Senior Staff Machine Learning Engineer, ML Understanding

About the Role

Day-to-day, this role involves close collaboration with product, infrastructure, and downstream ML teams to drive measurable impact. It requires a deep understanding of mainstream ML user modeling approaches, including large-scale embeddings, user interest modeling, and the ability to reimagine these systems in the context of the GenAI era. Leveraging Large Language Models (LLMs) and foundation models will be crucial for unlocking step-change improvements in fidelity, adaptability, and expressiveness.

Reddit, as a community of communities, is built on shared interests, passion, and trust. It's home to the most open and authentic conversations on the internet, with over 100,000 active communities and approximately 121 million daily active unique visitors. The impact of this role will be felt across the platform, shaping how users experience Reddit every day, from the content they see to the communities they connect with.

What You Will Do

• Design and lead the implementation of Reddit's core user representation layer, spanning embeddings, interest modeling, and key user attributes.
• Develop a unified user understanding framework and strategy, defining how users are represented, computed, stored, and exposed.
• Provide thought leadership in user understanding and user modeling, advancing the state-of-the-art in the field.
• Lead the design and implementation of advanced user models, such as large-scale user representation learning.
• Reimagine user understanding with LLM/Gen-AI, building richer user understanding through dynamic user profiles, intent inference, and semantic reasoning over user behavior.
• Partner with platform teams to design and build core components for large-scale learning and serving.
• Collaborate with ML/Ranking infra to ensure low-latency serving, high availability, and integration with MLOps systems.
• Ensure the foundation is scalable, reliable, and widely adopted across Feeds, Search, Notifications, and Ads.
• Drive measurable impact through close collaboration with product, infrastructure, and downstream ML teams.

What We Are Looking For

• Deep expertise in mainstream ML user modeling approaches, including large-scale embeddings and user interest modeling.
• Ability to reimagine these systems in the GenAI era, leveraging LLMs and foundation models.
• Experience in designing and implementing complex machine learning systems that have been successfully deployed.
• Strong technical leadership and collaboration skills, with the ability to partner closely with various teams.
• A bachelor's or master's degree in Computer Science, Machine Learning, or a related field.
• Experience with machine learning frameworks and tools.
• Strong understanding of software development principles and practices.
• Excellent problem-solving skills, with the ability to approach complex problems systematically.

Nice to Have

• Experience with Large Language Models (LLMs) and their applications in user modeling.
• Knowledge of foundation models and their potential in enhancing user understanding.
• Familiarity with cloud computing platforms and containerization (e.g., Docker).
• Experience with agile development methodologies and version control systems (e.g., Git).
• Certification in machine learning or a related field.

Benefits and Perks

• Competitive salary and equity package.
• Opportunity to work on a high-impact project that directly influences the user experience for hundreds of millions of people.
• Remote work flexibility, with the option to work from anywhere in the United States.
• Comprehensive health insurance, including medical, dental, and vision coverage.
• Generous paid time off (PTO) policy, allowing for a healthy work-life balance.
• Access to professional development opportunities, including training, conferences, and workshops.
• Collaborative and dynamic work environment with a team of skilled professionals.

• Highlight your ML expertise: Showcase your experience with mainstream ML user modeling approaches and your ability to leverage LLMs for enhanced user understanding.
• Prepare to discuss system design: Be ready to dive deep into how you would design and implement complex machine learning systems, focusing on scalability and reliability.
• Showcase your technical leadership: Provide examples of your technical leadership and collaboration skills, especially in driving the adoption of ML systems across various teams.
• Demonstrate problem-solving skills: Approach complex problems systematically, and be prepared to discuss how you would tackle challenges in user modeling and personalization.
• Familiarize yourself with Reddit's platform: Understand Reddit's community-driven approach and how user understanding initiatives can impact the user experience across the platform.
• Be ready to discuss innovation: Come prepared to talk about how you stay updated with the latest advancements in ML and LLMs, and how you see these technologies evolving user modeling in the future.
• Emphasize your passion for community: Highlight your understanding of and passion for fostering meaningful connections and communities through technology, aligning with Reddit's core values.