THE ROLE & THE TEAM As a Principal Applied Scientist, you will drive the scientific vision and execution for the Bidding and Allocation engines within Zalando Marketing Services (ZMS). Every time a customer interacts with Zalando, our ad tech system must make high-stakes decisions in real-time. The system evaluates thousands of candidate ads, predicts performance metrics, and executes sophisticated auction logic to decide which ad to show and at what price. Every second, we process tens of thousands of requests where the intersection of market dynamics and machine learning creates unique challenges. In this position, you will lead our optimization efforts at the frontier of high-load low-latency Engineering, Auction Theory, and Mechanism Design. The technical scope covers Large Scale Bayesian Inference, Value based Bidding, Incrementality-based Allocation, Reinforcement Learning, and Multi-Objective Optimization. You will be instrumental in evolving our auction mechanisms to balance advertiser ROI with a premium customer experience. INCLUSIVE BY DESIGN At Zalando, our vision is to be inclusive by design. And this vision starts with our hiring - we do not discriminate on the basis of gender identity, sexual orientation, personal expression, ethnicity, religious belief, or disability status. You are welcome to leave out your picture, age, or marital status from your application. We only assess candidates on their qualifications and merit. We want to provide you with a great candidate experience. Feel free to inform us of any accommodations you may need, so we can best support you throughout the hiring process. do.BETTER - our diversity & inclusion strategy: https://corporate.zalando.com/en/our-impact/dobetter-our-diversity-and-inclusion-strategy Our employee resource groups: https://corporate.zalando.com/en/diversity-inclusion/our-employee-resource-groups WHAT WE’D LOVE YOU TO DO (AND LOVE DOING) Lead the research and development of our real-time bidding and allocation algorithms, optimizing for long-term platform health, advertiser performance, and user relevance. Advance our Auction and Mechanism Design capabilities to ensure a fair, efficient, and transparent marketplace. Collaborate with Product Managers, Engineers, and Analysts to translate complex business constraints into mathematical objective functions. Drive the long-term scientific and execution roadmap for ZMS Ad Tech and foster a culture of technical excellence. Mentor and grow senior level members of the team, acting as a force multiplier for our scientific community. WE’D LOVE TO MEET YOU IF A proven track record of research excellence, evidenced by peer-reviewed publications in relevant fields such as Computational Advertising, Auction Theory, Mechanism Design, or Game Theory (please include these in your application) and/or equivalent applied industry impact track At least 7 years of experience (commensurate with Principal level) in optimizing complex systems through automated algorithms, specifically within Ad Tech, Marketplaces, or related fields. Deep theoretical and technical expertise in optimization, control theory, or reinforcement learning applied to bidding and budget pacing. Expert knowledge of productionalizing ML models within ultra-low latency constraints and experience with large-scale distributed systems. Strong proficiency in Python and related stack, with a solid understanding of how to architect scalable data pipelines for sparse, high-dimensional advertising data. OUR OFFER Zalando provides a range of benefits, here’s an overview of what you can expect. Ask your Talent Acquisition Partner to learn more about what we offer. Employee shares program 40% off fashion and beauty products sold and shipped by Zalando, 30% off Zalando Lounge, discounts from external partners 2 paid volunteering days a year Hybrid working model, with flexible hours and up to 60% remote Work from abroad for up to 30 working days a year 27 days of vacation a year to start Relocation assistance available (subject to prior agreement) Family services, including counselling and support Health and wellbeing options (including Gympass) Mental health support and coaching available Please note that all applications must be completed using the online form - we do not accept applications via email.