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Senior Staff Machine Learning Engineer, ML Understanding

Reddit· ML & Search
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Remote$266k - $372.4kFull-timePosted 2w ago

About the role

Senior Staff ML Engineer to lead Reddit’s user understanding initiative, building a unified, high-fidelity representation of users for personalization across feeds, search, notifications, and ads, with a focus on leveraging GenAI and large-scale embeddings.

Responsibilities

  • Design User Understanding Strategy: Define a unified user understanding framework and strategy: how users are represented (embeddings, tags, attributes, LLM-based user profile), how they are computed, stored, and exposed.
  • Build Foundational User Models: Lead design and implementation of advanced user models, e.g. large-scale user representation learning (sequence-based, multi-interest, multi-task) that share representations across surfaces to improve personalization across Feeds, Notification, Search and Ads, balancing latency, cost, and performance.
  • Reimagine user understanding with LLM/Gen-AI: Evolve user modeling using LLMs to build richer user understanding (dynamic profiles, intent inference, semantic reasoning over behavior).
  • Ship Large Scale User Understanding as a System: Partner with platform teams to design and build core components for large-scale learning and serving (embeddings storage/retrieval, feature pipelines, APIs); ensure low-latency serving and MLOps integration.
  • Drive Cross-Team Integration & Impact: Partner with Feeds, Notification, Search and Ads teams to drive experimentation and measurable end-to-end impact on key metrics.
  • Set Technical Bar & Mentor: Mentor engineers, lead design reviews, drive best practices across the user understanding domain.

Qualifications

  • At least 10 years experience building and scaling production-grade ML systems, particularly in user modeling, large-scale representation learning, or recommender systems.
  • Track record of driving ambiguous, high-impact initiatives from concept to production.
  • Product- and impact-oriented mindset focusing on metrics (engagement, retention, revenue) in addition to model quality.
  • Strong fundamentals in mainstream user understanding ML approaches (representation learning, behavioral modeling, user clustering) and trade-offs in real-world systems.
  • Experience or strong intuition applying LLMs/foundation models to evolve existing systems in the GenAI era.
  • Systems thinking across data, training, evaluation, serving, and adoption for end-to-end impact.
  • Ability to influence beyond own team and drive alignment with product, infra, and other ML teams.
  • Interest in raising technical bar via mentoring, design reviews, and engineering best practices.
  • Comfort navigating trade-offs across quality, latency, cost, and safety in large-scale, user-facing systems.

Skills

Required:User representation learningLLM / GenAI for user modelingSystem design for ML platforms

Benefits

  • Comprehensive Healthcare Benefits and Income Replacement Programs
  • 401k with Employer Match
  • Global Benefit programs covering workspace, professional development, and caregiving support
  • Family Planning Support
  • Gender-Affirming Care
  • Mental Health & Coaching Benefits
  • Flexible Vacation & Paid Volunteer Time Off
  • Generous Paid Parental Leave
Last updated Oct 7, 2026. Interested? Apply on the company site.
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