolib Tech site . What we offer Free comprehensive health insurance (basic package) for you and your children 25 days of paid vacation per year, plus up to 14 days of RTT Free mental health and coaching services thro…