Principal Data Scientist

Job DescriptionWe are on the lookout for Principal Data Scientists to join the AdTech data science team (Ranking Team) on our journey to always deliver amazing experiences.As part of our Vendor Team, you’ll be the driving force behind the success of thousands of restaurants, shops, and local businesses. Your contributions will empower vendors with advanced tools to manage their operations, boosting their visibility, and reach. Every feature you help build will create growth opportunities for businesses of all sizes, strengthening Delivery Hero’s ecosystem and impact.At Delivery Hero, AdTech introduces people to new food they love and enables our partners to meet their future customers at the perfect moment. We have developed a range of products to offer advertising solutions for restaurants helping them to increase their visibility and reach, improve their order conversion, and eventually drive more sales by covering the entire marketing funnel. Operating across over 50 countries around the clock, our Ad Tech connects the ideal advertiser with the ideal customer millions of times every day. Ad Tech is a fundamental area for us on our path to profitability. our data science team is at the heart of this growth, powering personalisation, Ranking, relevance, and recommendation. You will be a thought leader, driving innovation by designing and deploying our models to the forefront of technology to solve complex problems, delivering revenue for Delivery Hero at the frontline of our growth & profitability journey. In this role you willDrive transformative innovation in AI-powered ranking and bidding systems for digital advertising.Lead the creation of advanced models and strategies that redefine auction dynamics, maximise advertiser ROI, and deliver exceptional user experiences.As an expert and visionary, you will elevate our advertising intelligence capabilities, setting new industry benchmarks while shaping the future of data-driven decision-making at scale.QualificationsThe ideal candidate will demonstrate:World-Class AI and ML Authority:Expert Practitioner and thought leader in ranking models and cutting-edge approaches to personalisation, relevance, and multi-objective optimisation under uncertainty.The ability to invent and adapt novel ML architectures to solve complex problems at massive scale Actively drive the team's expertise through continuous research and implementation of state-of-the-art advancements, particularly focusing on how cutting-edge models can be integrated into our technology stack.Continuously research and evaluate state-of-the-art advancements and models in relevance and ranking to identify and implement cutting-edge solutions.Deep operational knowledge of AI frameworks (eg TensorFlow, PyTorch) and their application in designing and deploying mission-critical, ultra-low-latency real-time ranking systems.Advertising Domain Mastery & Economic Acumen:A comprehensive and deep-seated understanding of ad auctions, ad exchange platforms, and macro-economic dynamics within the programmatic advertising space.A track record of using probabilistic modelling, causal inference, and statistical rigour to validate assumptions and inform the design of new auction mechanisms and platform policies.Proven experience optimising key business metrics such as CPC, CPA, and ROAS by driving significant, measurable business outcomes across multiple product cycles.Exceptional Data and Statistical Expertise:Advanced proficiency in Python, SQL, and designing robust, end-to-end data workflows for front-end tracking, large-scale behavioral data, and feature engineering.The ability to formulate and solve the most complex multi-objective problems for ranking and bidding, effectively balancing conflicting metrics like revenue, engagement, and system stability.Strong foundation in probabilistic modelling and statistical rigour in experimental design (A/B testing, causal inference) to influence product decisions.Visionary Leadership in AI Systems:A demonstrated track record of successfully designing, building, and deploying multiple generations of large-scale AI systems that have delivered measurable, multi-million-euro business outcomes.Experience defining and driving the organizational-wide technical strategy (2+ years outlook) for Data Science and ML, influencing the roadmaps of multiple Engineering and Product teams.A history of mentoring Staff and Senior engineers/scientists and building alignment across a diverse set of engineering, product, and data organizations to deliver on ambitious, high-impact goals.Nice-to-Haves:Expertise in auction design and pricing models including dynamic and behavioral pricing.Contributions to reinforcement learning or causal inference applied to business problems.Knowledge of A/B testing methodologies and experimentation design for feature rollouts.Familiarity with large-scale recommendation systems or forecasting models for demand prediction.