Senior Staff Engineer, Real-Time Search & Recommendations

Cantina; United States; On-site; USD 250,000 - 320,000; Full time

Benefits offered by this job

Competitive salary

Equity

Medical, dental, and vision insurance

42 days PTO

Parental leave

401(k) retirement savings plan

Lifestyle spending account

Lunch and snacks in office

One Medical membership

Job summary

Cantina is seeking a Senior Staff Software Engineer to own the search and recommendations stack end-to-end, from query understanding to ranking and surfaces in production. You will shape the roadmap for retrieval, relevance, and personalization for live traffic.

You'll work directly with Product and Trust & Safety, set engineering standards, instrument experiments, and mentor others as Cantina scales its catalog of AI characters and content. This is a hands-on leadership role.

Qualifications

• 10+ years building production software, with substantial depth in search, ranking, recommendations, or ML-driven relevance on a consumer-scale product.
• Hands-on expertise with a production search engine — OpenSearch, Elasticsearch, Lucene, Vespa, or similar — covering index and analyzer design, relevance tuning, and operating the cluster, not only querying it.
• A rigorous approach to relevance measurement: offline evaluation, golden sets, and A/B or interleaving frameworks, and you can explain what moved a metric and why.
• Fluency across the recommender stack — candidate generation, feature pipelines, embedding retrieval, re-ranking.
• Strong distributed systems and backend fundamentals, with production experience in Go or a comparable systems language, and comfort in the data layer behind it (SQL warehouses, streaming and batch pipelines).
• Demonstrated ownership of an ambiguous area: you have picked up something with no dedicated owner, decided what mattered, and can show the result.
• Clear written communication and the judgment to work with Product on real tradeoffs between relevance, freshness, safety, and latency.
• Preferred: experience with AI-generated or rapidly growing content catalogs, severe cold-start conditions, or ranking under trust-and-safety constraints.

Responsibilities

• Own architecture and roadmap for search and recommendations end to end — query understanding, retrieval, ranking, and the surfaces they feed: search, discovery, the home feed, and our trending and creator leaderboards.
• Define the quality metrics per surface, build the offline evaluation and golden-set tooling, and run the online experiments that decide whether a ranking change ships.
• Design and evolve the ranking stack — engagement signal pipelines, decay and freshness models, and the pattern we use to combine pre-computed index-time signals with live re-ranking at query time.
• Own OpenSearch in production: index and mapping design, reindex and cutover safety, query performance, cost, and the operational headroom of the clusters behind every discovery surface.
• Build candidate generation and personalization for recommendation surfaces, and partner with data and ML on the feature pipelines and models behind them.
• Work directly with Product and Trust & Safety on what “good” means for each surface — quality gates, cold-start behavior for brand-new creators and characters, and what must never be recommended.
• Set the engineering standard for the area: instrumentation, flag-gated rollouts, and runbooks that let other teams change ranking behavior without breaking it.
• Act as the technical point of contact for discovery across backend teams, and mentor the engineers whose work touches it.

Skills

Search systems

Recommender systems

Distributed systems

Go

OpenSearch/Elasticsearch

Offline evaluation

A/B testing

SQL pipelines

Tools

OpenSearch

Elasticsearch

Lucene

Vespa

SQL

Go

Job description

Cantina is seeking a Senior Staff Software Engineer to own the search and recommendations stack end-to-end, from query understanding to ranking and surfaces in production. You will shape the roadmap for retrieval, relevance, and personalization for live traffic.

You'll work directly with Product and Trust & Safety, set engineering standards, instrument experiments, and mentor others as Cantina scales its catalog of AI characters and content. This is a hands-on leadership role.