Senior Backend Engineer - Ranking Systems (all genders)

• 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

• 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

70000 - 85000 EUR