Backend Engineer - Recommendation (all genders)

Location: Hamburg or Berlin, de

Company Description

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.

Job Description

• Develop the recommendation engine powering ABOUT YOU's homepage, product, and outfit pages in Node.js/TypeScript
• Serve offline-trained ML models (matrix factorization, brand similarity, image embeddings) at Black-Friday scale from Valkey, DynamoDB, and OpenSearch
• Design personalization logic: feed assembly, fallback chains, deduplication, diversity, and A/B experimentation
• Build GenAI product features like our streaming Gemini fashion advisor, focusing on low latency, session state, and token cost control
• Own reverse-ETL pipelines that move BigQuery model outputs into high-performance hot stores
• Instrument recommendation coverage, track business metrics via SQS/BI systems, and shape architecture alongside our Tech Lead

Qualifications

• You take end-to-end responsibility for our recommendation engine and love seeing your changes directly impact customer engagement
• 3+ years of experience building high-throughput backend services (Node.js/TypeScript preferred, or fast-converting from Java, Go, or Kotlin)
• Real depth in Redis/Valkey data modeling, caching hierarchies (multi-tier, TTLs/invalidation), and binary payloads (Protobuf/Avro)
• High-throughput mindset: comfortable operating APIs that scale to 10k+ rps under strict latency SLOs
• You're excited to bridge backend engineering and ML by serving model scores, embeddings, or LLM features in live systems
• Clear communication skills in English and a data-driven, experiment-friendly mindset

Nice to Have

• RecSys fundamentals (collaborative filtering, matrix factorization, cold-start handling, diversity algorithms)
• Streaming GenAI / LLM product experience (chat UX, prompt caching, guardrails)
• Experience with AWS serverless (DynamoDB modeling, SQS/SNS) and OpenSearch k-NN indices
• Performance profiling (clinic.js, flamegraphs) and load testing (k6)

Additional Information

Your perks at a glance: Visit our benefits page.

Simply apply online via our career page - we will get back to you as soon as possible!

A Place Where You Can Be You
We take it as our responsibility to create an environment where everyone feels welcome, exactly as they are.
Different backgrounds and perspectives make us stronger and shape our culture in ways that matter.
What we stand for internally, we stand for as a brand: acceptance, inclusion, and a fairer approach to fashion.