Lead Backend Engineer - Personalization (all genders)

We are looking for a Lead Backend Engineer (all genders) to join our Personalization area, where our Search, Recommendations and Sorting teams work together to create a personalized, relevant and inspiring shopping experience for millions of ABOUT YOU customers. The teams are part of our Customer & Shop Intelligence cluster. Depending on your background and interests, you could take a leading technical role in Search, improving how customers find products; Recommendations, shaping personalized product and outfit experiences; or Sorting, building ranking systems that balance relevance, ML and business logic. As a Lead Backend Engineer, you will take technical ownership beyond your own team, shape our architecture and engineering standards, and work closely with Engineers, Data Scientists, Analysts and Product Managers to build scalable systems with real customer and business impact.

• Take technical ownership of complex backend systems within Search, Recommendations or Sorting and drive them from concept to production
• Shape the architecture of high-throughput, low-latency services and help evolve the technical foundations of our Personalization area
• Build and operate backend systems that combine ML models, search and ranking algorithms, behavioral signals and business logic
• Drive technical decisions across team boundaries and establish standards that improve the scalability, reliability and maintainability of our systems
• Work closely with Data Scientists, Data Engineers, Analysts and Product Managers to turn data and experimentation into impactful product improvements
• Mentor and support fellow engineers, share your expertise and raise the technical bar across the teams
• Explore new technologies and approaches, bring in your own ideas and help us continuously improve how we build and operate our systems

• 7+ years of experience building scalable backend systems and APIs, with a strong track record of taking technical ownership
• Practical and recent experience with a typed programming language, ideally Node.js/TypeScript, or a strong background in Java, Go or Kotlin
• Deep understanding of backend architecture, distributed systems, APIs, data stores and performance optimization
• Strong algorithmic and analytical thinking, with an interest in search, recommendations, ranking or personalization problems
• Experience working at the intersection of backend engineering and ML, for example by serving model scores, embeddings or ML-driven features in production
• You care deeply about code quality and maintainability and actively drive technical improvements beyond your immediate area of responsibility
• You are comfortable making architectural decisions, challenging existing approaches and establishing engineering standards across team boundaries
• Strong communication skills in English and the ability to collaborate effectively with engineers, data experts and product stakeholders
• You enjoy taking ownership, sharing knowledge and enabling other engineers to grow

• A strong technical background in Search, Recommender Systems, Ranking or Personalization
• Hands-on experience with Elasticsearch/OpenSearch, Redis/Valkey, high-throughput APIs or other performance-critical backend systems
• Familiarity with ML-powered systems, LLMs, embeddings, vector search or Learning-to-Rank approaches
• Experience in operating large-scale systems with strict latency and availability requirements
• Exposure to cloud ecosystems such as AWS or GCP and data platforms including BigQuery, dbt or Dagster
• A background in e-commerce, search, recommendations, advertising or other domains where relevance and personalization directly impact the customer experience