Member of Technical Staff (ml Engineer, Recommendations & User Modeling)

Perplexity Perplexity · AI Frontier · San Francisco, CA · AI

ML Engineer role focused on designing, building, and optimizing recommendation systems for Perplexity's consumer-facing AI products. The role involves personalization, user modeling, and integrating LLMs into ranking and retrieval pipelines to enhance user experience and drive business metrics.

What you'd actually do

  1. Own the personalization and ranking behind key product surfaces to make Perplexity more useful and drive impact on core user and business metrics.
  2. Build user modeling that captures intent, preference, and propensity, and powers more relevant, more personalized experiences.
  3. Design the decision layer that balances competing objectives to produce the best overall experience for the user.
  4. Build the data and evaluation foundations that let these systems learn and improve with usage.
  5. Help shape the technical direction of ranking, recommendations, and personalization at Perplexity.

Skills

Required

  • production recommendation systems
  • ranking systems
  • personalization systems
  • ML fundamentals
  • engagement modeling
  • model calibration
  • offline and online metrics
  • online experimentation
  • integrating LLMs into ranking
  • integrating LLMs into retrieval
  • integrating LLMs into personalization pipelines

Nice to have

  • large-scale ranking infrastructure
  • large-scale training infrastructure
  • multi-stage retrieval
  • multi-stage ranking
  • feature stores
  • real-time serving
  • user understanding
  • feed ranking
  • notifications
  • growth modeling
  • lifecycle modeling

What the JD emphasized

  • Deep, hands-on experience building production recommendation, ranking, or personalization systems at scale.
  • Experience integrating LLMs into ranking, retrieval, or personalization pipelines.
  • Taste and judgment for how personalization should work in an LLM-native product, and curiosity about reimagining it from first principles.

Other signals

  • recommendation systems
  • user modeling
  • LLM integration
  • personalization