Senior Backend Engineer - Ranking Systems (all genders)

ABOUT YOU is one of Europe’s fastest growing e-commerce companies. Based in Hamburg and Berlin, we operate at the intersection of fashion and technology. Our mission is to rethink online shopping and make it personal and seamless. This takes more than good ideas. It takes people who take initiative and challenge the status quo. We believe in flat hierarchies, direct communication, and pragmatic decisions. No long approval chains. Just ownership, trust, and clear responsibility. We work hard, but we also believe in enjoying the ride together - over team lunches, afterwork drinks, company events, or a quick coffee in between meetings. If this sounds like you, ABOUT YOU could be the right place to bring in your perspective.

Responsibilities

Shape how millions of users see products by blending ML model outputs with business logic (like campaign boosts or sponsored items); Build and own our high-throughput ranking engine ("Spotsetter") to ensure fast, deterministic, and fair product sorting; Design reliable batch write pipelines that stream data from BigQuery straight into high-performance relational stores like Postgres and MySQL; Develop low-latency serving APIs with Fastify and Node.js/TypeScript; Work closely with data engineers, product managers, and commercial teams to make data-driven ranking decisions; Architectural freedom: collaborate with our Tech Lead, bring in your own ideas, and keep our codebase clean

Requirements

You love digging into ranking problems, taking deep ownership of a product, and seeing your changes move real business metrics; 5+ years of experience with backend systems (Node.js/TypeScript preferred, but we welcome fast learners from Java, Go, or Kotlin); Strong hands-on SQL knowledge (Postgres/MySQL schema design, query optimization, and batch operations beyond basic ORMs); Good algorithmic intuition for sorted data, deduplication, latency trade-offs, and constraint logic; You're excited to bridge backend engineering and ML by serving model scores or ranking data in live systems; Clear communication skills in English and a pragmatic, solution-oriented mindset

Nice to have

Experience with job queues (BullMQ, Redis) or batch processing pipelines; Exposure to cloud tooling (AWS Step Functions, CDK, GCP/BigQuery); Background in e-commerce, sponsored products, or ad-tech systems; Curiosity about learning-to-rank algorithms