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Zalando’s Zalando Assistant team is looking for a Principal AI Scientist to help us build the future of retail through conversational AI experiences powered by Large Language Models (LLMs) and intelligent agents. Your expertise will be key in designing and developing AI-driven systems that support fashion discovery, trend exploration, outfit recommendations, and conversational shopping experiences. As a Principal AI Scientist, you’ll play a significant role in shaping the architecture and capabilities of the Zalando Assistant. You will work on AI agents, RAG pipelines, prompt engineering, and LLM integrations, ensuring high-quality, grounded, and engaging conversations. Your domain will span the full customer lifecycle, helping drive customer activation, engagement, retention, and conversion through intelligent conversational experiences. This is a hands-on role with direct impact on customer-facing experiences. You will build and improve production AI agents used by millions of customers, working closely with product and engineering partners to deliver measurable business impact through improved product discovery, recommendation relevance, and purchase conversion. You will be at the center of fostering a culture of experimentation and innovation, ensuring assistant improvements are rigorously evaluated using both offline and online metrics. Your work will directly influence business impact, improving engagement, retention, and long-term customer value through conversational AI
Job Responsibility
Design and build conversational AI agents
Develop and integrate RAG pipelines to enrich experiences with fresh, contextual data
Design, tune, and evaluate LLM prompts to improve response quality and user engagement
Integrate LLMs with search, recommendation, and external APIs
Define and implement evaluation frameworks for conversation quality and grounding
Run experiments and optimize assistant performance for business KPIs (conversion, engagement, retention)
Own the architecture, development, and deployment of LLM-powered agent workflows
Collaborate cross-functionally with engineering, product, and data science teams
Mentor colleagues and share best practices in applied AI and agent development
Requirements
10+ years of experience in the field of engineering or applied science
Strong Python skills and experience building production-grade applications
Experience building LLM-powered applications or AI agents
Experience with prompt engineering, tuning, and evaluation
Experience with agent frameworks such as LangChain, LlamaIndex, PydanticAI, DSPy, or similar
Experience integrating LLMs with external APIs, tools, and/or RAG systems
Experience evaluating conversation quality and defining LLM metrics
Experience with vector databases, embeddings, or retrieval systems
Strong analytical and problem-solving skills
Experience optimizing AI systems for business KPIs
Nice to have
Experience evaluating conversation quality and defining LLM metrics
Experience with vector databases, embeddings, or retrieval systems
What we 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
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
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