[Remote] Senior Staff Machine Learning Engineer, ML Understanding

Note: The job is a remote job and is open to candidates in USA. Reddit is a community of communities, seeking a Senior Staff Machine Learning Engineer to lead their user understanding initiative. This role involves building a unified representation of users to enhance personalization across the platform, leveraging advanced machine learning techniques and collaborating with various teams to drive impactful results.ResponsibilitiesDesign 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. Provide thought leadership in user understanding and user modeling by setting a long-term technical vision and advancing the state-of-the-art in the fieldBuild 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 experience across key Reddit products e.g. Feeds, Notification, Search and Ads, balancing latency, cost, and performanceReimagine user understanding with LLM/Gen-AI: Evolve user modeling beyond traditional representations by leveraging LLMs to build richer user understanding (e.g., dynamic user profiles, intent inference, semantic reasoning over user behavior). Explore how LLMs can augment or unify embeddings, attributes, and taxonomies to enable more adaptive, interpretable, and context-aware personalizationShip Large Scale User Understanding as a System: Partner with platform teams to design and build core components for large-scale learning and serving: storage/retrieval for embeddings, feature pipelines, and APIs. Collaborate with ML/Ranking infra to ensure low-latency serving, high availability, and integration with MLOps systemsDrive Cross-Team Integration & Impact: Partner with Feeds, Notification, Search and Ads teams to drive experimentation and adoption of new user understanding models with product teams across Reddit, ensuring measurable end-to-end impact on key metricsSet Technical Bar & Mentor: Mentor senior to staff engineers, lead design reviews, steward technical decisions across the user understanding domain, and champion and drive engineering processes and best practicesSkillsYou have at least 10 years experience building and scaling production-grade ML systems, particularly in user modeling, large-scale representation learning, or recommender systemsYou have a track record of driving ambiguous, high-impact initiatives from concept to production, shaping both technical direction and executionYou are product- and impact-oriented: you care deeply about how your work moves real metrics (e.g., engagement, retention, revenue), not just model qualityYou bring strong fundamentals in mainstream user understanding ML approaches (e.g., representation learning, behavioral modeling, user clustering), and understand their trade-offs in real-world systemsYou are excited about the GenAI shift and have experience (or strong intuition) applying LLMs or foundation models to evolve existing systems, going beyond incremental improvementsYou think in systems, not just models: you consider data, training, evaluation, serving, and adoption as a cohesive whole, and design with end-to-end impact in mindYou influence beyond your immediate team: partnering effectively with product, infra, and other ML teams, and driving alignment across multiple stakeholdersYou raise the technical bar: mentoring senior engineers, leading design reviews, and establishing best practices for building reliable, scalable ML systemsYou are comfortable navigating trade-offs across quality, latency, cost, and safety, especially in large-scale, user-facing systemsBenefitsComprehensive Healthcare Benefits and Income Replacement Programs401k with Employer MatchGlobal Benefit programs that fit your lifestyle, from workspace to professional development to caregiving supportFamily Planning SupportGender-Affirming CareMental Health & Coaching BenefitsFlexible Vacation & Paid Volunteer Time OffGenerous Paid Parental LeaveEquity in the form of restricted stock unitsCommission (depending on the position offered)Medical, dental, and vision insurance401(k) program with employer matchGenerous time off for vacationParental leaveCompany OverviewReddit is the heart of the internet, where millions of people get together to talk about any topic imaginable. It was founded in 2005, and is headquartered in San Francisco, California, USA, with a workforce of 1001-5000 employees. Its website is https://www.redditinc.com.Company H1B SponsorshipReddit, Inc. has a track record of offering H1B sponsorships, with 22 in 2026, 99 in 2025, 63 in 2024, 76 in 2023, 70 in 2022, 68 in 2021, 39 in 2020. Please note that this does not guarantee sponsorship for this specific role.