Senior Staff Software Engineer, Search & Recommendation

The role

The Senior Staff Software Engineer will own the architecture and roadmap for search and recommendations end to end. This includes query understanding, retrieval, ranking, and relevance quality for discovery surfaces.

What you will do

• Own the architecture and roadmap for search and recommendations end to end
• Define quality metrics, build offline evaluation and golden-set tooling, and run online experiments
• Design and evolve the ranking stack including engagement signal pipelines and freshness models
• Own OpenSearch in production including index design, performance, and cost
• Build candidate generation and personalization for recommendation surfaces
• Partner with Product and Trust & Safety on quality gates and cold-start behavior
• Set the engineering standard for instrumentation, flag-gated rollouts, and runbooks
• Act as the technical point of contact for discovery across backend teams and mentor engineers

Required qualifications

• 10+ years building production software
• Substantial depth in search, ranking, recommendations, or ML-driven relevance on a consumer-scale product
• Hands-on expertise with a production search engine such as OpenSearch, Elasticsearch, Lucene, or Vespa
• Experience with offline evaluation, golden sets, and A/B or interleaving frameworks
• Fluency across the recommender stack including candidate generation, feature pipelines, embedding retrieval, and re-ranking
• Strong distributed systems and backend fundamentals
• Production experience in Go or a comparable systems language
• Comfort in the data layer including SQL warehouses, streaming and batch pipelines
• Demonstrated ownership of an ambiguous area
• Clear written communication

Nice to have

• experience with AI-generated or rapidly growing content catalogs
• experience with severe cold-start conditions
• experience with ranking under trust-and-safety constraints

Benefits

• Competitive salary and generous company equity
• Medical, dental, and vision insurance – 99.99% of premiums covered by Cantina
• 42 days of paid time off, including 15 PTO days, 10 sick days, 15 company holidays, and 2 floating holidays
• Generous parental leave & fertility support
• 401(k) retirement savings plan
• Lifestyle spending account – $500/month
• Complimentary lunch and snacks for in-office employees
• One Medical membership

About the company

Cantina Labs is a social AI company developing a suite of advanced real-time models. Their flagship social AI platform is Cantina.