Principal Applied Scientist / Lounge by Zalando (all genders)

The Role & Team

Lounge by Zalando is the leading online outlet in Europe, offering limited-time exclusive discounts on premium fashion and lifestyle brands. In this role, you'll work across the team that builds the customer-facing fashion assistant and personalized landing page. You'll work across two teams, focusing on recommendation systems and agentic development.

As the Principle Applied Scientist, you'll define the evals which measure success, and get hands-on with both custom ML models and LLM-based solutions with our engineers. This is an IC role—we expect you to have great coding skills and be able to contribute to production like a software engineer, at a fast pace.

What We'd Love You to Do

• Use LLM APIs to create the ideal fashion assistant for our customers
• Develop and improve machine learning applications, such as personalized recommendation systems, to enhance our customers' browsing experience and communication
• Translate ambiguous business challenges into research questions, contribute to defining solutions, and lead the end-to-end applied science strategy, including model selection, problem formulation, and approaches for training and inference
• Develop and implement effective evaluation frameworks to assess the impact of initiatives, analyze customer behavior, and evaluate business performance
• Use AI coding tools to deliver software at a fast pace

We'd Love to Meet You If

• Production ML expertise: At least 3 years of hands-on industry experience building and deploying scalable, high-performance recommendation or search solutions
• Software engineering: At least 5 years of experience using Python
• Deep learning & gradient boosting: Extensive hands-on experience with deep learning, gradient boosting trees, vector search etc., preferably using libraries like PyTorch, TensorFlow, CatBoost, FAISS etc.
• Large-scale data & deployment: Practical experience with large-scale data processing and deploying machine learning models to production, especially for real-time APIs (Databricks, Spark, Flink, Beam, Sagemaker, Kubernetes, REST APIs)
• Machine learning & statistics: Excellent knowledge with a strong track record in addressing real-world problems through empirical science, particularly online A/B testing
• LLM applications: LLM application development and evaluation is a highly desired bonus

Our Offer

• 27 days of holiday a year to start for full-time employees (+1 day for every calendar year up to 30 days)
• 2 paid volunteering days a year
• Hybrid working model with up to 60% remote per week, actual practice is up to each team to best support their collaboration
• Work from abroad for up to 30 working days a year
• Employee shares program
• 40% off fashion and beauty products sold and shipped by Zalando, 30% off Lounge by Zalando, discounts from external partners
• Relocation assistance available (subject to prior agreement)
• Family services, including counseling and support
• Health and wellbeing options (including Wellhub, formerly Gympass)
• Mental health support and coaching available
• Drive your development through our training platform and biannual peer-to-peer review

Inclusive by Design

If you think you have what it takes, we encourage you to apply even if you don't meet every single requirement. You may just be the right candidate for this or other roles!

At Zalando, our vision is to be the leading pan-European ecosystem for fashion and lifestyle e-commerce – one that thrives on diversity and is truly inclusive by design. We believe that diverse teams fuel innovation and creativity, and we actively seek out talent from all backgrounds. We actively seek to reduce bias in our hiring and employment processes, focusing on your qualifications, skills, and contributions.

To support this, we kindly ask that you refrain from including personal details such as your photo, age, or marital status in your CV, ensuring a fair and equitable evaluation based solely on your abilities and potential.

We are committed to providing an exceptional and accessible candidate experience for everyone. If you require any accommodations to support you throughout the hiring process, please let us know – we are here to assist you.