Senior Backend Engineer - Search & Discovery (all genders)

• Develop the search engine behind ABOUT YOU, covering query understanding, entity resolution, and semantic vector search in Node.js/TypeScript

• Blend OpenSearch relevance, embedding similarity, and behavioral re-ranking signals into unified search results

• Build search-index pipelines (entities, synonyms, k-NN product vectors) streaming data from BigQuery into OpenSearch

• Integrate LLMs and embedding models (Gemini, Vertex AI) under tight latency budgets with caching and fallback layers

• Guard search relevance using golden lists, regression suites, and continuous A/B experiments

• Shape architecture alongside our Tech Lead and collaborate closely with data analysts, engineers, and product managers

• You love investigating the "why" behind search outcomes and turning those findings into actionable technical improvements

• 5+ years of experience building scalable, low-latency backend APIs (Node.js/TypeScript preferred, or fast-converting from Java, Go, or Kotlin)

• Real depth in Elasticsearch/OpenSearch (mappings, custom analyzers, percolators, scoring functions) beyond just basic query clients

• Strong algorithmic intuition for ranked data (merging, deduplication, score blending, and latency trade-offs)

• You're excited to bridge backend engineering and ML by 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 (tokenization, multilingual search, relevance evaluation frameworks)

• Vector search experience (k-NN/HNSW indices, SigLIP embeddings, recall vs. latency tuning)

• LLM engineering (prompt caching, timeout budgets, Datadog LLM Observability)

• Familiarity with BigQuery, dbt, or Dagster pipelines

70000 - 85000 EUR