Senior Machine Learning Engineer, Search & Recommendations

Instacart Instacart · Consumer · San Francisco, CA · Machine Learning

Instacart is seeking a Senior Machine Learning Engineer to work on their Search & Recommendations team. This role will focus on building and architecting the foundational ranking backbone models that power the entire shopping journey, optimizing for various objectives like GTV, basket lift, and retention. The engineer will also work on LLM-enhanced retrieval and features, and advance evaluation practices for online experiments and attribution pipelines. The role requires experience in ML at scale, multi-objective optimization, and production-grade ML systems.

What you'd actually do

  1. Architect the ranking backbone that unifies query understanding, personalization, multi-objective ranking, ads, and merchandising into a single adaptive platform.
  2. Design and build a search autosuggest system optimized for personalization and value-based relevance.
  3. Design long-horizon objective functions (e.g., incrementality, LTV, habit formation) and build uplift/causal value models that move beyond short-term engagement.
  4. Develop production-grade Multi-Task Learning (e.g., shared encoders, MMOE/PLE task heads) to jointly learn relevance, propensity, margin, and churn risk—ensuring calibration, constraints, and explainability.
  5. Own the inference layer: goal-aware re-rankers, diversity and quality constraints, safe exploration, and millisecond-class latency optimization.

Skills

Required

  • Python
  • SQL
  • Pandas
  • XGBoost
  • TensorFlow
  • PyTorch
  • ML at scale
  • multi-objective optimization
  • online testing
  • attribution

Nice to have

  • MMOE/PLE
  • shared encoders
  • calibration
  • counterfactual evaluation
  • uplift/causal modeling
  • contextual bandits
  • feature stores
  • caching
  • vector retrieval
  • lexical retrieval
  • re-ranking
  • A/B testing infrastructure
  • constraint-aware inference
  • LLMs as feature/recall enhancers
  • embeddings
  • adapter tuning

What the JD emphasized

  • proven track record improving ranking or recommendation systems in production
  • experience with online testing and attribution beyond CTR
  • Expertise in multi-task learning architectures
  • Experience building low-latency ranking services

Other signals

  • multi-task, multi-objective ranking
  • ranking backbone
  • customer-facing AI product