
PhysicsX · London
ABOUT US PhysicsX is a deep-tech company with roots in numerical physics and Formula One, dedicated to accelerating hardware innovation at the speed of softwar...
PhysicsX is a deep-tech company with roots in numerical physics and Formula One, dedicated to accelerating hardware innovation at
the speed of software.
We are building an AI-driven simulation software stack for engineering and manufacturing across advanced industries. By enabling
high-fidelity, multi-physics simulation through AI inference across the entire engineering lifecycle, PhysicsX unlocks new levels
of optimization and automation in design, manufacturing, and operations — empowering engineers to push the boundaries of
possibility. Our customers include leading innovators in Aerospace & Defense, Materials, Energy, Semiconductors, and Automotive.
NOTE: WE ARE CURRENTLY RECRUITING FOR MULTIPLE POSITIONS, HOWEVER PLEASE ONLY APPLY FOR THE ROLE THAT BEST ALIGNS WITH YOUR
The Principal ML Infrastructure Engineer will extend and operate the infrastructure that powers our research model training,
fine-tuning, and serving pipelines. You will be embedded within our Research function, partnering directly with ML engineers and
research scientists to ensure they can train Large Physics Models efficiently and reliably at scale.
In this role, you will be vertically embedded in Research, working daily with:
You will have end-to-end responsibilities over the research infrastructure, with the autonomy to make architectural decisions and
the responsibility to keep data flowing reliably.
Horizontally, you will be part of an infrastructure engineering group responsible for infrastructure across the company.
etc.) on our large NVIDIA DGX B200 platform.
accumulation, and multi-node synchronization.
hyperparameter sweeps, and model performance.
Carlo Dropout).
fine-tuning capabilities.
converging" into infrastructure hypotheses and solutions, and can bridge technical abstractions with implementations.
FSDP vs. DDP vs. pipeline parallelism
performance optimization
What we offer
Build what actually matters
Help shape an AI-native engineering company at a formative stage, tackling problems that genuinely matter for industry and
society. This is work with real-world impact - and something you can be proud to stand behind.
Learn alongside exceptional people
Work with a high-caliber, collaborative team of engineers, scientists, and operators who care deeply about doing great work, and
about helping each other get better. We come from diverse backgrounds, but we share a commitment to operating at the highest level
and addressing some of the most complex challenges out there. If you’re ambitious, thoughtful, and driven by impact, you’ll feel
at home.
Influence over hierarchy
We operate with a flat structure: good ideas win - wherever they come from. Questioning assumptions and challenging the status quo
isn’t just welcomed, it’s expected.
Sustainable pace, long-term ambition
Building meaningful technology is a marathon, not a sprint. We believe in balancing focused, ambitious work with a life beyond it.
Our hybrid model blends time together in our Shoreditch office with work-from-home days, giving you the flexibility to work
sustainably while staying connected in person.
And it doesn’t stop there …
🚀 Equity options - share meaningfully in the company you’re helping to build.
🏦 10% employer pension contribution - because investing in future matters.
🍽️ Free office lunches - to keep you energised and focused.
👶 Enhanced parental leave - 3 months full pay paternity and 6 months full pay maternity leave, to provide extra flexibility
during the moments that matter most.
🍼 YellowNest nursery scheme - to help working parents manage childcare costs.
☀️ 25 days of Annual Leave (+ Public Holidays) - because taking time to rest matters.
🏥 Private medical insurance - 100% employee cover, giving you complete peace of mind.
💪 Wellhub Subscription - gain access to thousands of gyms, classes and wellness apps, supporting both physical and mental
wellbeing.
👀 Eye tests - because good work depends on good health.
📈 Personal development - dedicated support for learning, development, and leveling up over time.
💛 Employee Assistance Programme (EAP) - confidential wellbeing support, available whenever you need it.
🚲 Bike2Work scheme and 🚆 Season ticket loan - to make getting to work easier and greener.
🚗 Octopus EV salary sacrifice - for a simpler, more sustainable way to drive electric.
🔎 Watch this space, we’re continuing to build this as we grow…
We value diversity and are committed to equal employment opportunity regardless of sex, race, religion, ethnicity, nationality,
disability, age, sexual orientation or gender identity. We strongly encourage individuals from groups traditionally
underrepresented in tech to apply. To help make a change, we sponsor bright women from disadvantaged backgrounds through their
university degrees in science and mathematics.
We collect diversity and inclusion data solely for the purpose of monitoring the effectiveness of our equal opportunities policies
and ensuring compliance with UK employment and equality legislation. This information is confidential, used only in aggregate
form, and will not influence the outcome of your application.
ABOUT US PhysicsX is a deep-tech company with roots in numerical physics and Formula One, dedicated to accelerating hardware innovation at the speed of software. We are building an AI-driven simulation software stack for engineering and manufacturing across advanced industries. By enabling high-fidelity, multi-physics simulation through AI inference across the entire engineering lifecycle, PhysicsX unlocks new levels of optimization and automation in design, manufacturing, and operations — empowering engineers to push the boundaries of possibility. Our customers include leading innovators in Aerospace & Defense, Materials, Energy, Semiconductors, and Automotive. NOTE: WE ARE CURRENTLY RECRUITING FOR MULTIPLE LEVELS AND POSITIONS, HOWEVER PLEASE ONLY APPLY FOR THE ROLE THAT BEST ALIGNS WITH YOUR SKILLSET AND CAREER GOALS. WHAT YOU WILL DO * Own Research work-streams at a high-level to deliver outcomes. * Align priorities with problem stakeholders, internal and external. * Set the technical direction for the stream and apply judgement and taste to drive progress. * Plan roadmaps with clear milestones for key decisions and outcomes. * Organise and guide the more junior members of the team to effectively execute and deliver against this roadmap. * Communicate purpose and key outcomes to raise awareness across the company and create opportunities for use and deployment. * Contribute towards Research group strategy and culture. * Identify research areas that would be valuable to the company and champion their development, ordering wrt other research objectives. * Promote effective working patterns and proactively flag issues with team dynamics to foster a productive environment. * Nurture younger colleagues to grow their skillset and guide their professional development. * The below activities in particular. * Work closely with our machine learning engineers, simulation engineers, and customers to translate physics and engineering challenges into mathematical problem formulations. * Build models to predict the behaviour of physical systems using state-of-the-art machine learning and deep learning techniques. * Discuss the results and implications of your work with colleagues and customers, especially how these results can address real-world problems. * Collaborate with colleagues beyond the research team to translate your models into production-ready code. * Communicate your work to others internally and externally as called for in paper publication venues, industry workshops, customer conversations, etc. This will involve writing for academic and non-academic audiences. WHAT YOU BRING TO THE TABLE * Ability to scope and effectively deliver projects. * Enthusiasm about using machine learning, especially deep learning and/or probabilistic methods, for science and engineering. * Strong problem-solving skills and the ability to analyse issues, identify causes, and recommend solutions quickly. * Excellent collaboration and communication skills — with teams and customers alike. * PhD in computer science, machine learning, applied statistics, mathematics, physics, engineering, or a related field, with particular expertise in any of the following: 1. operator learning (neural operators), or other probabilistic methods for PDEs; 2. geometric deep learning or other 3D computer vision methods for point-cloud or mesh-structured data; 3. generative models for geometry and spatiotemporal data (VAEs, Diffusion Models, Bayesian non-parametric, scaling to large datasets, etc.). * Ideally, >4 years of experience in a data-driven role in a professional industry setting, where you have been instrumental in: * building machine learning models and pipelines in Python, using common libraries and frameworks (PyTorch / CUDA, ideally with exposure to JAX, NumPy / SciPy), especially including deep learning applications; * developing models for bespoke problem settings that involve high-dimensional data (spatiotemporal, geometric, physical); * iterating on network architectures and model structure, tuning and optimising for inductive biases, improved generalisability, and improved performance; * combining theoretical reasoning with empirical intuition to guide investigation; * formulating and running experiment pipelines to benchmark models and produce comparable results; * writing skills for communication complex technical concepts to peers and non-peers, tailoring the message for the required audience. * Publication record in reputable venues that demonstrates mastery in your field, and in particular the domains of interest listed above. Desirable venues include (but not limited to): NeurIPS, ICML, ICLR, UAI, AISTATS, AAAI, Siggraph, CVPR or TPAMI/JMLR. WHAT WE OFFER Build what actually matters Help shape an AI-native engineering company at a formative stage, tackling problems that genuinely matter for industry and society. This is work with real-world impact - and something you can be proud to stand behind. Learn alongside exceptional people Work with a high-caliber, collaborative team of engineers, scientists, and operators who care deeply about doing great work, and about helping each other get better. We come from diverse backgrounds, but we share a commitment to operating at the highest level and addressing some of the most complex challenges out there. If you’re ambitious, thoughtful, and driven by impact, you’ll feel at home. Influence over hierarchy We operate with a flat structure: good ideas win - wherever they come from. Questioning assumptions and challenging the status quo isn’t just welcomed, it’s expected. Sustainable pace, long-term ambition Building meaningful technology is a marathon, not a sprint. We believe in balancing focused, ambitious work with a life beyond it. Our hybrid model blends time together in our Shoreditch office with work-from-home days, giving you the flexibility to work sustainably while staying connected in person. And it doesn’t stop there … 🚀 Equity options - share meaningfully in the company you’re helping to build. 🏦 10% employer pension contribution - because investing in future matters. 🍽️ Free office lunches - to keep you energised and focused. 👶 Enhanced parental leave - 3 months full pay paternity and 6 months full pay maternity leave, to provide extra flexibility during the moments that matter most. 🍼 YellowNest nursery scheme - to help working parents manage childcare costs. ☀️ 25 days of Annual Leave (+ Public Holidays) - because taking time to rest matters. 🏥 Private medical insurance - 100% employee cover, giving you complete peace of mind. 💪 Wellhub Subscription - gain access to thousands of gyms, classes and wellness apps, supporting both physical and mental wellbeing. 👀 Eye tests - because good work depends on good health. 📈 Personal development - dedicated support for learning, development, and leveling up over time. 💛 Employee Assistance Programme (EAP) - confidential wellbeing support, available whenever you need it. 🚲 Bike2Work scheme and 🚆 Season ticket loan - to make getting to work easier and greener. 🚗 Octopus EV salary sacrifice - for a simpler, more sustainable way to drive electric. 🔎 Watch this space, we’re continuing to build this as we grow… We value diversity and are committed to equal employment opportunity regardless of sex, race, religion, ethnicity, nationality, disability, age, sexual orientation or gender identity. We strongly encourage individuals from groups traditionally underrepresented in tech to apply. To help make a change, we sponsor bright women from disadvantaged backgrounds through their university degrees in science and mathematics. We collect diversity and inclusion data solely for the purpose of monitoring the effectiveness of our equal opportunities policies and ensuring compliance with UK employment and equality legislation. This information is confidential, used only in aggregate form, and will not influence the outcome of your application.
📈 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. It's the transaction infrastructure that replaces what a traditional trading desk does — forecasting energy prices and volume, building a real-time picture of the portfolio, optimising the fees placed on every quote, and autonomously managing hedging decisions. All of it running continuously. All of it on the critical path for every deal tem closes. Machine learning is at the heart of it. Rosso combines 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. We've proved the concept. tem now serves 2% of the UK market. The next step is building a pricing engine that doesn't just react — one that proactively drives growth by targeting the right customers at the right time, at the right price, while protecting margin and portfolio balance. Then taking that internationally. We're looking for a Senior Staff Machine Learning Engineer to own pricing ML within Rosso. This is a hands-on senior IC role with real technical authority — you set the strategy, define the mathematical approach, build the models, and ship them. You work closely with MLOps and software engineers, but you don't wait on them. The hard part of this job is the formulation, not the infrastructure. 🚀 Responsibilities * Own the technical direction for pricing ML. Define what to build and how. Set the roadmap for the pricing engine as a core piece of tem's IP — and be accountable for its performance. * Formulate and solve the pricing problem properly. The mathematical foundation doesn't fully exist yet. Your first job is to define it: a dynamic, real-time system that simultaneously optimises for signing probability, portfolio balance, and margin. Choose the right approach — stochastic programming, reinforcement learning, classical ML, or a hybrid — based on the problem, not familiarity. * Build and ship models end-to-end. Own the modelling and data layer. Write production-grade Python. Architect models with deployment in mind and carry them through to production — you can execute without being blocked by engineering dependencies. * Solve imbalance problems. Develop probabilistic models to optimise risk management and short-term balancing decisions in a highly dynamic environment. * Be the voice of pricing ML across the business. Commercial, product, and engineering teams depend on this engine. They need to understand what it's doing and why. You make that happen — clearly, without losing precision. 🎯 Requirements Must-haves: * Deep experience building ML systems for pricing, revenue optimisation, or real-time decision-making — at companies where pricing is the product, not a supporting function. Track record of models that reached production and moved commercial metrics. * Strong foundation in stochastic optimisation and probabilistic modelling. The judgement to formulate ambiguous business problems mathematically before reaching for a tool. * First-principles reasoning across methods. You choose between stochastic programming, reinforcement learning, classical ML, or a simple heuristic based on what the problem demands. * The engineering depth to match your modelling. Production-grade Python, high bar for code quality, and the ability to carry models from formulation to deployment without being blocked. * Senior technical leadership. A track record of setting direction for a significant technical area, influencing cross-functional teams, and translating complex model behaviour into clear terms for commercial, product, and engineering stakeholders — so decisions are understood and acted on. Bonus points: * Experience with real-time pricing at scale — ride-hailing, food delivery, logistics, or similar environments where latency and portfolio effects matter. * Familiarity with energy markets, power trading, or portfolio risk management. * PhD or equivalent research depth in a quantitative discipline — statistics, applied mathematics, operations research, or similar. * Ability to reason about trade-offs between optimisation solvers (Gurobi etc.) and gradient-based methods (PyTorch etc.), and the judgement to know when to reach for each. * Experience with causal inference or reinforcement learning in applied commercial settings. 🗣️ Interview Process Our processes normally take around 2–3 weeks from first call to offer — please let us know about any timeline adjustments you need. 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.
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.