About the Position

Principal Machine Learning Engineer – Applied AI & LLMs (x/f/m)

Unlimited Contract

Engineering

Berlin, Germany

About Doctolib

At Doctolib, we’re reinventing the daily lives of health professionals and empowering people to live healthier across Europe.

More than 3,000 Doctolibers across France, Germany, Italy, the UK, and the Netherlands are building a new generation of AI-powered technologies and services, trusted by 580,000 health professionals and over 100 million patients every day.

AI is at the heart of how we build and how we work. At Doctolib, AI fluency is a core skill for every team member: we foster a culture leveraging AI to drive efficiency, quality, and impact at scale.

Responsibilities

As a Principal Machine Learning Engineer, you will:

Own cross-team ML architecture decisions, from model selection to production deployment patterns and strategic build vs. buy decisions.
Define and drive adoption of rigorous evaluation frameworks across all AI teams, setting the standard for how Doctolib measures model and agentic performance.
Establish shared production infrastructure patterns for AI: model and prompt versioning, guardrails, uncertainty quantification, cost optimization, and observability.
Lead the technical design of agentic solutions and define how product teams across Doctolib build on top of AI capabilities.
Elevate technical standards across the DS & AI org by influencing Staff and Senior ML Engineers through architecture reviews, technical guidance, and practice propagation.
Partner with Product, Legal, and Compliance teams to ensure safe rollout and meet EU regulatory expectations (GDPR, MDR, EU AI Act).

Requirements

10+ years in ML/AI with 3+ years at Staff+ or Principal level leading complex, multi-team technical initiatives.
Deep expertise in at least two of: clinical NLP, LLM fine-tuning and evaluation, automatic speech recognition, RAG systems, or reinforcement learning.
Expert in Python, PyTorch/Transformers for training, and vLLM for inference with a track record deploying ML systems in production (AWS/GCP).
PhD in Computer Science, AI, Statistics, or related field (or equivalent research experience).
Exceptional communication skills and the ability to align diverse stakeholders and explain complex technical decisions.

Nice to Have

Publications in top-tier ML/AI conferences (NeurIPS, ICLR, ACL) or medical informatics venues.
Experience with EU healthcare regulations (GDPR, MDR, AI Act).
Prior work with clinical data or healthcare applications.

We Offer

A Deutschlandticket (Germany-wide public transport pass) fully paid for by Doctolib.
28 vacation days + 1 additional day for each full calendar year of employment (up to a maximum of 30 days).
Work from abroad for up to 10 days per year thanks to our flexibility days policy.
Company health insurance with great supplementary benefits through our partner Allianz.
Company pension scheme (bAV) through Allianz with an employer subsidy of 40% (15% within the probationary period).
The Doctolib Parent Care program, which includes one month additional parental leave and much more.
Enrollment in Doctolib's long-term employee value sharing plan called DoctoGrowth.
Free mental health and coaching services through our partner Moka.care.
Subsidized sports membership through our partner Urban Sports Club.
A flexible workplace policy offering both hybrid and office-based mode.
Alongside healthy snacks and our regular breakfast buffet, we provide a subsidized meal benefit.
For caregivers and workers with disabilities, a package including an adaptation of the remote policy, extra days off for medical reasons, and psychological support.
Relocation support in case of international mobility.
Access to the best AI tools for coding, development, and dedicated training.

The Interview Process

HR Screen
Hiring Manager Interview
Technical Interview
Technical Case Study
Behavioral Interview
At least one reference check

We want your experience to be clear, respectful, and transparent. Learn more on our candidate experience page.

Job Details

Permanent position
Full-time
Berlin
Hybrid work mode (up to 2 remote days per week)
Start date: as soon as possible

We Welcome Everyone

At Doctolib, we believe in improving access to healthcare for everyone - regardless of where you come from or what you look like. We evaluate candidates based solely on qualifications and motivation, without any form of discrimination. We respect and celebrate diversity!

The more diverse ideas are heard, the more our product will truly improve healthcare for all. You are welcome to apply regardless of gender, religion, age, sexual orientation, ethnicity, disability, or place of origin.

To ensure equal opportunities, we invite you to exclude personal information (e.g., pictures, age) from your applications. If you have a disability, let us know if there's any way we can make the interview process smoother for you! Join us in building the healthcare we all dream of.

Your Data Privacy

All information transmitted via this form is processed by Doctolib for application management. For more on how we process your data, click here. For inquiries or to exercise your rights, contact us at hr.dataprivacy(at)doctolib.com.

Principal Machine Learning Engineer – Applied AI & LLMs (x/f/m)

Job description