Senior Machine Learning Engineer - Applied AI & LLMs (x/f/m)
Doctolib is 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 with real, measurable impact. You will work in a feature team developing intelligent patient-facing solutions, from smart practitioner discovery to long-term care management, shaping how AI capabilities are scaled across Europe. The role is a full-time permanent position at the Paris office in Levallois-Perret with a hybrid setup (3 days per week in the office).
Responsibilities
- ▹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 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 with the ML platform team, ensuring reliability, observability and performance at scale, and act as a technical reference to raise the team's standards
Requirements
- ▹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
- ▹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
- ▹Proficiency 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
- ▹Hands-on experience building and orchestrating agentic AI systems (e.g. using ADK)
- ▹Strong scientific rigor: designing metrics aligned with product goals, running controlled experiments and communicating results clearly to product and engineering stakeholders
- ▹Experience operating large-scale applications in production (monitoring, reliability, performance, observability), strong analytical skills and a user-first mindset
- ▹Fluent English
Nice to have
- ▹Experience in B2C marketplace environments
- ▹Experience in other ML methodologies: pattern mining, recommendation systems, experimentation or causal inference
Soft skills
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 through Moka.care
- ▹Work from abroad for up to 10 days per year
- ▹Lunch vouchers (Swile card) worth €8.50 per working day, with €4.50 covered by Doctolib
- ▹Work council subsidy for sport club or creative class membership
- ▹50% reimbursement of public transport subscription
- ▹Parent Care Program: one additional month of leave on top of legal parental leave
- ▹Enrollment in the DoctoGrowth long-term employee value sharing plan
- ▹Support package for caregivers and workers with disabilities
- ▹Relocation support in case of international mobility
- ▹Access to the best AI tools for coding and dedicated training
About the company
Doctolib builds innovative products and features to improve the daily lives of care teams and patients. Its solutions run on a single fully cloud-native platform supporting web and mobile interfaces, multiple languages and country- and specialty-specific requirements. The stack includes Rails, TypeScript, Java, Python, Kotlin, Swift and React Native, and AI is used ethically across the products.