Senior Reinforcement Learning Engineer

Doctolib

What you’ll do We are looking for a Principal Machine Learning Engineer to join the DS & AI organization at Doctolib. This is a transversal force multiplier role operating across all AI teams: Clinical, Productivity, Phone Assistant and ASR. Rather than working within a single feature team, you will own the cross-cutting technical challenges: defining how Doctolib's product and AI teams build agentic solutions, standardizing ML evaluation frameworks, and spreading strong engineering practices across the org. You will unblock teams, shape architecture decisions, and take on the deep technical work that requires senior ML judgment at scale, directly impacting the daily lives of 400,000 healthcare professionals and the health of 80 million patients. Building at Doctolib means delivering innovative products that measurably improve outcomes for care teams and patients alike.   Technical Strategy & Architecture * 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)   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 have 10+ years in ML/AI with 3+ years at Staff+ or Principal level leading complex, multi-team technical initiatives * You have deep expertise in at least two of: clinical NLP, LLM fine-tuning and evaluation, automatic speech recognition, RAG systems, or reinforcement learning * You are expert in Python, PyTorch/Transformers for training, and vLLM for inference with a track record deploying ML systems in production (AWS/GCP) * You have a PhD in Computer Science, AI, Statistics, or related field (or equivalent research experience) * You have exceptional communication skills and are able to align diverse stakeholders and explain complex technical decisions Now it would be fantastic if you 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   Life at Doctolib Tech * Our solutions are built on a single fully cloud-native platform supporting web and mobile interfaces across multiple languages and healthcare specialties. * Our stack includes Rails, TypeScript, Java, Python, Kotlin, Swift, and React Native. * We leverage AI ethically to empower patients and 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 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 our partner Moka.care * Work from abroad for up to 10 days per year thanks to our flexibility days policy * Lunch vouchers with Swile card (€8.50 value, €4.50 covered by Doctolib) * Work Council subsidy for sports club memberships or creative classes * 50% reimbursement of your public transport subscription * Parent Care Program: one additional month of leave on top of legal parental leave * For caregivers and workers with disabilities: remote policy adaptation, extra medical leave, and psychological support * Relocation support for international mobility * Access to premium AI tools for 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 * Paris, France * 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.

Doctolib

WHAT YOU’LL DO We are looking for a Senior Staff Machine Learning Engineer to join the Clinical team in the AI and Machine Learning Department. You'll lead the technical direction of AI systems that enhance clinical decision-making and patient care. You'll tackle the hardest problems in healthcare AI, from building voice-powered consultation assistants to establishing LLM evaluation frameworks that ensure clinical safety and efficacy. This role combines deep R&D with strategic technical leadership, shaping how Doctolib deploys AI in regulated healthcare environments. Your responsibilities include but are not limited to: Technical Strategy & Architecture * Own the long-term technical roadmap for clinical ML systems, from model architecture selection to production deployment patterns * Drive strategic build vs. buy decisions, balancing custom development with foundation model APIs * Define standards for safe rollout in healthcare contexts: shadow testing, staged deployment, and human-in-the-loop workflows End-to-End ML Delivery * Lead design and implementation of LLM-powered clinical agents (consultation summarization, clinical coding, evidence-grounded recommendations) * Establish rigorous evaluation frameworks using real-world clinical datasets, ensuring outputs meet clinical accuracy and safety standards * Build production infrastructure: model and prompt versioning, guardrails, uncertainty quantification, cost optimization, and observability * Define a bold strategy for online and offline performance objectives to reach new levels of healthcare professionals satisfaction Leadership & Impact * Mentor Staff or Senior ML Engineers and Applied Scientists, elevating technical standards across the organization * Lead cross-functional initiatives spanning Product, Medical Affairs, Legal, and Compliance teams * Translate clinical needs into research questions and production systems that measurably improve patient outcomes * Partner with our medical, legal, and compliance teams to meet EU regulatory expectations (e.g., GDPR, MDR, upcoming EU AI Act) and market standards.   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 have 10+ years in ML/AI with 3+ years at Staff+ or Principal level leading complex, multi-team technical initiatives * You have a PhD in Computer Science, AI, Statistics, or related field (or equivalent research experience) * You have deep expertise in at least two of: clinical NLP, LLM fine-tuning and evaluation, automatic speech recognition, RAG systems, or reinforcement learning * You are expert in Python, PyTorch/Transformers for training, vLLM/similar for inference with a track record deploying ML systems in production (AWS/GCP) * You have exceptional communication skills and are able to align diverse stakeholders and explain complex technical decisions Now it would be fantastic if you 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 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 our partner Moka.care * Work from abroad for up to 10 days per year thanks to our flexibility days policy * Lunch vouchers (Swile card) worth €8.50 per working day, with €4.50 covered by Doctolib * A subsidy from the work council to refund part of the membership to a sport club or a creative class * 50% reimbursement of your public transport subscription * ParentCare Program: Enjoy full salary coverage (100%) during your first month of birth leave, and 75% during the second, covered by Doctolib * Enrollment in Doctolib's long-term employee value sharing plan called DoctoGrowth * 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 * Behavioral Interview * Technical Questions  * Technical Case Study * At least one reference check   JOB DETAILS * Permanent position * Full-time * Hybrid work mode (3 days/week in the office) * Paris, France * Start date: as soon as possible   If you would like to find out more about tech life at Doctolib, feel free to read our latest Medium blog articles! At Doctolib, we are committed to improving access to healthcare for everyone. This translates into our recruitment process. We evaluate candidates based solely on qualifications and motivation, without any form of discrimination. The more diverse ideas are heard, the more our product will truly improve healthcare for all. You are welcome to apply to Doctolib, regardless of your gender, religion, age, sexual orientation, ethnicity, disability. To ensure equal opportunities, we invite you to exclude personal information (e.g. pictures, age) from your applications. If you require any accommodation, please let us know for support during the hiring process. Join us in building the healthcare we all dream of! All information provided is processed by Doctolib for application management. For data processing details, click here. Please contact hr.dataprivacy(at)doctolib.com for inquiries or to exercise your rights.   * *

tem

📈 Who We Are: We are rebuilding the energy transaction, making it transparent and fair. Our goal is to put power back where it belongs, in the hands of customers and to take on one of the most critical problems of our century, access to low cost electricity. tem exists to fix a broken global energy market that’s long favoured legacy operators, intermediaries, and opaque pricing. Today’s electricity system was not designed for rapid decarbonisation, AI-driven efficiency or fair access for the actual users - businesses and generators. We’ve built the first AI native transaction infrastructure to reinvent how electricity is bought, sold and priced. Our technology is designed to cut out the inefficient fees, automate complex market flows, and bring transparency and fairness to energy transactions at scale. In late 2025, after extraordinary growth, we closed a $75 million Series B - led by Lightspeed Venture Partners with participation from Albion, Atomico, Allianz, Hitachi Ventures, Hitachi Ventures, Schroders Capital and others - positioning us for global expansion, deeper product innovation and category leadership. We’re scaling internationally and building toward a future where AI-driven infrastructure is foundational to electricity markets worldwide. Since launch, our modern utility product, known as RED, has already facilitated thousands of business customers and billions in energy transaction value, proving that modern software and AI can transform an industry built on legacy systems. At tem, we’re not just building another energy company, we’re rearchitecting market infrastructure so that transparency, efficiency and sustainability become the default, not the exception. 🏅 The Role: Rosso is tem's core IP, the transaction infrastructure that prices electricity for thousands of businesses, balances portfolios in real time, and sits on the critical path for every deal tem closes. Machine learning is at the heart of Rosso, combining forecasting, optimisation and classical ML to process billions of data points and drive thousands of automated decisions a day. Every inference shapes the prices our customers see, so you can immediately see the impact of your work. We have proved the concept with MVPs and POCs to grow to 2% of the UK market. Now we want to take it to the next level and build towards a state of the art solution, to fuel our expansion in the UK and take Rosso international. We're looking for a Senior Staff Machine Learning Engineer to lead pricing ML within Rosso, building a platform that proactively drives growth by targeting the right customers to sign at the right time. Your primary focus will be the pricing engine, which sets the fees added to every quote tem serves, carefully balancing growth and margin. You will also contribute to the systems which manage both short and long-term imbalance decisions to determine how tem deals with it’s exposure across its portfolio. This is a hands-on, senior individual contributor role with significant technical leadership and organisation-wide influence. You will work closely with other MLEs, software engineers and MLOps to bring models to production, and carry real ownership of the technical direction and accountable for its performance. The right person is energised by the greenfield environment: comfortable taking on ambiguity and able to make progress before the path is fully defined. They have built pricing systems that worked and have learned from the times it hasn't. They'll bring that hard-won judgment to a system where the foundations are still being laid, and where early decisions compound. Success will be turning our current reactive system into a pricing engine which proactively drives growth by targeting the right customers to sign at the right time. 🚀 Responsibilities: * Own the technical direction for pricing ML: Define what to build and how within the pricing engine, setting the strategy and roadmap for pricing machine learning as a core piece of tem's IP. * Build ML systems for price optimisation: Design and implement models that dynamically set prices, balancing the trade-off between signing probability, portfolio balance and margin maximisation. * Solve imbalance problems: Develop probabilistic models to optimise risk management and short-term balancing decisions in a highly dynamic environment. * Bridge modelling and production: Own the modelling and data layer while working closely with software engineers and MLOps to ensure models are architected for production, contributing to system design decisions that affect performance and reliability. * Communicate pricing decisions clearly: Articulate model behaviour, assumptions, and trade-offs to other technical stakeholders so that pricing decisions are understood across the teams that depend on them. 🎯 Requirements: Must-haves: * Deep experience building ML systems for pricing, revenue optimisation, or decision-making under uncertainty, with a track record of models that went from concept to production and delivered measurable commercial impact. * Strong foundation in stochastic optimisation and probabilistic modelling, with the judgement to formulate ambiguous business problems as the right mathematical approach rather than reaching for familiar tools. * Proven first-principles reasoning: you choose between stochastic programming, classical ML, reinforcement learning, or a simple heuristic based on the problem, not the technique you know best. * The engineering craft to match your modelling depth: production-grade Python, a high bar for code quality and system design, and the ability to work alongside software engineers as a technical peer across the full ML lifecycle. * Senior technical leadership in ML: a track record of setting direction for a significant technical area, influencing cross-functional teams, and translating complex model decisions into clear terms for commercial, product, and engineering stakeholders so they are understood and acted on. Bonus points: * Experience with reinforcement learning or causal inference in applied, commercial settings. * Familiarity with energy markets, power trading, or portfolio management. * PhD or equivalent research depth in a quantitative discipline (statistics, applied mathematics, physics, operations research, or similar). * Ability to reason about the trade-offs between optimisation solvers (Gurobi etc) and gradient-based ML methods (PyTorch etc), and the judgement to know when to reach for each. * Experience working with high data throughput systems in production. 🗣️ Interview Process: Our processes normally take around 2-3 weeks from first call to offer - please let us know about any adjustments to timelines that may be required. 1. First call with our Talent Team (30 Mins). This is to understand your experience, motivations, and discuss the role in more detail. 2. Behaviour Interview with our Rosso GM, hiring manage for this role (45 Mins). This is your chance to really understand the role, the expectations, and ensure alignment on ways of working. 3. Technical Interview with the Team (90 Mins). You’ll meet with potential peers in this session and will discuss technical topics and experiences. 4. Culture-Add Interview with Stakeholders (45 Mins). The final session will be with two cross-functional stakeholders, and will explore how your values align with ours, and is designed to be a genuine two-way conversation, your chance to understand what it’s really like to work at tem. We welcome applications from people of all backgrounds, experiences, and identities, including those that are traditionally underrepresented in the tech and energy sectors. If you’re excited about this role but not sure you meet every requirement, we’d still love to hear from you. Your unique perspective could be exactly what we’re looking for.