Senior Backend Engineer - Search & Discovery (all genders)
About You SE & Co. KG4 days ago
Hamburg, Germany or Berlin, GermanySenior
Responsibilities
- Develop the search engine behind ABOUT YOU using Node.js/TypeScript, query understanding, entity resolution, semantic vector search, and behavioral re-ranking.
- Combine OpenSearch relevance, embedding similarity, and behavioral signals into unified search results.
- Build streaming search-index pipelines for entities, synonyms, and k-NN product vectors from BigQuery into OpenSearch.
- Integrate LLMs and embedding models with caching, fallback layers, and tight latency budgets.
- Improve search relevance through golden lists, regression suites, and continuous A/B experiments.
- Collaborate with the Tech Lead, data analysts, engineers, and product managers on architecture and technical improvements.
Requirements
- 5+ years of experience building scalable, low-latency backend APIs.
- Strong Node.js/TypeScript experience preferred, or the ability to transition quickly from Java, Go, or Kotlin.
- Deep Elasticsearch/OpenSearch experience, including mappings, custom analyzers, percolators, and scoring functions.
- Strong algorithmic intuition for ranked data, including merging, deduplication, score blending, and latency trade-offs.
- Experience serving model scores, embeddings, or LLM features in production.
- Fluent English communication skills and a pragmatic, data-curious mindset.
- Nice to have: IR/NLP fundamentals, multilingual search, relevance evaluation frameworks, vector search, k-NN/HNSW indexes, SigLIP embeddings, LLM engineering, prompt caching, Datadog LLM Observability, BigQuery, dbt, or Dagster.
Benefits
- The company provides access to a benefits program and offers a collaborative, inclusive workplace with flat hierarchies, direct communication, team lunches, afterwork drinks, company events, and informal coffee meetups.
About About You SE & Co. KG
ABOUT YOU SE & Co. KG operates an online fashion marketplace for European consumers and licenses commerce technology to brands via its SCAYLE platform. The group sells apparel and lifestyle products through its mobile app and aboutyou.com, and offers a cloud-based enterprise shop system under a license model to retailers. Founded in 2014 and headquartered in Hamburg, it is a publicly listed company.